/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.exoplatform.services.jcr.impl.core.query.lucene;

import org.apache.commons.collections.IteratorUtils;
import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.collection.TransformedCollection;
import org.apache.commons.collections.iterators.TransformIterator;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.PayloadAttribute;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Fieldable;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.MultiReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermDocs;
import org.apache.lucene.search.FieldComparatorSource;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Similarity;
import org.apache.lucene.search.Sort;
import org.apache.lucene.search.SortField;
import org.exoplatform.commons.utils.ClassLoading;
import org.exoplatform.commons.utils.PrivilegedFileHelper;
import org.exoplatform.commons.utils.PrivilegedSystemHelper;
import org.exoplatform.commons.utils.SecurityHelper;
import org.exoplatform.container.configuration.ConfigurationManager;
import org.exoplatform.container.util.Utils;
import org.exoplatform.container.xml.Deserializer;
import org.exoplatform.services.document.DocumentReaderService;
import org.exoplatform.services.jcr.config.QueryHandlerEntry;
import org.exoplatform.services.jcr.config.QueryHandlerParams;
import org.exoplatform.services.jcr.config.RepositoryConfigurationException;
import org.exoplatform.services.jcr.dataflow.ItemDataConsumer;
import org.exoplatform.services.jcr.dataflow.ItemDataTraversingVisitor;
import org.exoplatform.services.jcr.datamodel.ItemData;
import org.exoplatform.services.jcr.datamodel.NodeData;
import org.exoplatform.services.jcr.datamodel.NodeDataIndexing;
import org.exoplatform.services.jcr.datamodel.PropertyData;
import org.exoplatform.services.jcr.datamodel.QPath;
import org.exoplatform.services.jcr.impl.Constants;
import org.exoplatform.services.jcr.impl.backup.ResumeException;
import org.exoplatform.services.jcr.impl.backup.SuspendException;
import org.exoplatform.services.jcr.impl.backup.Suspendable;
import org.exoplatform.services.jcr.impl.checker.InspectionReport;
import org.exoplatform.services.jcr.impl.core.LocationFactory;
import org.exoplatform.services.jcr.impl.core.SessionDataManager;
import org.exoplatform.services.jcr.impl.core.SessionImpl;
import org.exoplatform.services.jcr.impl.core.query.*;
import org.exoplatform.services.jcr.impl.core.query.lucene.directory.DirectoryManager;
import org.exoplatform.services.jcr.impl.core.query.lucene.directory.FSDirectoryManager;
import org.exoplatform.services.jcr.impl.storage.jdbc.JDBCWorkspaceDataContainer;
import org.exoplatform.services.jcr.impl.storage.jdbc.statistics.StatisticsJDBCStorageConnection;
import org.exoplatform.services.jcr.statistics.JCRStatisticsManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Element;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.security.PrivilegedAction;
import java.util.*;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;

import javax.jcr.RepositoryException;
import javax.jcr.query.InvalidQueryException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

/**
 * Implements a {@link QueryHandler} using
 * Lucene.
 */
public class SearchIndex extends AbstractQueryHandler implements IndexerIoModeListener, Suspendable
{

   private static final DefaultQueryNodeFactory DEFAULT_QUERY_NODE_FACTORY = new DefaultQueryNodeFactory();

   /** The logger instance for this class */
   private static final Logger log = LoggerFactory.getLogger("exo.jcr.component.core.SearchIndex");

   /**
    * Name of the file to persist search internal namespace mappings.
    */
   private static final String NS_MAPPING_FILE = "ns_mappings.properties";

   /**
    * The default value for property {@link #minMergeDocs}.
    */
   public static final int DEFAULT_MIN_MERGE_DOCS = 100;

   /**
    * The default value for property {@link #maxMergeDocs}.
    */
   public static final int DEFAULT_MAX_MERGE_DOCS = Integer.MAX_VALUE;

   /**
    * the default value for property {@link #mergeFactor}.
    */
   public static final int DEFAULT_MERGE_FACTOR = 10;

   /**
    * the default value for property {@link #maxFieldLength}.
    */
   public static final int DEFAULT_MAX_FIELD_LENGTH = 10000;

   /**
    * The default value for property {@link #extractorBackLog}.
    */
   public static final int DEFAULT_EXTRACTOR_BACK_LOG = Integer.MAX_VALUE;

   /**
    * The default timeout in milliseconds which is granted to the text
    * extraction process until fulltext indexing is deferred to a background
    * thread.
    */
   public static final long DEFAULT_EXTRACTOR_TIMEOUT = 100;

   /**
    * The maximum volatile index size in bytes until it is written to disk. The
    * default value is 1048576 (1MB).
    */
   public static final long DEFAULT_MAX_VOLATILE_INDEX_SIZE = 1024 * 1024;

   /**
    * volatileTime config parameter.
    * Max age of volatile. It is guaranteed that in any case volatile index will 
    * be flush to FS not later then in maxVolatileTime seconds.
    * Default is (-1) that means no maximal timeout set
    */
   public static final int DEFAULT_MAX_VOLATILE_TIME = -1;

   /**
    * The default value for {@link #termInfosIndexDivisor}.
    */
   public static final int DEFAULT_TERM_INFOS_INDEX_DIVISOR = 1;

   /**
    * The default value for {@link #reindexingPageSize}.
    */
   public static final int DEFAULT_REINDEXING_PAGE_SIZE = 100;

   /**
    * The default value for {@link #rdbmsReindexing}.
    */
   public static final boolean DEFAULT_RDBMS_REINDEXING = true;

   /**
    * The default value for {@link #asyncReindexing}.
    */
   public static final boolean DEFAULT_ASYNC_REINDEXING = false;

   /**
    * The default value for {@link #indexingThreadPoolSize}
    */
   private static final Integer DEFAULT_INDEXING_THREAD_POOL_SIZE = Runtime.getRuntime().availableProcessors();

   /**
    * The default value for {@link #indexingLoadBatchingThresholdProperty} and
    * {@link #indexingLoadBatchingThresholdNode}, knowing that -1 will disable them
    */
   private static final int DEFAULT_INDEXING_LOAD_BATCHING_THRESHOLD = -1;

   /**
    * The default value for {@link #indexingLoadBatchingThresholdTTL}
    */
   private static final long DEFAULT_INDEXING_LOAD_BATCHING_THRESHOLD_TTL = 5 * 60 * 1000L;

   /** 
    * The default value for {@link #indexRecoveryMode}. 
    */
   public static final String INDEX_RECOVERY_MODE_FROM_INDEXING = "from-indexing";

   /** 
    * The alternative value for {@link #indexRecoveryMode}. 
    */
   public static final String INDEX_RECOVERY_MODE_FROM_COORDINATOR = "from-coordinator";

   /**
    * The alternative value for {@link #indexRecoveryStrategy} rsync with force delete.
    */
   public static final String INDEX_RECOVERY_RSYNC_WITH_DELETE_STRATEGY = "rsync-with-delete";

    /**
     * The alternative value for {@link #indexRecoveryStrategy} rsync without force delete.
     */
    public static final String INDEX_RECOVERY_RSYNC_STRATEGY = "rsync";

   /**
    * The default value for {@link #indexRecoveryStrategy}.
    */
   public static final String INDEX_RECOVERY_DEFAULT_STRATEGY = "copy";

   /**
    * Default name of the error log file
    */
   private static final String ERROR_LOG = "error.log";

   /**
    * index register for current SearchIndex
    */
   private IndexRegister indexRegister;

   /**
    * The analyzer we use for indexing.
    */
   private JcrStandartAnalyzer analyzer;

   /**
    * The namespace mappings used internally.
    */
   private NamespaceMappings nsMappings;

   /**
    * The location of the search index.
    * <br>
    * Note: This is a <b>mandatory</b> parameter!
    */
   private String path;

   /**
    * minMergeDocs config parameter.
    */
   private int minMergeDocs = DEFAULT_MIN_MERGE_DOCS;

   /**
    * The maximum volatile index size in bytes until it is written to disk. The
    * default value is 1048576 (1MB).
    */
   private long maxVolatileIndexSize = DEFAULT_MAX_VOLATILE_INDEX_SIZE;

   /**
    * volatileTime config parameter.
    * Max age of volatile. It is guaranteed that in any case volatile index will 
    * be flush to FS not later then in maxVolatileTime seconds.
    */
   private int maxVolatileTime = DEFAULT_MAX_VOLATILE_TIME;

   /**
    * volatileIdleTime config parameter.
    */
   private int volatileIdleTime = 3;

   /**
    * maxMergeDocs config parameter
    */
   private int maxMergeDocs = DEFAULT_MAX_MERGE_DOCS;

   /**
    * mergeFactor config parameter
    */
   private int mergeFactor = DEFAULT_MERGE_FACTOR;

   /**
    * maxFieldLength config parameter
    */
   private int maxFieldLength = DEFAULT_MAX_FIELD_LENGTH;

   /**
    * extractorPoolSize config parameter
    */
   private int extractorPoolSize = 2 * Runtime.getRuntime().availableProcessors();

   /**
    * extractorBackLog config parameter
    */
   private int extractorBackLog = DEFAULT_EXTRACTOR_BACK_LOG;

   /**
    * extractorTimeout config parameter
    */
   private long extractorTimeout = DEFAULT_EXTRACTOR_TIMEOUT;

   /**
    * Number of documents that are buffered before they are added to the index.
    */
   private int bufferSize = 10;

   /**
    * Compound file flag
    */
   private boolean useCompoundFile = true;

   /**
    * Flag indicating whether document order is enabled as the default
    * ordering.
    * <br>
    * Default value is: <code>false</code>.
    */
   private boolean documentOrder = true;

   /**
    * If set <code>true</code> the index is checked for consistency on startup.
    * If <code>false</code> a consistency check is only performed when there
    * are entries in the redo log on startup.
    * <br>
    * Default value is: <code>false</code>.
    */
   private boolean forceConsistencyCheck = false;

   /**
    * If set <code>true</code> the index is checked for consistency depending
    * on the {@link #forceConsistencyCheck} parameter. If set to
    * <code>false</code>, no consistency check is performed, even if the redo
    * log had been applied on startup.
    * <br>
    * Default value is: <code>false</code>.
    */
   private boolean consistencyCheckEnabled = false;

   /**
    * If set <code>true</code> errors detected by the consistency check are
    * repaired. If <code>false</code> the errors are only reported in the log.
    * <br>
    * Default value is: <code>true</code>.
    */
   private boolean autoRepair = true;

   /**
    * The uuid resolver cache size.
    * <br>
    * Default value is: <code>1000</code>.
    */
   private int cacheSize = 1000;

   /**
    * The number of documents that are pre fetched when a query is executed.
    * <br>
    * Default value is: {@link Integer#MAX_VALUE}.
    */
   private int resultFetchSize = Integer.MAX_VALUE;

   /**
    * If set to <code>true</code> the fulltext field is stored and and a term
    * vector is created with offset information.
    * <br>
    * Default value is: <code>false</code>.
    */
   private boolean supportHighlighting = false;

   /**
    * The excerpt provider class. Implements {@link ExcerptProvider}.
    */
   private Class<? extends ExcerptProvider> excerptProviderClass = DefaultHTMLExcerpt.class;

   /**
    * The path to the indexing configuration file.
    */
   private String indexingConfigPath;

   /**
    * The DOM with the indexing configuration or <code>null</code> if there is
    * no such configuration.
    */
   private Element indexingConfiguration;

   /**
    * The indexing configuration.
    */
   private IndexingConfiguration indexingConfig;

   /**
    * The name and path resolver used internally.
    */
   private LocationFactory npResolver;

   /**
    * The indexing configuration class. Implements
    * {@link IndexingConfiguration}.
    */
   private Class<? extends IndexingConfiguration> indexingConfigurationClass = IndexingConfigurationImpl.class;

   /**
    * The class that implements {@link SynonymProvider}.
    */
   private Class<? extends SynonymProvider> synonymProviderClass;

   /**
    * The currently set synonym provider.
    */
   private SynonymProvider synProvider;

   /**
    * The configuration path for the synonym provider.
    */
   private String synonymProviderConfigPath;

   /**
    * The FileSystem for the synonym if the query handler context does not
    * provide one.
    */
   private InputStream synonymProviderConfigFs;

   /**
    * Indicates the index format version which is relevant to a <b>query</b>.
    * This value may be different from what
    * {@link MultiIndex#getIndexFormatVersion()} returns because queries may be
    * executed on two physical indexes with different formats. Index format
    * versions are considered backward compatible. That is, the lower version
    * of the two physical indexes is used for querying.
    */
   private IndexFormatVersion indexFormatVersion;

   /**
    * The class that implements {@link SpellChecker}.
    */
   private Class<? extends SpellChecker> spellCheckerClass;

   /**
    * The spell checker for this query handler or <code>null</code> if none is
    * configured.
    */
   private SpellChecker spellChecker;

   /**
    * Return most popular results.
    */
   private boolean spellCheckerMorePopular = true;

   /**
    * Minimal distance between spell checked word and proposed word. 
    */
   private float spellCheckerMinDistance = 0.55f;

   /**
    * The similarity in use for indexing and searching.
    */
   private Similarity similarity = Similarity.getDefault();

