001    /*
002     * Copyright (C) 2012 eXo Platform SAS.
003     *
004     * This is free software; you can redistribute it and/or modify it
005     * under the terms of the GNU Lesser General Public License as
006     * published by the Free Software Foundation; either version 2.1 of
007     * the License, or (at your option) any later version.
008     *
009     * This software is