   /**
    * The name of the directory manager class implementation.
    */
   private String directoryManagerClass = FSDirectoryManager.class.getName();

   /**
    * The directory manager.
    */
   private DirectoryManager directoryManager;

   /**
    * The termInfosIndexDivisor.
    */
   private int termInfosIndexDivisor = DEFAULT_TERM_INFOS_INDEX_DIVISOR;

   /**
    * The sort comparator source for indexed properties.
    */
   private FieldComparatorSource scs;

   /**
    * The insensitive sort comparator source for indexed properties.
    */
   private FieldComparatorSource sics;

   /**
    * Flag that indicates whether the hierarchy cache should be initialized
    * immediately on startup.
    */
   private boolean initializeHierarchyCache = true;

   /**
    * Indicates if this <code>SearchIndex</code> is closed and cannot be used
    * anymore.
    */
   private final AtomicBoolean closed = new AtomicBoolean(false);

   /**
    * Allows or denies queries while index is offline.
    */
   private final AtomicBoolean allowQuery = new AtomicBoolean(true);

   /**
    * Text extractor for extracting text content of binary properties.
    */
   private DocumentReaderService extractor;

   public static final int DEFAULT_ERRORLOG_FILE_SIZE = 50; // Kb

   private int errorLogfileSize = DEFAULT_ERRORLOG_FILE_SIZE;

   /**
    * The ErrorLog of this <code>MultiIndex</code>. All changes that must be in
    * index but interrupted by IOException are here.
    */
   private ErrorLog errorLog;

   /**
    * The unique id of the workspace corresponding to current instance of {@link SearchIndex}
    */
   private final String wsId;

   private final ConfigurationManager cfm;

   /**
    * Maximum amount of nodes which can be retrieved from storage for re-indexing purpose. 
    */
   private int reindexingPageSize = DEFAULT_REINDEXING_PAGE_SIZE;

   /**
    * Indicates what reindexing mechanism need to use. 
    */
   private boolean rdbmsReindexing = DEFAULT_RDBMS_REINDEXING;

   /** 
    * The way to create initial index.. 
    */
   private String indexRecoveryMode = INDEX_RECOVERY_MODE_FROM_COORDINATOR;

   private RSyncConfiguration rsyncConfiguration;

   /**
    * The way to create initial index..
    */
   private String indexRecoveryStrategy = INDEX_RECOVERY_DEFAULT_STRATEGY;

   /**
    * Defines reindexing synchronization policy. Whether or not start it asynchronously  
    */
   private boolean asyncReindexing = DEFAULT_ASYNC_REINDEXING;

   /**
    * Waiting query execution until resume. 
    */
   protected final AtomicReference<CountDownLatch> latcher = new AtomicReference<CountDownLatch>();

   /**
    * Indicates if component suspended or not.
    */
   protected final AtomicBoolean isSuspended = new AtomicBoolean(false);

   /**
    * The amount of current working threads.
    */
   protected AtomicInteger workingThreads = new AtomicInteger();

   protected final Set<String> recoveryFilterClasses;

   protected List<AbstractRecoveryFilter> recoveryFilters = null;

   protected Map<String, String> optionalParameters = new HashMap<String, String>();

   protected Integer indexingThreadPoolSize = DEFAULT_INDEXING_THREAD_POOL_SIZE;

   private boolean indexingLoadBatchingThresholdDynamic;

   private long indexingLoadBatchingThresholdTTL;

   private int indexingLoadBatchingThresholdProperty = DEFAULT_INDEXING_LOAD_BATCHING_THRESHOLD;

   private int indexingLoadBatchingThresholdNode = DEFAULT_INDEXING_LOAD_BATCHING_THRESHOLD;

   private boolean indexingLoadPropertyByName;

   /**
    * This timer is used to update the load batching thresholds when they are enabled and the dynamic mode is enabled too
    */
   private static volatile Timer TIMER;

   /**
    * Task that is periodically called by the timer to update the load batching thresholds according to the statistics
    */
   private TimerTask updateLoadBatchingThresholdTask;

   /**
    * Working constructor.
    * 
    * @throws RepositoryConfigurationException
    * @throws IOException
    */
   public SearchIndex(String wsId, QueryHandlerEntry queryHandlerConfig, ConfigurationManager cfm) throws IOException,
      RepositoryConfigurationException
   {
      this.wsId = wsId;
      this.analyzer = new JcrStandartAnalyzer();
      this.cfm = cfm;
      this.recoveryFilterClasses = new LinkedHashSet<String>();
      SearchIndexConfigurationHelper searchIndexConfigurationHelper = new SearchIndexConfigurationHelper(this);
      searchIndexConfigurationHelper.init(queryHandlerConfig);
   }

   /**
    * Working constructor.
    * 
    * @throws RepositoryConfigurationException
    * @throws IOException
    */
   public SearchIndex(QueryHandlerEntry queryHandlerConfig, ConfigurationManager cfm) throws IOException,
      RepositoryConfigurationException
   {
      this(null, queryHandlerConfig, cfm);
   }

   /**
    * For test constructor.
    */
   public SearchIndex()
   {
      this.analyzer = new JcrStandartAnalyzer();
      this.cfm = null;
      this.wsId = null;
      this.recoveryFilterClasses = new LinkedHashSet<String>();
   }

   /**
    * Initializes this <code>QueryHandler</code>. This implementation requires
    * that a path parameter is set in the configuration. If this condition is
    * not met, a <code>IOException</code> is thrown.
    * 
    * @throws IOException
    *             if an error occurs while initializing this handler.
    * @throws RepositoryException
    */
   @Override
   public void doInit() throws IOException, RepositoryException
   {
      QueryHandlerContext context = getContext();
      setPath(context.getIndexDirectory());
      if (path == null)
      {
         throw new IOException("SearchIndex requires 'path' parameter in configuration!");
      }

      final File indexDirectory;
      if (path != null)
      {
         indexDirectory = new File(path);

         if (!indexDirectory.exists())
         {
            if (!indexDirectory.mkdirs())
            {
               throw new RepositoryException("fail to create index dir " + path);
            }
         }
      }
      else
      {
         throw new IOException("SearchIndex requires 'path' parameter in configuration!");
      }
      log.info("Index created: " + path);

      extractor = context.getExtractor();
      synProvider = createSynonymProvider();
      directoryManager = createDirectoryManager();

      if (context.getParentHandler() instanceof SearchIndex)
      {
         // use system namespace mappings
         SearchIndex sysIndex = (SearchIndex)context.getParentHandler();
         nsMappings = sysIndex.getNamespaceMappings();
      }
      else
      {
         // read local namespace mappings
         File mapFile = new File(indexDirectory, NS_MAPPING_FILE);
         if (mapFile.exists())
         {
            // be backward compatible and use ns_mappings.properties from
            // index folder
            nsMappings = new FileBasedNamespaceMappings(mapFile);
         }
         else
         {
            // otherwise use repository wide stable index prefix from
            // namespace registry
            nsMappings = new NSRegistryBasedNamespaceMappings(context.getNamespaceRegistry());
         }
      }

      scs = new SharedFieldComparatorSource(FieldNames.PROPERTIES, context.getItemStateManager(), nsMappings);
      sics =
         new SharedFieldInsensitiveComparatorSource(FieldNames.PROPERTIES, context.getItemStateManager(), nsMappings);
      
      npResolver = new LocationFactory(nsMappings);

      indexingConfig = createIndexingConfiguration(nsMappings);
      analyzer.setIndexingConfig(indexingConfig);

      MultiIndex index = new MultiIndex(this, context.getIndexingTree(), modeHandler, getIndexInfos(), getIndexUpdateMonitor());

      //register the default index
      this.indexRegister = new IndexRegister(index);

      // if RW mode, create initial index and start check
      if (modeHandler.getMode() == IndexerIoMode.READ_WRITE)
      {
         // set true if indexRecoveryFilters are required and some filter gives positive flag
         final boolean doReindexing = (index.numDocs() == 0 && context.isCreateInitialIndex());
         // if existing index should be removed
         final boolean doForceReindexing = (context.isRecoveryFilterUsed() && isIndexRecoveryRequired());

         final boolean doCheck = (consistencyCheckEnabled && (index.getRedoLogApplied() || forceConsistencyCheck));
         final ItemDataConsumer itemStateManager = context.getItemStateManager();

         if (isAsyncReindexing() && doReindexing)
         {
            log.info("Launching reindexing in asynchronous mode.");
            new Thread(new Runnable()
            {
               public void run()
               {
                  try
                  {
                     reindex(doReindexing, doForceReindexing, doCheck, itemStateManager);
                  }
                  catch (IOException e)
                  {
                     log.error(
                        "Error while reindexing the workspace. Please fix the problem, delete index and restart server.",
                        e);
                  }
               }
            }, "Reindexing-" + context.getRepositoryName() + "-" + context.getContainer().getWorkspaceName()).start();
         }
         else
         {
            reindex(doReindexing, doForceReindexing, doCheck, itemStateManager);
         }
      }
      // initialize spell checker
      spellChecker = createSpellChecker();

      log.info("Index initialized: {} Version: {}", new Object[]{path, index.getIndexFormatVersion()});
      if (!index.getIndexFormatVersion().equals(getIndexFormatVersion()))
      {
         log.warn("Using Version {} for reading. Please re-index version " + "storage for optimal performance.",
            new Integer(getIndexFormatVersion().getVersion()));
      }

      this.errorLog = doInitErrorLog(path);

      // reprocess any notfinished notifies;
      if (modeHandler.getMode() == IndexerIoMode.READ_WRITE)
      {
         recoverErrorLog(errorLog);
      }

      modeHandler.addIndexerIoModeListener(this);

      if (indexingLoadBatchingThresholdDynamic
         && (indexingLoadBatchingThresholdProperty > -1 || indexingLoadBatchingThresholdNode > -1))
      {
         // The load batching has been enabled and configured in dynamic mode
         // We first check if the statistics have been enabled
         if (JDBCWorkspaceDataContainer.STATISTICS_ENABLED)
         {
            // The statistics are enabled so we can initialize the variables
            if (indexingLoadBatchingThresholdTTL <= 0)
               indexingLoadBatchingThresholdTTL = DEFAULT_INDEXING_LOAD_BATCHING_THRESHOLD_TTL;
            log.debug("The statistics have been enabled so the load batching "
               + "thresholds will be modified dynamically");
            if (TIMER == null)
            {
               synchronized (SearchIndex.class)
               {
                  if (TIMER == null)
                  {
                     TIMER = new Timer("SearchIndex Update Load Batching Thresholds Timer", true);
                  }
               }
            }
            scheduleUpdateLoadBatchingThresholdTask();
         }
         else
         {
            log.debug("The statistics have not been enabled so the load batching "
               + "thresholds won't be modified dynamically");
         }
      }
      indexingLoadPropertyByName = indexingLoadBatchingThresholdProperty > -1;
   }

   private void scheduleUpdateLoadBatchingThresholdTask()
   {
      // define the updateLoadBatchingThresholdTask
      updateLoadBatchingThresholdTask = new TimerTask()
      {
         @Override
         public void run()
         {
            checkLoadBatchingThresholds();
         }
      };
      // schedule the task
      TIMER.schedule(updateLoadBatchingThresholdTask, 0, indexingLoadBatchingThresholdTTL);
   }

   private void unscheduleUpdateLoadBatchingThresholdTask()
   {
      if (updateLoadBatchingThresholdTask != null)
      {
         // cancel task
         updateLoadBatchingThresholdTask.cancel();
         // clear canceled tasks
         TIMER.purge();
      }
   }

   private void checkLoadBatchingThresholds()
   {
      float getByIdAvg =
         JCRStatisticsManager.getAvg(StatisticsJDBCStorageConnection.CATEGORY,
            StatisticsJDBCStorageConnection.GET_ITEM_DATA_BY_ID_DESCR);
      if (getByIdAvg <= 0f)
      {
         log.debug("Don't have any statistics about '{}' so we cannot go any further for now",
            StatisticsJDBCStorageConnection.GET_ITEM_DATA_BY_ID_DESCR);
         return;
      }
      float getByNameAvg =
         JCRStatisticsManager.getAvg(StatisticsJDBCStorageConnection.CATEGORY,
            StatisticsJDBCStorageConnection.GET_ITEM_DATA_BY_NODE_DATA_NQ_PATH_ENTRY_DESCR);
      if (getByNameAvg <= 0f)
      {
         log.debug("Don't have any statistics about '{}' so we cannot go any further for now",
            StatisticsJDBCStorageConnection.GET_ITEM_DATA_BY_NODE_DATA_NQ_PATH_ENTRY_DESCR);
         return;
      }
      log.debug("getByIdAvg = {} and getByNameAvg = {}", getByIdAvg, getByNameAvg);
      indexingLoadPropertyByName = getByIdAvg >= getByNameAvg;
      log.debug("The new value of indexingLoadPropertyByName is {}", indexingLoadPropertyByName);
      if (indexingLoadBatchingThresholdProperty > -1)
      {
         float getPropertiesByNameAvg =
            JCRStatisticsManager.getAvg(StatisticsJDBCStorageConnection.CATEGORY,
               StatisticsJDBCStorageConnection.GET_CHILD_PROPERTIES_DATA_PATTERN_DESCR);
         if (getPropertiesByNameAvg <= 0f)
         {
            log.debug("Don't have any statistics about '{}' so we cannot go any further for this threshold now",
               StatisticsJDBCStorageConnection.GET_CHILD_PROPERTIES_DATA_PATTERN_DESCR);
         }
         else
         {
            log.debug("getPropertiesByNameAvg = {}", getPropertiesByNameAvg);
            // Total amount of properties we can get individually before taking more time
            // than a unique query that will get all the properties by their name
            indexingLoadBatchingThresholdProperty =
               Math.round(getPropertiesByNameAvg / Math.min(getByIdAvg, getByNameAvg)) + 1;
            log.debug("The new value of indexingLoadBatchingThresholdProperty is {}",
               indexingLoadBatchingThresholdProperty);
         }
      }
      if (indexingLoadBatchingThresholdNode > -1)
      {
         float getAllPropertiesAvg =
            JCRStatisticsManager.getAvg(StatisticsJDBCStorageConnection.CATEGORY,
               StatisticsJDBCStorageConnection.GET_CHILD_PROPERTIES_DATA_DESCR);
         if (getAllPropertiesAvg <= 0f)
         {
            log.debug("Don't have any statistics about '{}' so we cannot go any further for this threshold now",
               StatisticsJDBCStorageConnection.GET_CHILD_PROPERTIES_DATA_DESCR);
            return;
         }
         float listAllPropertiesAvg =
            JCRStatisticsManager.getAvg(StatisticsJDBCStorageConnection.CATEGORY,
               StatisticsJDBCStorageConnection.LIST_CHILD_PROPERTIES_DATA_DESCR);
         if (listAllPropertiesAvg <= 0f)
         {
            log.debug("Don't have any statistics about '{}' so we cannot go any further for this threshold now",
               StatisticsJDBCStorageConnection.LIST_CHILD_PROPERTIES_DATA_DESCR);
            return;
         }
         log.debug("getAllPropertiesAvg = {} and listAllPropertiesAvg = {}", getAllPropertiesAvg, listAllPropertiesAvg);
         // Total amount of nodes we can load before taking more time
         // than a unique query that will get all the properties of the node
         // knowing that for one node we first by default get the list of all the properties
         // and then we get at least 4 properties of this node
         indexingLoadBatchingThresholdNode =
            Math.round(getAllPropertiesAvg / (listAllPropertiesAvg + 4 * Math.min(getByIdAvg, getByNameAvg))) + 1;
         log.debug("The new value of indexingLoadBatchingThresholdNode is {}",
            indexingLoadBatchingThresholdNode);
      }
   }

   /**
    * @return the wsId
    */
   public String getWsId()
   {
      return wsId;
   }

   /**
    * Adds new recovery filter to existing list.
    * 
    * @param recoveryFilterClassName
    */
   public void addRecoveryFilterClass(String recoveryFilterClassName)
   {
      recoveryFilterClasses.add(recoveryFilterClassName);
   }

   /**
    * Puts optional parameter not listed in {@link QueryHandlerParams}. Usually used by
    * extended plug-ins or services like RecoveryFilters.
    * 
    * @param key
    * @param value
    */
   public void addOptionalParameter(String key, String value)
   {
      optionalParameters.put(key, value);
   }

   /**
    * Returns whole set of optional (additional) parameters from QueryHandlerEntry 
    * that are not listed in {@link QueryHandlerParams}. Can be used by extended 
    * services and plug-ins requirind additional configuration. 
    * 
    * @return unmodifiable map
    */
   public Map<String, String> getOptionalParameters()
   {
      return Collections.unmodifiableMap(optionalParameters);
   }

   /**
    * Invokes all recovery filters from the set
    * @return true if any filter requires reindexing 
    */
   @SuppressWarnings("unchecked")
   private boolean isIndexRecoveryRequired() throws RepositoryException
   {
      // instantiate filters first, if not initialized
      if (recoveryFilters == null)
      {
         recoveryFilters = new ArrayList<AbstractRecoveryFilter>();
         log.info("Initializing RecoveryFilters.");
         // add default filter, if none configured.
         if (recoveryFilterClasses.isEmpty())
         {
            this.recoveryFilterClasses.add(DocNumberRecoveryFilter.class.getName());
         }
         for (String recoveryFilterClassName : recoveryFilterClasses)
         {
            AbstractRecoveryFilter filter = null;
            Class<? extends AbstractRecoveryFilter> filterClass;
            try
            {
               filterClass =
                  (Class<? extends AbstractRecoveryFilter>)ClassLoading.forName(recoveryFilterClassName, this);
               Constructor<? extends AbstractRecoveryFilter> constuctor = filterClass.getConstructor(SearchIndex.class);
               filter = constuctor.newInstance(this);
               recoveryFilters.add(filter);
            }
            catch (ClassNotFoundException e)
            {
               throw new RepositoryException(e.getMessage(), e);
            }
            catch (IllegalArgumentException e)
            {
               throw new RepositoryException(e.getMessage(), e);
            }
            catch (InstantiationException e)
            {
               throw new RepositoryException(e.getMessage(), e);
            }
            catch (IllegalAccessException e)
            {
               throw new RepositoryException(e.getMessage(), e);
            }
            catch (InvocationTargetException e)
            {
               throw new RepositoryException(e.getMessage(), e);
            }
            catch (SecurityException e)
            {
               throw new RepositoryException(e.getMessage(), e);
            }
            catch (NoSuchMethodException e)
            {
               throw new RepositoryException(e.getMessage(), e);
            }
         }
      }

      // invoke filters
      for (AbstractRecoveryFilter filter : recoveryFilters)
      {
         if (filter.accept())
         {
            return true;
         }
      }
      return false;
   }

   /**
    * @param doReindexing
    *          performs indexing if set to true 
    * @param doForceReindexing
    *          skips index existence check
    * @param doCheck
    *          checks index
    * @param itemStateManager
    * @throws IOException
    */
   private void reindex(boolean doReindexing, boolean doForceReindexing, boolean doCheck,
      ItemDataConsumer itemStateManager) throws IOException
   {
      if (doReindexing || doForceReindexing)
      {
         indexRegister.getDefaultIndex().createInitialIndex(itemStateManager, doForceReindexing);
      }
      if (doCheck)
      {
         log.info("Running consistency check...");
         try
         {
            ConsistencyCheck check = ConsistencyCheck.run(indexRegister.getDefaultIndex(), itemStateManager);
            if (autoRepair)
            {
               check.repair(true);
            }
            else
            {
               List<ConsistencyCheckError> errors = check.getErrors();
               if (errors.size() == 0)
               {
                  log.info("No errors detected.");
               }
               for (Iterator<ConsistencyCheckError> it = errors.iterator(); it.hasNext();)
               {
                  ConsistencyCheckError err = it.next();
                  log.info(err.toString());
               }
            }
         }
         catch (Exception e)
         {
            log.warn("Failed to run consistency check on index: " + e);
         }
      }
   }

   void ensureFlushed() throws IOException
   {
      if (modeHandler.getMode() == IndexerIoMode.READ_WRITE)
      {
         indexRegister.getDefaultIndex().flush();
      }
   }

   /**
    * {@inheritDoc}
    */
   public void checkIndex(ItemDataConsumer itemStateManager, boolean isSystem, final InspectionReport report)
      throws RepositoryException, IOException
   {

      // The visitor, that performs item enumeration and checks if all nodes present in 
      // persistent layer are indexed. Also collects the list of all indexed nodes
      // to optimize the process of backward check, when index is traversed to find
      // references to already deleted nodes
      class ItemDataIndexConsistencyVisitor extends ItemDataTraversingVisitor
      {
         private final IndexReader indexReader;

         private final Set<String> indexedNodes = new HashSet<String>();

         /**
          * @param dataManager
          */
         public ItemDataIndexConsistencyVisitor(ItemDataConsumer dataManager, IndexReader indexReader)
         {
            super(dataManager);
            this.indexReader = indexReader;
         }

         /**
          * {@inheritDoc}
          */
         @Override
         protected void entering(PropertyData property, int level) throws RepositoryException
         {
            // ignore properties;
         }

         /**
          * {@inheritDoc}
          */
         @Override
         protected void entering(NodeData node, int level) throws RepositoryException
         {
            // process node uuids one-by-one
            try
            {
               String uuid = node.getIdentifier();
               TermDocs docs = indexReader.termDocs(new Term(FieldNames.UUID, uuid));

               if (docs.next())
               {
                  indexedNodes.add(uuid);
                  docs.doc();
                  if (docs.next())
                  {
                     //multiple entries
                     report.logComment("Multiple entires.");
                     report.logBrokenObjectAndSetInconsistency("ID=" + uuid);
                  }
               }
               else
               {
                  report.logComment("Not indexed.");
                  report.logBrokenObjectAndSetInconsistency("ID=" + uuid);
               }
            }
            catch (IOException e)
            {
               throw new RepositoryException(e.getMessage(), e);
            }
         }

         @Override
         protected void leaving(PropertyData property, int level) throws RepositoryException
         {
            // ignore properties
         }

         @Override
         protected void leaving(NodeData node, int level) throws RepositoryException
         {
            // do nothing
         }

         @Override
         protected void visitChildProperties(NodeData node) throws RepositoryException
         {
            //do nothing
         }

         public Set<String> getIndexedNodes()
         {
            return indexedNodes;
         }
      }

      // check relation Persistent Layer -> Index
      // If current workspace is system, then need to invoke reader correspondent to system index
      ensureFlushed();
      if (isSystem)
      {
         if (getContext().getParentHandler() != null)
         {
            ((SearchIndex)getContext().getParentHandler()).ensureFlushed();
         }
      }
      IndexReader indexReader = getIndexReader(isSystem);
      try
      {
         ItemData root = itemStateManager.getItemData(Constants.ROOT_UUID);
         ItemDataIndexConsistencyVisitor visitor = new ItemDataIndexConsistencyVisitor(itemStateManager, indexReader);
         root.accept(visitor);

         Set<String> documentUUIDs = visitor.getIndexedNodes();

         // check relation Index -> Persistent Layer
         // find document that do not corresponds to real node
         // iterate on documents one-by-one
         for (int i = 0; i < indexReader.maxDoc(); i++)
         {
            if (indexReader.isDeleted(i))
            {
               continue;
            }
            final int currentIndex = i;
            Document d = indexReader.document(currentIndex, FieldSelectors.UUID);
            String uuid = d.get(FieldNames.UUID);
            if (!documentUUIDs.contains(uuid))
            {
               report.logComment("Document corresponds to removed node.");
               report.logBrokenObjectAndSetInconsistency("ID=" + uuid);
            }
         }
      }
      finally
      {
         Util.closeOrRelease(indexReader);
      }
   }

   /**
    * @return the errorLogfileSize
    */
   public int getErrorLogfileSize()
   {
      return errorLogfileSize;
   }

   /**
    * @param errorLogfileSize
    *            the errorLogfileSize to set
    */
   public void setErrorLogfileSize(int errorLogfileSize)
   {
      this.errorLogfileSize = errorLogfileSize;
   }

   /**
    * Adds the <code>node</code> to the search index.
    * 
    * @param node
    *            the node to add.
    * @throws RepositoryException
    *             if an error occurs while indexing the node.
    * @throws IOException
    *             if an error occurs while adding the node to the index.
    */
   public void addNode(NodeData node) throws RepositoryException, IOException
   {
      throw new UnsupportedOperationException("addNode");
   }

   /**
    * Removes the node with <code>uuid</code> from the search index.
    * 
    * @param id
    *            the id of the node to remove from the index.
    * @throws IOException
    *             if an error occurs while removing the node from the index.
    */
   public void deleteNode(String id) throws IOException
   {
      throw new UnsupportedOperationException("deleteNode");
   }

   /**
    * This implementation forwards the call to
    * {@link MultiIndex#update(Collection, Collection)} and transforms the two
    * iterators to the required types.
    * 
    * @param remove
    *            uuids of nodes to remove.
    * @param add
    *            NodeStates to add. Calls to <code>next()</code> on this
    *            iterator may return <code>null</code>, to indicate that a node
    *            could not be indexed successfully.
    * @throws RepositoryException
    *             if an error occurs while indexing a node.
    * @throws IOException
    *             if an error occurs while updating the index.
    */
   @Override
   public void updateNodes(final Iterator<String> remove, final Iterator<NodeData> add) throws RepositoryException,
      IOException
   {
      checkOpen();
      apply(getChanges(remove, add));
   }

   /**
    * {@inheritDoc}
    */
   public void apply(ChangesHolder changes) throws RepositoryException, IOException
   {
      checkOpen();
      // index may not be initialized, but some operation can be performed in cluster environment
      if (indexRegister.getDefaultIndex() != null)
      {
         indexRegister.getDefaultIndex().update(changes.getRemove(), changes.getAdd());
      }

      //Apply the changes on all registered index related to SearchIndex component
      for(MultiIndex index : indexRegister.getIndexList())
      {
         try
         {
            index.update(changes.getRemove(), changes.getAdd());
         }
         catch (Exception e)
         {
            log.error("Error indexing changes " + e, e);
            try
            {
               logErrorChanges(indexRegister.getErrorLogs(index), new HashSet<String>(changes.getRemove()), new HashSet<String>(changes
                       .getAddIds()));
            }
            catch (IOException ioe)
            {
               log.warn("Exception occure when errorLog writed. Error log is not complete. " + ioe, ioe);
            }
         }
      }

   }

   /**
    * {@inheritDoc}
    */
   @SuppressWarnings({"rawtypes", "unchecked"})
   public ChangesHolder getChanges(Iterator<String> remove, Iterator<NodeData> add)
   {
      final Map<String, NodeData> aggregateRoots = new HashMap<String, NodeData>();
      final Set<String> removedNodeIds = new HashSet<String>();
      final Set<String> addedNodeIds = new HashSet<String>();

      Collection<String> docIdsToRemove = IteratorUtils.toList(new TransformIterator(remove, new Transformer()
      {
         public Object transform(Object input)
         {
            String uuid = ((String)input);
            removedNodeIds.add(uuid);
            return uuid;
         }
      }));
      final AtomicInteger totalAddedDoc = new AtomicInteger();
      Collection<Document> docsToAdd = IteratorUtils.toList(new TransformIterator(add, new Transformer()
      {
         public Object transform(Object input)
         {
            NodeData state = (NodeData)input;
            if (state == null)
            {
               return null;
            }
            boolean loadAllProperties =
               indexingLoadBatchingThresholdNode > -1 && totalAddedDoc.incrementAndGet() > indexingLoadBatchingThresholdNode;
            String uuid = state.getIdentifier();
            addedNodeIds.add(uuid);
            removedNodeIds.remove(uuid);
            Document doc = null;
            try
            {
               doc = createDocument(state, getNamespaceMappings(), indexRegister.getDefaultIndex().getIndexFormatVersion(), loadAllProperties);
               retrieveAggregateRoot(state, aggregateRoots);
            }
            catch (RepositoryException e)
            {
               log.warn("Exception while creating document for node: " + state.getIdentifier() + ": " + e.toString(), e);
            }
            return doc;
         }
      }));

      // remove any aggregateRoot nodes that are new
      // and therefore already up-to-date
      aggregateRoots.keySet().removeAll(addedNodeIds);

      // based on removed UUIDs get affected aggregate root nodes
      retrieveAggregateRoot(removedNodeIds, aggregateRoots);

      // update aggregates if there are any affected
      if (aggregateRoots.size() > 0)
      {
         Collection modified = TransformedCollection.decorate(new ArrayList(), new Transformer()
         {
            public Object transform(Object input)
            {
               NodeData state = (NodeData)input;
               boolean loadAllProperties =
                  indexingLoadBatchingThresholdNode > -1
                     && totalAddedDoc.incrementAndGet() > indexingLoadBatchingThresholdNode;

               try
               {
                  return createDocument(state, getNamespaceMappings(), indexRegister.getDefaultIndex().getIndexFormatVersion(), loadAllProperties);
               }
               catch (RepositoryException e)
               {
                  log.warn("Exception while creating document for node: " + state.getIdentifier() + ": " + e.toString());
               }
               return null;
            }
         });
         modified.addAll(aggregateRoots.values());
         docIdsToRemove.addAll(aggregateRoots.keySet());
         docsToAdd.addAll(modified);
      }
      if (docIdsToRemove.isEmpty() && docsToAdd.isEmpty())
      {
         return null;
      }
      return new ChangesHolder(docIdsToRemove, docsToAdd);
   }

   /**
    * Creates a new query by specifying the query statement itself and the
    * language in which the query is stated. If the query statement is
    * syntactically invalid, given the language specified, an
    * InvalidQueryException is thrown. <code>language</code> must specify a
    * query language string from among those returned by
    * QueryManager.getSupportedQueryLanguages(); if it is not then an
    * <code>InvalidQueryException</code> is thrown.
    * 
    * @param session
    *            the session of the current user creating the query object.
    * @param itemMgr
    *            the item manager of the current user.
    * @param statement
    *            the query statement.
    * @param language
    *            the syntax of the query statement.
    * @throws InvalidQueryException
    *             if statement is invalid or language is unsupported.
    * @return A <code>Query</code> object.
    */
   public ExecutableQuery createExecutableQuery(SessionImpl session, SessionDataManager itemMgr, String statement,
      String language) throws InvalidQueryException
   {
      QueryImpl query =
         new QueryImpl(session, itemMgr, this, getContext().getPropertyTypeRegistry(), statement, language,
            getQueryNodeFactory());
      query.setRespectDocumentOrder(documentOrder);
      return query;
   }

   /**
    * This method returns the QueryNodeFactory used to parse Queries. This
    * method may be overridden to provide a customized QueryNodeFactory
    */
   protected DefaultQueryNodeFactory getQueryNodeFactory()
   {
      return DEFAULT_QUERY_NODE_FACTORY;
   }

   /**
    * Closes this <code>QueryHandler</code> and frees resources attached to
    * this handler. Also resume all waiting threads.
    */
   public void close()
   {
      closeAndKeepWaitingThreads(true);
      resumeWaitingThreads();
   }

   /**
    * Closes this <code>QueryHandler</code> and frees resources attached to
    * this handler.
    */
   private void closeAndKeepWaitingThreads(boolean completeClose)
   {
      if (!closed.get())
      {
         // cleanup resources obtained by filters
         if (completeClose && recoveryFilters != null)
         {
            for (AbstractRecoveryFilter filter : recoveryFilters)
            {
               filter.close();
            }
            recoveryFilters.clear();
            recoveryFilters = null;
         }

         if (synonymProviderConfigFs != null)
         {
            try
            {
               synonymProviderConfigFs.close();
            }
            catch (IOException e)
            {
               log.warn("Exception while closing FileSystem", e);
            }
         }
         if (spellChecker != null)
         {
            spellChecker.close();
         }
         errorLog.close();
         indexRegister.getDefaultIndex().close();
         getContext().destroy();
         closed.set(true);
         log.info("Index closed: " + path);
         modeHandler.removeIndexerIoModeListener(this);
         if (indexInfos instanceof IndexerIoModeListener)
         {
            modeHandler.removeIndexerIoModeListener((IndexerIoModeListener)indexInfos);
         }
         if (indexUpdateMonitor instanceof IndexerIoModeListener)
         {
            modeHandler.removeIndexerIoModeListener((IndexerIoModeListener)indexUpdateMonitor);
         }

         unscheduleUpdateLoadBatchingThresholdTask();
      }
   }

   /**
    * Executes the query on the search index.
    * 
    * @param session
    *            the session that executes the query.
    * @param queryImpl
    *            the query impl.
    * @param query
    *            the lucene query.
    * @param orderProps
    *            name of the properties for sort order.
    * @param orderSpecs
    *            the order specs for the sort order properties.
    *            <code>true</code> indicates ascending order,
    *            <code>false</code> indicates descending.
    * @param resultFetchHint
    *            a hint on how many results should be fetched.
    * @return the query hits.
    * @throws IOException
    *             if an error occurs while searching the index.
    * @throws RepositoryException
    */
   public MultiColumnQueryHits executeQuery(SessionImpl session, AbstractQueryImpl queryImpl, Query query,
      QPath[] orderProps, boolean[] orderSpecs, long resultFetchHint) throws IOException, RepositoryException
   {
      waitForResuming();

      checkOpen();

      workingThreads.incrementAndGet();

      try
      {
         FieldComparatorSource scs = queryImpl.isCaseInsensitiveOrder() ? this.sics : this.scs;
         Sort sort = new Sort(createSortFields(orderProps, orderSpecs, scs));
         final IndexReader reader = getIndexReader(queryImpl.needsSystemTree());
         @SuppressWarnings("resource")
         JcrIndexSearcher searcher = new JcrIndexSearcher(session, reader, getContext().getItemStateManager());
         searcher.setSimilarity(getSimilarity());
         return new FilterMultiColumnQueryHits(searcher.execute(query, sort, resultFetchHint,
            QueryImpl.DEFAULT_SELECTOR_NAME))
         {
            @Override
            public void close() throws IOException
            {
               try
               {
                  super.close();
               }
               finally
               {
                  PerQueryCache.getInstance().dispose();
                  Util.closeOrRelease(reader);
               }
            }
         };
      }
      finally
      {
         workingThreads.decrementAndGet();

         if (isSuspended.get() && workingThreads.get() == 0)
         {
            synchronized (workingThreads)
            {
               workingThreads.notifyAll();
            }
         }
      }
   }

   /**
    * Creates an excerpt provider for the given <code>query</code>.
    * 
    * @param query
    *            the query.
    * @return an excerpt provider for the given <code>query</code>.
    * @throws IOException
    *             if the provider cannot be created.
    */
   public ExcerptProvider createExcerptProvider(Query query) throws IOException
   {
      ExcerptProvider ep;
      try
      {
         ep = excerptProviderClass.newInstance();
      }
      catch (Exception e)
      {
         throw Util.createIOException(e);
      }
      ep.init(query, this);
      return ep;
   }

   /**
    * Returns the analyzer in use for indexing.
    * 
    * @return the analyzer in use for indexing.
    */
   public Analyzer getTextAnalyzer()
   {
      return analyzer;
   }

   /**
    * Returns the namespace mappings for the internal representation.
    * 
    * @return the namespace mappings for the internal representation.
    */
   public NamespaceMappings getNamespaceMappings()
   {
      return nsMappings;
   }

   /**
    * @return the indexing configuration or <code>null</code> if there is none.
    */
   public IndexingConfiguration getIndexingConfig()
   {
      return indexingConfig;
   }

   /**
    * @return the synonym provider of this search index. If none is set for
    *         this search index the synonym provider of the parent handler is
    *         returned if there is any.
    */
   public SynonymProvider getSynonymProvider()
   {
      if (synProvider != null)
      {
         return synProvider;
      }
      else
      {
         QueryHandler handler = getContext().getParentHandler();
         if (handler instanceof SearchIndex)
         {
            return ((SearchIndex)handler).getSynonymProvider();
         }
         else
         {
            return null;
         }
      }
   }

   /**
    * @return the spell checker of this search index. If none is configured
    *         this method returns <code>null</code>.
    */
   public SpellChecker getSpellChecker()
   {
      return spellChecker;
   }

   /**
    * @return the similarity, which should be used for indexing and searching.
    */
   public Similarity getSimilarity()
   {
      return similarity;
   }

   /**
    * Returns an index reader for this search index. The caller of this method
    * is responsible for closing the index reader when he is finished using it.
    * 
    * @return an index reader for this search index.
    * @throws IOException
    *             the index reader cannot be obtained.
    */
   public IndexReader getIndexReader() throws IOException
   {
      return getIndexReader(true);
   }

   /**
    * Returns the index format version that this search index is able to
    * support when a query is executed on this index.
    * 
    * @return the index format version for this search index.
    */
   public IndexFormatVersion getIndexFormatVersion()
   {
      if (indexFormatVersion == null)
      {
         if (getContext().getParentHandler() instanceof SearchIndex)
         {
            SearchIndex parent = (SearchIndex)getContext().getParentHandler();
            if (parent.getIndexFormatVersion().getVersion() < indexRegister.getDefaultIndex().getIndexFormatVersion().getVersion())
            {
               indexFormatVersion = parent.getIndexFormatVersion();
            }
            else
            {
               indexFormatVersion = indexRegister.getDefaultIndex().getIndexFormatVersion();
            }
         }
         else
         {
            indexFormatVersion = indexRegister.getDefaultIndex().getIndexFormatVersion();
         }
      }
      return indexFormatVersion;
   }

   /**
    * @return the directory manager for this search index.
    */
   public DirectoryManager getDirectoryManager()
   {
      return directoryManager;
   }

   /**
    * Returns an index reader for this search index. The caller of this method
    * is responsible for closing the index reader when he is finished using it.
    * 
    * @param includeSystemIndex
    *            if <code>true</code> the index reader will cover the complete
    *            workspace. If <code>false</code> the returned index reader
    *            will not contains any nodes under /jcr:system.
    * @return an index reader for this search index.
    * @throws IOException
    *             the index reader cannot be obtained.
    */
   protected IndexReader getIndexReader(boolean includeSystemIndex) throws IOException
   {
      // deny query execution if index in offline mode and allowQuery is false
      if (!indexRegister.getDefaultIndex().isOnline() && !allowQuery.get())
      {
         throw new IndexOfflineIOException("Index is offline");
      }
      QueryHandler parentHandler = getContext().getParentHandler();
      CachingMultiIndexReader parentReader = null;
      if (parentHandler instanceof SearchIndex && includeSystemIndex)
      {
         parentReader = ((SearchIndex)parentHandler).indexRegister.getDefaultIndex().getIndexReader();
      }

      IndexReader reader;
      if (parentReader != null)
      {
         CachingMultiIndexReader[] readers = {indexRegister.getDefaultIndex().getIndexReader(), parentReader};
         reader = new CombinedIndexReader(readers);
      }
      else
      {
         reader = indexRegister.getDefaultIndex().getIndexReader();
      }
      return new JcrIndexReader(reader);
   }

   /**
    * Creates the SortFields for the order properties.
    * 
    * @param orderProps
    *            the order properties.
    * @param orderSpecs
    *            the order specs for the properties.
    * @param scs 
    *            {@link FieldComparatorSource} case sensitive or case insensitive comparator           
    * @return an array of sort fields
    * @throws RepositoryException
    */
   protected SortField[] createSortFields(QPath[] orderProps, boolean[] orderSpecs, FieldComparatorSource scs)
      throws RepositoryException
   {
      List<SortField> sortFields = new ArrayList<SortField>();
      for (int i = 0; i < orderProps.length; i++)
      {
         if (orderProps[i].getEntries().length == 1 && Constants.JCR_SCORE.equals(orderProps[i].getName()))
         {
            // order on jcr:score does not use the natural order as
            // implemented in lucene. score ascending in lucene means that
            // higher scores are first. JCR specs that lower score values
            // are first.
            sortFields.add(new SortField(null, SortField.SCORE, orderSpecs[i]));
         }
         else
         {
            String jcrPath = npResolver.createJCRPath(orderProps[i]).getAsString(false);
            sortFields.add(new SortField(jcrPath, scs, !orderSpecs[i]));
         }
      }
      return sortFields.toArray(new SortField[sortFields.size()]);
   }

   /**
    * Creates a lucene <code>Document</code> for a node state using the
    * namespace mappings <code>nsMappings</code>.
    * 
    * @param node
    *            the node state to index.
    * @param nsMappings
    *            the namespace mappings of the search index.
    * @param indexFormatVersion
    *            the index format version that should be used to index the
    *            passed node state.
    * @param loadAllProperties
    *            Indicates whether all the properties should be loaded using the method
    *            {@link ItemDataConsumer#getChildPropertiesData(org.exoplatform.services.jcr.datamodel.NodeData)}
    * @return a lucene <code>Document</code> that contains all properties of
    *         <code>node</code>.
    * @throws RepositoryException
    *             if an error occurs while indexing the <code>node</code>.
    */
   protected Document createDocument(NodeData node, NamespaceMappings nsMappings,
                                      IndexFormatVersion indexFormatVersion, boolean loadAllProperties)
      throws RepositoryException
   {
      return createDocument(new NodeDataIndexing(node), nsMappings, indexFormatVersion, loadAllProperties, null);
   }

   /**
    * Creates a lucene <code>Document</code> for a node state using the
    * namespace mappings <code>nsMappings</code>.
    * 
    * @param node
    *            the node state to index.
    * @param nsMappings
    *            the namespace mappings of the search index.
    * @param indexFormatVersion
    *            the index format version that should be used to index the
    *            passed node state.
    * @param loadAllProperties
    *            Indicates whether all the properties should be loaded using the method
    *            {@link ItemDataConsumer#getChildPropertiesData(org.exoplatform.services.jcr.datamodel.NodeData)}
    * @return a lucene <code>Document</code> that contains all properties of
    *         <code>node</code>.
    * @throws RepositoryException
    *             if an error occurs while indexing the <code>node</code>.
    */
   protected Document createDocument(NodeDataIndexing node, NamespaceMappings nsMappings,
      IndexFormatVersion indexFormatVersion, boolean loadAllProperties, VolatileIndex volatileIndex) throws RepositoryException
   {
      NodeIndexer indexer =
         new NodeIndexer(node, getContext().getItemStateManager(), nsMappings, extractor);
      indexer.setSupportHighlighting(supportHighlighting);
      indexer.setIndexingConfiguration(indexingConfig);
      indexer.setIndexFormatVersion(indexFormatVersion);
      indexer.setLoadBatchingThreshold(indexingLoadBatchingThresholdProperty);
      indexer.setLoadPropertyByName(indexingLoadPropertyByName);
      indexer.setLoadAllProperties(loadAllProperties);
      Document doc = indexer.createDoc();
      mergeAggregatedNodeIndexes(node, doc, loadAllProperties, volatileIndex);
      return doc;
   }

   /**
    * Returns the default index.
    * 
    * @return the actual index.
    */
   public MultiIndex getIndex()
   {
      return indexRegister.getDefaultIndex();
   }

   /**
    * Change the actual default index.
    *
    */
   public void setIndex(MultiIndex index)
   {
      indexRegister.setDefaultIndex(index);
   }

   /**
    * Create a new index with the same actual context.
    *
    * @return MultiIndex the actual index.
    */
   public MultiIndex createNewIndex(String suffix) throws IOException {

      IndexInfos indexInfos = new IndexInfos();
      IndexUpdateMonitor indexUpdateMonitor = new DefaultIndexUpdateMonitor();
      IndexerIoModeHandler modeHandler = new IndexerIoModeHandler(IndexerIoMode.READ_WRITE);

      MultiIndex newIndex =  new MultiIndex(this, getContext().getIndexingTree(), modeHandler,
              indexInfos, indexUpdateMonitor, cloneDirectoryManager(this.getDirectoryManager(), suffix));

      return newIndex;
   }

   /**
    * @param namespaceMappings
    *            The namespace mappings
    * @return the fulltext indexing configuration or <code>null</code> if there
    *         is no configuration.
    */
   protected IndexingConfiguration createIndexingConfiguration(NamespaceMappings namespaceMappings)
   {
      Element docElement = getIndexingConfigurationDOM();
      if (docElement == null)
      {
         return null;
      }
      try
      {
         IndexingConfiguration idxCfg = indexingConfigurationClass.newInstance();
         idxCfg.init(docElement, getContext(), namespaceMappings);
         return idxCfg;
      }
      catch (Exception e)
      {
         log.warn("Exception initializing indexing configuration from: " + indexingConfigPath, e);
      }
      log.warn(indexingConfigPath + " ignored.");
      return null;
   }

   /**
    * @return the configured synonym provider or <code>null</code> if none is
    *         configured or an error occurs.
    */
   protected SynonymProvider createSynonymProvider()
   {
      SynonymProvider sp = null;
      if (synonymProviderClass != null)
      {
         try
         {
            sp = synonymProviderClass.newInstance();
            sp.initialize(createSynonymProviderConfigResource());
         }
         catch (IOException e)
         {
            log.warn("Exception initializing synonym provider: " + synonymProviderClass, e);
            sp = null;
         }
         catch (InstantiationException e)
         {
            log.warn("Exception initializing synonym provider: " + synonymProviderClass, e);
            sp = null;
         }
         catch (IllegalAccessException e)
         {
            log.warn("Exception initializing synonym provider: " + synonymProviderClass, e);
            sp = null;
         }
      }
      return sp;
   }

   /**
    * @return an initialized {@link DirectoryManager}.
    * @throws IOException
    *             if the directory manager cannot be instantiated or an
    *             exception occurs while initializing the manager.
    */
   protected DirectoryManager createDirectoryManager() throws IOException
   {
      try
      {
         Class<?> clazz = ClassLoading.forName(directoryManagerClass, this);
         if (!DirectoryManager.class.isAssignableFrom(clazz))
         {
            throw new IOException(directoryManagerClass + " is not a DirectoryManager implementation");
         }
         DirectoryManager df = (DirectoryManager)clazz.newInstance();
         df.init(this);
         return df;
      }
      catch (IOException e)
      {
         throw e;
      }
      catch (Exception e)
      {
         IOException ex = new IOException();
         ex.initCause(e);
         throw ex;
      }
   }

   /**
    * Clone the default Index directory manager
    * @return an initialized {@link DirectoryManager}.
    * @throws IOException
    *             if the directory manager cannot be instantiated or an
    *             exception occurs while initializing the manager.
    */
   protected DirectoryManager cloneDirectoryManager(DirectoryManager directoryManager, String suffix) throws IOException
   {
      try
      {
         DirectoryManager df =  directoryManager.getClass().newInstance();
         df.init(this.path + suffix);
         return df;
      }
      catch (IOException e)
      {
         throw e;
      }
      catch (Exception e)
      {
         IOException ex = new IOException();
         ex.initCause(e);
         throw ex;
      }
   }

   /**
    * Creates a file system resource to the synonym provider configuration.
    *
    * @return a file system resource or <code>null</code> if no path was
    *         configured.
    * @throws IOException if an exception occurs accessing the file
    *                             system.
    */
   protected InputStream createSynonymProviderConfigResource() throws IOException
   {
      if (synonymProviderConfigPath != null)
      {
         InputStream fsr;
         // simple sanity check
         String separator = PrivilegedSystemHelper.getProperty("file.separator");
         if (synonymProviderConfigPath.endsWith(PrivilegedSystemHelper.getProperty("file.separator")))
         {
            throw new IOException("Invalid synonymProviderConfigPath: " + synonymProviderConfigPath);
         }

         if (cfm == null)
         {
            int lastSeparator = synonymProviderConfigPath.lastIndexOf(separator);
            if (lastSeparator != -1)
            {
               File root = new File(path, synonymProviderConfigPath.substring(0, lastSeparator));
               fsr =
                  new BufferedInputStream(PrivilegedFileHelper.fileInputStream(new File(root, synonymProviderConfigPath
                     .substring(lastSeparator + 1))));
            }
            else
            {
               fsr = new BufferedInputStream(PrivilegedFileHelper.fileInputStream(new File(synonymProviderConfigPath)));

            }
            synonymProviderConfigFs = fsr;
         }
         else
         {
            try
            {
               fsr = cfm.getInputStream(synonymProviderConfigPath);
            }
            catch (Exception e)
            {
               throw new IOException(e.getLocalizedMessage(), e);
            }
         }
         return fsr;
      }
      else
      {
         // path not configured
         return null;
      }
   }

   /**
    * Creates a spell checker for this query handler.
    * 
    * @return the spell checker or <code>null</code> if none is configured or
    *         an error occurs.
    */
   protected SpellChecker createSpellChecker()
   {
      // spell checker config
      SpellChecker spCheck = null;
      if (spellCheckerClass != null)
      {
         try
         {
            spCheck = spellCheckerClass.newInstance();
            spCheck.init(SearchIndex.this, spellCheckerMinDistance, spellCheckerMorePopular);
         }
         catch (IOException e)
         {
            log.warn("Exception initializing spell checker: " + spellCheckerClass, e);
         }
         catch (InstantiationException e)
         {
            log.warn("Exception initializing spell checker: " + spellCheckerClass, e);
         }
         catch (IllegalAccessException e)
         {
            log.warn("Exception initializing spell checker: " + spellCheckerClass, e);
         }
      }
      return spCheck;
   }

   /**
    * Returns the document element of the indexing configuration or
    * <code>null</code> if there is no indexing configuration.
    * 
    * @return the indexing configuration or <code>null</code> if there is none.
    */
   protected Element getIndexingConfigurationDOM()
   {
      if (indexingConfiguration == null)
      {
         if (indexingConfigPath != null)
         {

            // File config = PrivilegedFileHelper.file(indexingConfigPath);
            SecurityHelper.doPrivilegedAction(new PrivilegedAction<Object>()
            {
               public Object run()
               {
                  InputStream is = SearchIndex.class.getResourceAsStream(indexingConfigPath);
                  if (is == null)
                  {
                     try
                     {
                        is = cfm.getInputStream(indexingConfigPath);
                     }
                     catch (Exception e1)
                     {
                        log.warn("Unable to load configuration " + indexingConfigPath);
                     }
                  }

                  try
                  {
                     DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
                     DocumentBuilder builder = factory.newDocumentBuilder();
                     builder.setEntityResolver(new IndexingConfigurationEntityResolver());
                     String content = Deserializer.resolveVariables(Utils.readStream(is));
                     InputSource source = new InputSource(new StringReader(content));
                     indexingConfiguration = builder.parse(source).getDocumentElement();
                  }
                  catch (ParserConfigurationException e)
                  {
                     log.warn("Unable to create XML parser", e);
                  }
                  catch (IOException e)
                  {
                     log.warn("Exception parsing " + indexingConfigPath, e);
                  }
                  catch (SAXException e)
                  {
                     log.warn("Exception parsing " + indexingConfigPath, e);
                  }
                  return null;
               }
            });
         }
      }
      return indexingConfiguration;
   }

   /**
    * Merges the fulltext indexed fields of the aggregated node states into
    * <code>doc</code>.
    * 
    * @param state
    *            the node state on which <code>doc</code> was created.
    * @param doc
    *            the lucene document with index fields from <code>state</code>.
    * @param loadAllProperties
    *            Indicates whether all the properties should be loaded using the method
    *            {@link ItemDataConsumer#getChildPropertiesData(org.exoplatform.services.jcr.datamodel.NodeData)}
    */
   protected void mergeAggregatedNodeIndexes(NodeData state, Document doc, boolean loadAllProperties, VolatileIndex volatileIndex)
   {
      if (indexingConfig != null)
      {
         AggregateRule[] aggregateRules = indexingConfig.getAggregateRules();
         if (aggregateRules == null)
         {
            return;
         }
         try
         {
            List fulltextTemp = new ArrayList();
            ItemDataConsumer ism = getContext().getItemStateManager();
            for (int i = 0; i < aggregateRules.length; i++)
            {
               boolean ruleMatched = false;
               // node includes
               NodeData[] aggregates = aggregateRules[i].getAggregatedNodeStates(state);
               if (aggregates != null)
               {
                  ruleMatched = true;
                  for (int j = 0; j < aggregates.length; j++)
                  {
                     Document aDoc =
                        createDocument(aggregates[j], getNamespaceMappings(), indexRegister.getDefaultIndex().getIndexFormatVersion(), loadAllProperties);
                     if (volatileIndex != null)
                     {
                        volatileIndex.addAggregateIndexes(aDoc);
                     }
                     // transfer fields to doc if there are any
                     Fieldable[] fulltextFields = aDoc.getFieldables(FieldNames.FULLTEXT);
                     if (fulltextFields != null)
                     {
                        for (int k = 0; k < fulltextFields.length; k++)
                        {
                           for (Fieldable fulltextField : fulltextFields)
                           {
                              doc.add(fulltextField);
                           }
                        }
                        doc.add(new Field(FieldNames.AGGREGATED_NODE_UUID, aggregates[j].getIdentifier(),
                           Field.Store.NO, Field.Index.NOT_ANALYZED_NO_NORMS));
                     }
                  }
                  // make sure that fulltext fields are aligned properly
                  // first all stored fields, then remaining
                  Fieldable[] fulltextFields = doc
                          .getFieldables(FieldNames.FULLTEXT);
                  doc.removeFields(FieldNames.FULLTEXT);
                  Arrays.sort(fulltextFields, FIELDS_COMPARATOR_STORED);
                  for (Fieldable f : fulltextFields)
                  {
                     doc.add(f);
                  }
               }
               // property includes
               PropertyData[] propStates = aggregateRules[i].getAggregatedPropertyStates(state);
               if (propStates != null)
               {
                  ruleMatched = true;
                  for (int j = 0; j < propStates.length; j++)
                  {
                     PropertyData propState = propStates[j];
                     String namePrefix =
                        FieldNames.createNamedValue(getNamespaceMappings()
                           .translateName(propState.getQPath().getName()), "");
                     NodeData parent = (NodeData)ism.getItemData(propState.getParentIdentifier());
                     Document aDoc =
                        createDocument(parent, getNamespaceMappings(), getIndex().getIndexFormatVersion(),
                           loadAllProperties);
                     try
                     {
                        // find the right fields to transfer
                        Fieldable[] fields = aDoc.getFieldables(FieldNames.PROPERTIES);
                        for (int k = 0; k < fields.length; k++)
                        {
                           Fieldable field = fields[k];
                           // assume properties fields use
                           // SingleTokenStream
                           //t = field.tokenStreamValue().next(t);
                           field.tokenStreamValue().incrementToken();
                           CharTermAttribute term = field.tokenStreamValue().getAttribute(CharTermAttribute.class);
                           PayloadAttribute payload = field.tokenStreamValue().getAttribute(PayloadAttribute.class);

                           String value = new String(term.buffer(), 0, term.length());

                           if (value.startsWith(namePrefix))
                           {
                              // extract value
                              value = value.substring(namePrefix.length());
                              // create new named value
                              QPath p = getRelativePath(state, propState);
                              String path = getNamespaceMappings().translatePath(p);
                              value = FieldNames.createNamedValue(path, value);

                              term.setEmpty();
                              term.append(value);
                              doc.add(new Field(field.name(), new SingletonTokenStream(term.toString(), payload
                                 .getPayload())));
                              doc.add(new Field(FieldNames.AGGREGATED_NODE_UUID, parent.getIdentifier(),
                                 Field.Store.NO, Field.Index.NOT_ANALYZED_NO_NORMS));
                           }
                        }
                     }
                     finally
                     {
                        Util.disposeDocument(aDoc);
                     }
                  }
               }

               // only use first aggregate definition that matches
               if (ruleMatched)
               {
                  break;
               }
            }
         }
         catch (Exception e)
         {
            // do not fail if aggregate cannot be created
            log.warn("Exception while building indexing aggregate for" + " node with UUID: " + state.getIdentifier(), e);
         }
      }
   }

   /**
    * Returns the relative path from <code>nodeState</code> to
    * <code>propState</code>.
    * 
    * @param nodeState
    *            a node state.
    * @param propState
    *            a property state.
    * @return the relative path.
    * @throws RepositoryException
    *             if an error occurs while resolving paths.
    */
   protected QPath getRelativePath(NodeData nodeState, PropertyData propState) throws RepositoryException
   {
      throw new RepositoryException();
   }

   /**
    * Retrieves the root of the indexing aggregate for <code>state</code> and
    * puts it into <code>map</code>.
    * 
    * @param state
    *            the node state for which we want to retrieve the aggregate
    *            root.
    * @param map
    *            aggregate roots are collected in this map. Key=UUID,
    *            value=NodeState.
    */
   protected void retrieveAggregateRoot(NodeData state, Map<String, NodeData> map)
   {
      if (indexingConfig != null)
      {
         AggregateRule[] aggregateRules = indexingConfig.getAggregateRules();
         if (aggregateRules == null)
         {
            return;
         }
         try
         {
            for (int i = 0; i < aggregateRules.length; i++)
            {
               NodeData root = aggregateRules[i].getAggregateRoot(state);
               if (root != null)
               {
                  map.put(root.getIdentifier(), root);
               }
            }
         }
         catch (Exception e)
         {
            log.warn("Unable to get aggregate root for " + state.getIdentifier(), e);
         }
      }
   }

   /**
    * Retrieves the root of the indexing aggregate for
    * <code>removedUUIDs</code> and puts it into <code>map</code>.
    * 
    * @param removedNodeIds
    *            the UUIDs of removed nodes.
    * @param map
    *            aggregate roots are collected in this map. Key=UUID,
    *            value=NodeState.
    */
   protected void retrieveAggregateRoot(final Set<String> removedNodeIds, final Map<String, NodeData> map)
   {
      if (indexingConfig != null)
      {
         AggregateRule[] aggregateRules = indexingConfig.getAggregateRules();
         if (aggregateRules == null)
         {
            return;
         }
         long time = 0;
         if (log.isDebugEnabled())
         {
            time = System.currentTimeMillis();
         }
         int found = SecurityHelper.doPrivilegedAction(new PrivilegedAction<Integer>()
         {
            public Integer run()
            {
               int found = 0;
               try
               {
                  CachingMultiIndexReader reader = indexRegister.getDefaultIndex().getIndexReader();
                  try
                  {
                     Term aggregateUUIDs = new Term(FieldNames.AGGREGATED_NODE_UUID, "");
                     TermDocs tDocs = reader.termDocs();
                     try
                     {
                        ItemDataConsumer ism = getContext().getItemStateManager();
                        for (Iterator<String> it = removedNodeIds.iterator(); it.hasNext();)
                        {
                           String id = it.next();
                           aggregateUUIDs = aggregateUUIDs.createTerm(id);
                           tDocs.seek(aggregateUUIDs);
                           while (tDocs.next())
                           {
                              Document doc = reader.document(tDocs.doc(), FieldSelectors.UUID);
                              String uuid = doc.get(FieldNames.UUID);
                              ItemData itd = ism.getItemData(uuid);
                              if (itd == null)
                              {
                                 continue;
                              }
                              if (!itd.isNode())
                              {
                                 throw new RepositoryException("Item with id:" + uuid + " is not a node");
                              }
                              map.put(uuid, (NodeData)itd);
                              found++;
                           }
                        }
                     }
                     finally
                     {
                        tDocs.close();
                     }
                  }
                  finally
                  {
                     reader.release();
                  }
               }
               catch (Exception e)
               {
                  log.warn("Exception while retrieving aggregate roots", e);
               }
               return found;
            }
         });
         if (log.isDebugEnabled())
         {
            time = System.currentTimeMillis() - time;
            log.debug("Retrieved {} aggregate roots in {} ms.", new Integer(found), new Long(time));
         }
      }
   }

   // ----------------------------< internal
   // >----------------------------------

   /**
    * Combines multiple {@link CachingMultiIndexReader} into a
    * <code>MultiReader</code> with {@link HierarchyResolver} support.
    */
   protected static final class CombinedIndexReader extends MultiReader implements HierarchyResolver, MultiIndexReader
   {

      /**
       * The sub readers.
       */
      private final CachingMultiIndexReader[] subReaders;

      /**
       * Doc number starts for each sub reader
       */
      private int[] starts;

      public CombinedIndexReader(CachingMultiIndexReader[] indexReaders)
      {
         super(indexReaders);
         this.subReaders = indexReaders;
         this.starts = new int[subReaders.length + 1];

         int maxDoc = 0;
         for (int i = 0; i < subReaders.length; i++)
         {
            starts[i] = maxDoc;
            maxDoc += subReaders[i].maxDoc();
         }
         starts[subReaders.length] = maxDoc;
      }

      /**
       * {@inheritDoc}
       */
      public int[] getParents(int n, int[] docNumbers) throws IOException
      {
         int i = readerIndex(n);
         DocId id = subReaders[i].getParentDocId(n - starts[i]);
         id = id.applyOffset(starts[i]);
         return id.getDocumentNumbers(this, docNumbers);
      }

      // -------------------------< MultiIndexReader
      // >-------------------------

      /**
       * {@inheritDoc}
       */
      public IndexReader[] getIndexReaders()
      {
         IndexReader[] readers = new IndexReader[subReaders.length];
         System.arraycopy(subReaders, 0, readers, 0, subReaders.length);
         return readers;
      }

      /**
       * {@inheritDoc}
       */
      public void release() throws IOException
      {
         for (int i = 0; i < subReaders.length; i++)
         {
            subReaders[i].release();
         }
      }

      // ---------------------------< internal
      // >-------------------------------

      @Override
      public boolean equals(Object obj)
      {
         if (obj instanceof CombinedIndexReader)
         {
            CombinedIndexReader other = (CombinedIndexReader)obj;
            return Arrays.equals(subReaders, other.subReaders);
         }
         return false;
      }

      @Override
      public int hashCode()
      {
         int hash = 0;
         for (int i = 0; i < subReaders.length; i++)
         {
            hash = 31 * hash + subReaders[i].hashCode();
         }
         return hash;
      }

      /**
       * {@inheritDoc}
       */
      public ForeignSegmentDocId createDocId(String uuid) throws IOException
      {
         for (int i = 0; i < subReaders.length; i++)
         {
            CachingMultiIndexReader subReader = subReaders[i];
            ForeignSegmentDocId doc = subReader.createDocId(uuid);
            if (doc != null)
            {
               return doc;
            }
         }
         return null;
      }

      /**
       * {@inheritDoc}
       */
      public int getDocumentNumber(ForeignSegmentDocId docId)
      {
         for (int i = 0; i < subReaders.length; i++)
         {
            CachingMultiIndexReader subReader = subReaders[i];
            int realDoc = subReader.getDocumentNumber(docId);
            if (realDoc >= 0)
            {
               return realDoc + starts[i];
            }
         }
         return -1;
      }
   }

   // --------------------------< properties
   // >----------------------------------

   /**
    * Sets the analyzer in use for indexing. The given analyzer class name must
    * satisfy the following conditions:
    * <ul>
    * <li>the class must exist in the class path</li>
    * <li>the class must have a public default constructor</li>
    * <li>the class must be a Lucene Analyzer</li>
    * </ul>
    * <p>
    * If the above conditions are met, then a new instance of the class is set
    * as the analyzer. Otherwise a warning is logged and the current analyzer
    * is not changed.
    * <p>
    * This property setter method is normally invoked by the Jackrabbit
    * configuration mechanism if the "analyzer" parameter is set in the search
    * configuration.
    * 
    * @param analyzerClassName
    *            the analyzer class name
    */
   public void setAnalyzer(String analyzerClassName)
   {
      try
      {
         Class<?> analyzerClass = ClassLoading.forName(analyzerClassName, this);
         analyzer.setDefaultAnalyzer((Analyzer)analyzerClass.newInstance());
      }
      catch (ClassNotFoundException e)
      {
         log.warn("Invalid Analyzer class: " + analyzerClassName, e);
      }
      catch (InstantiationException e)
      {
         log.warn("Invalid Analyzer class: " + analyzerClassName, e);
      }
      catch (IllegalAccessException e)
      {
         log.warn("Invalid Analyzer class: " + analyzerClassName, e);
      }
   }

   /**
    * Returns the class name of the analyzer that is currently in use.
    * 
    * @return class name of analyzer in use.
    */
   public String getAnalyzer()
   {
      return analyzer.getClass().getName();
   }

   /**
    * Sets the location of the search index.
    * 
    * @param path
    *            the location of the search index.
    */
   public void setPath(String path)
   {

      this.path = path.replace("${java.io.tmpdir}", PrivilegedSystemHelper.getProperty("java.io.tmpdir"));

   }

   /**
    * Returns the location of the search index. Returns <code>null</code> if
    * not set.
    * 
    * @return the location of the search index.
    */
   public String getPath()
   {
      return path;
   }

   /**
    * The lucene index writer property: useCompoundFile
    */
   public void setUseCompoundFile(boolean b)
   {
      useCompoundFile = b;
   }

   /**
    * Returns the current value for useCompoundFile.
    * 
    * @return the current value for useCompoundFile.
    */
   public boolean getUseCompoundFile()
   {
      return useCompoundFile;
   }

   /**
    * The lucene index writer property: minMergeDocs
    */
   public void setMinMergeDocs(int minMergeDocs)
   {
      this.minMergeDocs = minMergeDocs;
   }

   /**
    * Returns the current value for minMergeDocs.
    * 
    * @return the current value for minMergeDocs.
    */
   public int getMinMergeDocs()
   {
      return minMergeDocs;
   }

   /**
    * Sets the property: volatileIdleTime
    * 
    * @param volatileIdleTime
    *            idle time in seconds
    */
   public void setVolatileIdleTime(int volatileIdleTime)
   {
      this.volatileIdleTime = volatileIdleTime;
   }

   /**
    * Returns the current value for volatileIdleTime.
    * 
    * @return the current value for volatileIdleTime.
    */
   public int getVolatileIdleTime()
   {
      return volatileIdleTime;
   }

   /**
    * The lucene index writer property: maxMergeDocs
    */
   public void setMaxMergeDocs(int maxMergeDocs)
   {
      this.maxMergeDocs = maxMergeDocs;
   }

   /**
    * Returns the current value for maxMergeDocs.
    * 
    * @return the current value for maxMergeDocs.
    */
   public int getMaxMergeDocs()
   {
      return maxMergeDocs;
   }

   /**
    * The lucene index writer property: mergeFactor
    */
   public void setMergeFactor(int mergeFactor)
   {
      this.mergeFactor = mergeFactor;
   }

   /**
    * Returns the current value for the merge factor.
    * 
    * @return the current value for the merge factor.
    */
   public int getMergeFactor()
   {
      return mergeFactor;
   }

   /**
    * @see VolatileIndex#setBufferSize(int)
    */
   public void setBufferSize(int size)
   {
      bufferSize = size;
   }

   /**
    * Returns the current value for the buffer size.
    * 
    * @return the current value for the buffer size.
    */
   public int getBufferSize()
   {
      return bufferSize;
   }

   public void setRespectDocumentOrder(boolean docOrder)
   {
      documentOrder = docOrder;
   }

   public boolean getRespectDocumentOrder()
   {
      return documentOrder;
   }

   public void setForceConsistencyCheck(boolean b)
   {
      forceConsistencyCheck = b;
   }

   public boolean getForceConsistencyCheck()
   {
      return forceConsistencyCheck;
   }

   public void setAutoRepair(boolean b)
   {
      autoRepair = b;
   }

   public boolean getAutoRepair()
   {
      return autoRepair;
   }

   public void setCacheSize(int size)
   {
      cacheSize = size;
   }

   public int getCacheSize()
   {
      return cacheSize;
   }

   public void setMaxFieldLength(int length)
   {
      maxFieldLength = length;
   }

   public int getMaxFieldLength()
   {
      return maxFieldLength;
   }

   /**
    * Tells the query handler how many result should be fetched initially when
    * a query is executed.
    * 
    * @param size
    *            the number of results to fetch initially.
    */
   public void setResultFetchSize(int size)
   {
      resultFetchSize = size;
   }

   /**
    * @return the number of results the query handler will fetch initially when
    *         a query is executed.
    */
   public int getResultFetchSize()
   {
      return resultFetchSize;
   }

   /**
    * The number of background threads for the extractor pool.
    * 
    * @param numThreads
    *            the number of threads.
    */
   public void setExtractorPoolSize(int numThreads)
   {
      if (numThreads < 0)
      {
         numThreads = 0;
      }
      extractorPoolSize = numThreads;
   }

   /**
    * @return the size of the thread pool which is used to run the text
    *         extractors when binary content is indexed.
    */
   public int getExtractorPoolSize()
   {
      return extractorPoolSize;
   }

   /**
    * The number of extractor jobs that are queued until a new job is executed
    * with the current thread instead of using the thread pool.
    * 
    * @param backLog
    *            size of the extractor job queue.
    */
   public void setExtractorBackLogSize(int backLog)
   {
      extractorBackLog = backLog;
   }

   /**
    * @return the size of the extractor queue back log.
    */
   public int getExtractorBackLogSize()
   {
      return extractorBackLog;
   }

   /**
    * The timeout in milliseconds which is granted to the text extraction
    * process until fulltext indexing is deferred to a background thread.
    * 
    * @param timeout
    *            the timeout in milliseconds.
    */
   public void setExtractorTimeout(long timeout)
   {
      extractorTimeout = timeout;
   }

   /**
    * @return the extractor timeout in milliseconds.
    */
   public long getExtractorTimeout()
   {
      return extractorTimeout;
   }

   /**
    * If set to <code>true</code> additional information is stored in the index
    * to support highlighting using the rep:excerpt pseudo property.
    * 
    * @param b
    *            <code>true</code> to enable highlighting support.
    */
   public void setSupportHighlighting(boolean b)
   {
      supportHighlighting = b;
   }

   /**
    * @return <code>true</code> if highlighting support is enabled.
    */
   public boolean getSupportHighlighting()
   {
      return supportHighlighting;
   }

   /**
    * Sets the class name for the {@link ExcerptProvider} that should be used
    * for the rep:excerpt pseudo property in a query.
    * 
    * @param className
    *            the name of a class that implements {@link ExcerptProvider}.
    */
   @SuppressWarnings("unchecked")
   public void setExcerptProviderClass(String className)
   {
      try
      {
         Class<?> clazz = ClassLoading.forName(className, this);
         if (ExcerptProvider.class.isAssignableFrom(clazz))
         {
            excerptProviderClass = (Class<? extends ExcerptProvider>)clazz;
         }
         else
         {
            log.warn("Invalid value for excerptProviderClass, {} does " + "not implement ExcerptProvider interface.",
               className);
         }
      }
      catch (ClassNotFoundException e)
      {
         log.warn("Invalid value for excerptProviderClass, class {} not found.", className);
      }
   }

   /**
    * @return the class name of the excerpt provider implementation.
    */
   public String getExcerptProviderClass()
   {
      return excerptProviderClass.getName();
   }

   /**
    * Sets the path to the indexing configuration file.
    * 
    * @param path
    *            the path to the configuration file.
    */
   public void setIndexingConfiguration(String path)
   {
      indexingConfigPath = path;
   }

   /**
    * @return the path to the indexing configuration file.
    */
   public String getIndexingConfiguration()
   {
      return indexingConfigPath;
   }

   /**
    * Sets the name of the class that implements {@link IndexingConfiguration}.
    * The default value is
    * <code>org.apache.jackrabbit.core.query.lucene.IndexingConfigurationImpl</code>
    * .
    * 
    * @param className
    *            the name of the class that implements
    *            {@link IndexingConfiguration}.
    */
   @SuppressWarnings("unchecked")
   public void setIndexingConfigurationClass(String className)
   {
      try
      {
         Class<?> clazz = ClassLoading.forName(className, this);
         if (IndexingConfiguration.class.isAssignableFrom(clazz))
         {
            indexingConfigurationClass = (Class<? extends IndexingConfiguration>)clazz;
         }
         else
         {
            log.warn("Invalid value for indexingConfigurationClass, {} "
               + "does not implement IndexingConfiguration interface.", className);
         }
      }
      catch (ClassNotFoundException e)
      {
         log.warn("Invalid value for indexingConfigurationClass, class {} not found.", className);
      }
   }

   /**
    * @return the class name of the indexing configuration implementation.
    */
   public String getIndexingConfigurationClass()
   {
      return indexingConfigurationClass.getName();
   }

   /**
    * Sets the name of the class that implements {@link SynonymProvider}. The
    * default value is <code>null</code> (none set).
    * 
    * @param className
    *            name of the class that implements {@link SynonymProvider}.
    */
   @SuppressWarnings("unchecked")
   public void setSynonymProviderClass(String className)
   {
      try
      {
         Class<?> clazz = ClassLoading.forName(className, this);
         if (SynonymProvider.class.isAssignableFrom(clazz))
         {
            synonymProviderClass = (Class<? extends SynonymProvider>)clazz;
         }
         else
         {
            log.warn("Invalid value for synonymProviderClass, {} " + "does not implement SynonymProvider interface.",
               className);
         }
      }
      catch (ClassNotFoundException e)
      {
         log.warn("Invalid value for synonymProviderClass, class {} not found.", className);
      }
   }

   /**
    * @return the class name of the synonym provider implementation or
    *         <code>null</code> if none is set.
    */
   public String getSynonymProviderClass()
   {
      if (synonymProviderClass != null)
      {
         return synonymProviderClass.getName();
      }
      else
      {
         return null;
      }
   }

   /**
    * Sets the name of the class that implements {@link SpellChecker}. The
    * default value is <code>null</code> (none set).
    * 
    * @param className
    *            name of the class that implements {@link SpellChecker}.
    */
   @SuppressWarnings("unchecked")
   public void setSpellCheckerClass(String className)
   {
      try
      {
         Class<?> clazz = ClassLoading.forName(className, this);
         if (SpellChecker.class.isAssignableFrom(clazz))
         {
            spellCheckerClass = (Class<? extends SpellChecker>)clazz;
         }
         else
         {
            log.warn("Invalid value for spellCheckerClass, {} " + "does not implement SpellChecker interface.",
               className);
         }
      }
      catch (ClassNotFoundException e)
      {
         log.warn("Invalid value for spellCheckerClass," + " class {} not found.", className);
      }
   }

   /**
    * Set SpellChecker morePopular parameter.
    * @param morePopular boolean
    */
   public void setSpellCheckerMorePopuar(boolean morePopular)
   {
      spellCheckerMorePopular = morePopular;
   }

   /**
    * Set SpellChecker minimal word distance.
    * @param minDistance float
    */
   public void setSpellCheckerMinDistance(float minDistance)
   {
      spellCheckerMinDistance = minDistance;
   }

   /**
    * @return the class name of the spell checker implementation or
    *         <code>null</code> if none is set.
    */
   public String getSpellCheckerClass()
   {
      if (spellCheckerClass != null)
      {
         return spellCheckerClass.getName();
      }
      else
      {
         return null;
      }
   }

   /**
    * Enables or disables the consistency check on startup. Consistency checks
    * are disabled per default.
    * 
    * @param b
    *            <code>true</code> enables consistency checks.
    * @see #setForceConsistencyCheck(boolean)
    */
   public void setEnableConsistencyCheck(boolean b)
   {
      this.consistencyCheckEnabled = b;
   }

   /**
    * @return <code>true</code> if consistency checks are enabled.
    */
   public boolean getEnableConsistencyCheck()
   {
      return consistencyCheckEnabled;
   }

   /**
    * Sets the configuration path for the synonym provider.
    * 
    * @param path
    *            the configuration path for the synonym provider.
    */
   public void setSynonymProviderConfigPath(String path)
   {
      synonymProviderConfigPath = path;
   }

   /**
    * @return the configuration path for the synonym provider. If none is set
    *         this method returns <code>null</code>.
    */
   public String getSynonymProviderConfigPath()
   {
      return synonymProviderConfigPath;
   }

   /**
    * Sets the similarity implementation, which will be used for indexing and
    * searching. The implementation must extend {@link Similarity}.
    * 
    * @param className
    *            a {@link Similarity} implementation.
    */
   public void setSimilarityClass(String className)
   {
      try
      {
         Class<?> similarityClass = ClassLoading.forName(className, this);
         similarity = (Similarity)similarityClass.newInstance();
      }
      catch (ClassNotFoundException e)
      {
         log.warn("Invalid Similarity class: " + className, e);
      }
      catch (InstantiationException e)
      {
         log.warn("Invalid Similarity class: " + className, e);
      }
      catch (IllegalAccessException e)
      {
         log.warn("Invalid Similarity class: " + className, e);
      }
   }

   /**
    * @return the name of the similarity class.
    */
   public String getSimilarityClass()
   {
      return similarity.getClass().getName();
   }

   /**
    * Sets a new maxVolatileIndexSize value.
    * 
    * @param maxVolatileIndexSize
    *            the new value.
    */
   public void setMaxVolatileIndexSize(long maxVolatileIndexSize)
   {
      this.maxVolatileIndexSize = maxVolatileIndexSize;
   }

   /**
    * @return the maxVolatileIndexSize in bytes.
    */
   public long getMaxVolatileIndexSize()
   {
      return maxVolatileIndexSize;
   }

   /**
    * @return maxVolatileTime in seconds
    */
   public int getMaxVolatileTime()
   {
      return maxVolatileTime;
   }

   /**
    * @param maxVolatileTime in seconds
    */
   public void setMaxVolatileTime(int maxVolatileTime)
   {
      this.maxVolatileTime = maxVolatileTime;
   }

   /**
    * @return the name of the directory manager class.
    */
   public String getDirectoryManagerClass()
   {
      return directoryManagerClass;
   }

   /**
    * Sets name of the directory manager class. The class must implement
    * {@link DirectoryManager}.
    * 
    * @param className
    *            the name of the class that implements directory manager.
    */
   public void setDirectoryManagerClass(String className)
   {
      this.directoryManagerClass = className;
   }

   /**
    * @return the current value for termInfosIndexDivisor.
    */
   public int getTermInfosIndexDivisor()
   {
      return termInfosIndexDivisor;
   }

   /**
    * @return the current value for reindexingPageSize
    */
   public int getReindexingPageSize()
   {
      return reindexingPageSize;
   }

   /**
    * @return the current value for rdbmsReindexing
    */
   public boolean isRDBMSReindexing()
   {
      return rdbmsReindexing;
   }

   /**
    * @return the current value for asyncReindexing
    */
   public boolean isAsyncReindexing()
   {
      return asyncReindexing;
   }

   /** 
    * @return the current value for indexRecoveryMode 
    */
   public String getIndexRecoveryMode()
   {
      return indexRecoveryMode;
   }

   /**
    * @return the current value for indexRecoveryStrategy
    */
   public String getIndexRecoveryStrategy()
   {
      return indexRecoveryStrategy;
   }

   public void setIndexRecoveryStrategy(String indexRecoveryStrategy)
   {
      this.indexRecoveryStrategy = indexRecoveryStrategy;
   }

   public RSyncConfiguration getRsyncConfiguration()
   {
      return rsyncConfiguration;
   }

   public void setRsyncConfiguration(RSyncConfiguration rsyncConfiguration)
   {
      this.rsyncConfiguration = rsyncConfiguration;
   }

   /**
    * Sets a new value for termInfosIndexDivisor.
    * 
    * @param termInfosIndexDivisor
    *            the new value.
    */
   public void setTermInfosIndexDivisor(int termInfosIndexDivisor)
   {
      this.termInfosIndexDivisor = termInfosIndexDivisor;
   }

   /**
    * @return <code>true</code> if the hierarchy cache should be initialized
    *         immediately on startup.
    */
   public boolean isInitializeHierarchyCache()
   {
      return initializeHierarchyCache;
   }

   /**
    * Whether the hierarchy cache should be initialized immediately on startup.
    * 
    * @param initializeHierarchyCache
    *            <code>true</code> if the cache should be initialized
    *            immediately.
    */
   public void setInitializeHierarchyCache(boolean initializeHierarchyCache)
   {
      this.initializeHierarchyCache = initializeHierarchyCache;
   }

   /**
    * Set a new value for reindexingPageSize.
    * 
    * @param reindexingPageSize
    *            the new value
    */
   public void setReindexingPageSize(int reindexingPageSize)
   {
      this.reindexingPageSize = reindexingPageSize;
   }

   /**
    * Set a new value for reindexingPageSize.
    * 
    * @param rdbmsReindexing
    *            the new value
    */
   public void setRDBMSReindexing(boolean rdbmsReindexing)
   {
      this.rdbmsReindexing = rdbmsReindexing;
   }

   /**
    *  Set a new value for indexRecoveryMode. 
    * 
    * @param indexRecoveryMode 
    *          the new value for indexRecoveryMode
    */
   public void setIndexRecoveryMode(String indexRecoveryMode)
   {
      this.indexRecoveryMode = indexRecoveryMode;
   }

   /**
    *  Set a new value for asyncReindexing. 
    * 
    * @param asyncReindexing
    *          the new value for asyncReindexing
    */
   public void setAsyncReindexing(boolean asyncReindexing)
   {
      this.asyncReindexing = asyncReindexing;
   }

   // ----------------------------< internal
   // >----------------------------------

   /**
    * Checks if this <code>SearchIndex</code> is open, otherwise throws an
    * <code>IOException</code>.
    * 
    * @throws IOException
    *             if this <code>SearchIndex</code> had been closed.
    */
   private void checkOpen() throws IOException
   {
      if (closed.get())
      {
         throw new IOException("query handler closed and cannot be used anymore.");
      }
   }

   private static final Comparator<Fieldable> FIELDS_COMPARATOR_STORED = new Comparator<Fieldable>()
   {
      public int compare(Fieldable o1, Fieldable o2)
      {
         return Boolean.valueOf(o2.isStored()).compareTo(o1.isStored());
      }
   };

   /**
    * Log unindexed changes into error.log
    * 
    * @param removed
    *            set of removed node uuids
    * @param added
    *            map of added node states and uuids
    * @throws IOException
    */
   public void logErrorChanges(Set<String> removed, Set<String> added) throws IOException
   {
      logErrorChanges(errorLog, removed, added);
   }

   /**
    * Log unindexed changes into error.log
    *
    * @param removed
    *            set of removed node uuids
    * @param added
    *            map of added node states and uuids
    * @throws IOException
    */
   public void logErrorChanges(ErrorLog errorLog, Set<String> removed, Set<String> added) throws IOException
   {
      // backup the remove and add iterators
      if(errorLog != null)
      {
         errorLog.writeChanges(removed, added);
      }
   }

   /**
    * Initialization error log.
    */
   public ErrorLog doInitErrorLog(String path) throws IOException
   {
      File file = new File(new File(path), ERROR_LOG);
      return new ErrorLog(file, errorLogfileSize);
   }

   private void recoverErrorLog(ErrorLog errlog) throws IOException, RepositoryException
   {
      final Set<String> rem = new HashSet<String>();
      final Set<String> add = new HashSet<String>();

      errlog.readChanges(rem, add);

      // check is any notifies in log
      if (rem.isEmpty() && add.isEmpty())
      {
         // there is no sense to continue
         return;
      }

      Iterator<String> removedStates = rem.iterator();

      // make a new iterator;
      Iterator<NodeData> addedStates = new Iterator<NodeData>()
      {
         private final Iterator<String> iter = add.iterator();

         public boolean hasNext()
         {
            return iter.hasNext();
         }

         public NodeData next()
         {
            String id;
            // we have to iterrate through items till will meet ones
            // existing in
            // workspace
            while (iter.hasNext())
            {
               id = iter.next();

               try
               {
                  ItemData item = getContext().getItemStateManager().getItemData(id);
                  if (item != null)
                  {
                     if (item.isNode())
                     {
                        return (NodeData)item; // return node here
                     }
                     else
                     {
                        log.warn("Node expected but property found with id " + id + ". Skipping "
                           + item.getQPath().getAsString());
                     }
                  }
                  else
                  {
                     log.warn("Unable to recovery node index " + id + ". Node not found.");
                  }
               }
               catch (RepositoryException e)
               {
                  log.error("ErrorLog recovery error. Item id " + id + ". " + e, e);
               }
            }

            return null;
         }

         public void remove()
         {
            throw new UnsupportedOperationException();
         }
      };

      updateNodes(removedStates, addedStates);

      errlog.clear();
   }

   /**
    *
    */
   public QueryHits executeQuery(Query query) throws IOException
   {
      waitForResuming();

      checkOpen();

      workingThreads.incrementAndGet();

      try
      {
         IndexReader reader = getIndexReader(true);
         IndexSearcher searcher = new IndexSearcher(reader);
         searcher.setSimilarity(getSimilarity());

         return new LuceneQueryHits(reader, searcher, query, true);
      }
      finally
      {
         workingThreads.decrementAndGet();

         if (isSuspended.get() && workingThreads.get() == 0)
         {
            synchronized (workingThreads)
            {
               workingThreads.notifyAll();
            }
         }
      }
   }

   /**
    * {@inheritDoc}
    */
   public void onChangeMode(IndexerIoMode mode)
   {
      try
      {
         if (mode == IndexerIoMode.READ_WRITE)
         {
            // reprocess any notfinished notifies;
            log.info("Processing error log ...");
            recoverErrorLog(errorLog);
         }
      }
      catch (IOException e)
      {
         log.error("Can not recover error log. On changed mode " + mode, e);
      }
      catch (RepositoryException e)
      {
         log.error("Can not recover error log.", e);
      }
   }

   /**
    * @see org.exoplatform.services.jcr.impl.core.query.QueryHandler#setOnline(boolean, boolean, boolean)
    */
   public void setOnline(boolean isOnline, boolean allowQuery, boolean dropStaleIndexes) throws IOException
   {
      checkOpen();
      if (isOnline)
      {
         this.allowQuery.set(true);
      }
      else
      {
         this.allowQuery.set(allowQuery);
      }
      indexRegister.getDefaultIndex().setOnline(isOnline, dropStaleIndexes);
   }

   /**
    * @see org.exoplatform.services.jcr.impl.core.query.QueryHandler#isOnline()
    */
   public boolean isOnline()
   {
      return indexRegister.getDefaultIndex().isOnline();
   }

   /**
    * {@inheritDoc}
    */
   public void suspend() throws SuspendException
   {
      latcher.set(new CountDownLatch(1));
      isSuspended.set(true);

      if (workingThreads.get() > 0)
      {
         synchronized (workingThreads)
         {
            while (workingThreads.get() > 0)
            {
               try
               {
                  workingThreads.wait();
               }
               catch (InterruptedException e)
               {
                  if (log.isTraceEnabled())
                  {
                     log.trace(e.getMessage(), e);
                  }
               }
            }
         }
      }

      closeAndKeepWaitingThreads(false);
   }

   /**
    * {@inheritDoc}
    */
   public void resume() throws ResumeException
   {
      try
      {
         closed.set(false);
         doInit();

         resumeWaitingThreads();

         isSuspended.set(false);
      }
      catch (IOException e)
      {
         throw new ResumeException(e);
      }
      catch (RepositoryException e)
      {
         throw new ResumeException(e);
      }
   }

   /**
    * {@inheritDoc}
    */
   public boolean isSuspended()
   {
      return isSuspended.get();
   }

   /**
    * If component is suspended need to wait resuming and not allow
    * execute query on closed index.
    * 
    * @throws IOException
    */
   void waitForResuming() throws IOException
   {
      if (isSuspended.get())
      {
         try
         {
            latcher.get().await();
         }
         catch (InterruptedException e)
         {
            throw new IOException(e);
         }
      }
   }

   /**
    * Count down latcher which makes for resuming all
    * waiting threads.
    */
   private void resumeWaitingThreads()
   {
      if (latcher.get() != null)
      {
         latcher.get().countDown();
      }
   }

   /**
    * @return the indexingThreadPoolSize
    */
   public Integer getIndexingThreadPoolSize()
   {
      return indexingThreadPoolSize;
   }

   /**
    * @param indexingThreadPoolSize the indexingThreadPoolSize to set
    */
   public void setIndexingThreadPoolSize(Integer indexingThreadPoolSize)
   {
      this.indexingThreadPoolSize = indexingThreadPoolSize;
   }

   /**
    * @return the indexingLoadBatchingThresholdDynamic
    */
   public boolean isIndexingLoadBatchingThresholdDynamic()
   {
      return indexingLoadBatchingThresholdDynamic;
   }

   /**
    * @param indexingLoadBatchingThresholdDynamic the indexingLoadBatchingThresholdDynamic to set
    */
   public void setIndexingLoadBatchingThresholdDynamic(boolean indexingLoadBatchingThresholdDynamic)
   {
      this.indexingLoadBatchingThresholdDynamic = indexingLoadBatchingThresholdDynamic;
   }

   /**
    * @return the indexingLoadBatchingThresholdTTL
    */
   public long getIndexingLoadBatchingThresholdTTL()
   {
      return indexingLoadBatchingThresholdTTL;
   }

   /**
    * @param indexingLoadBatchingThresholdTTL the indexingLoadBatchingThresholdTTL to set
    */
   public void setIndexingLoadBatchingThresholdTTL(long indexingLoadBatchingThresholdTTL)
   {
      this.indexingLoadBatchingThresholdTTL = indexingLoadBatchingThresholdTTL;
   }

   /**
    * @return the indexingLoadBatchingThresholdProperty
    */
   public int getIndexingLoadBatchingThresholdProperty()
   {
      return indexingLoadBatchingThresholdProperty;
   }

   /**
    * @param indexingLoadBatchingThresholdProperty the indexingLoadBatchingThresholdProperty to set
    */
   public void setIndexingLoadBatchingThresholdProperty(int indexingLoadBatchingThresholdProperty)
   {
      this.indexingLoadBatchingThresholdProperty = indexingLoadBatchingThresholdProperty;
   }

   /**
    * @return the indexingLoadBatchingThresholdNode
    */
   public int getIndexingLoadBatchingThresholdNode()
   {
      return indexingLoadBatchingThresholdNode;
   }

   /**
    * @param indexingLoadBatchingThresholdNode the indexingLoadBatchingThresholdNode to set
    */
   public void setIndexingLoadBatchingThresholdNode(int indexingLoadBatchingThresholdNode)
   {
      this.indexingLoadBatchingThresholdNode = indexingLoadBatchingThresholdNode;
   }

   /**
    * {@inheritDoc}
    */
   public int getPriority()
   {
      return PRIORITY_NORMAL;
   }

   public IndexRegister getIndexRegister()
   {
      return indexRegister;
   }

   /**
    * Internal class used to allow dynamic register/unregister d'index
    * On the actual SearchIndex component
    */
   public class IndexRegister
   {
      //List of registered index
      private final Map<MultiIndex, ErrorLog> indexList = new HashMap();

      //default index
      private MultiIndex defaultIndex ;

      public  IndexRegister(MultiIndex defaultIndex)
      {
         this.defaultIndex = defaultIndex;
      }

      public void register(MultiIndex index, ErrorLog errorLog) throws IOException
      {
         indexList.put(index, errorLog);
      }

      public void unregister(MultiIndex multiIndex) throws IOException
      {
         multiIndex.close();
         ErrorLog errorLog =indexList.get(multiIndex);
         errorLog.flush();
         errorLog.close();
         indexList.remove(multiIndex);
      }

      public Set<MultiIndex> getIndexList()
      {
         return indexList.keySet();
      }

      public ErrorLog getErrorLogs(MultiIndex index)
      {
         return indexList.get(index);
      }

      public MultiIndex getDefaultIndex()
      {
         return defaultIndex;
      }

      public  void setDefaultIndex(MultiIndex index)
      {
         this.defaultIndex = index;
      }

   }
}
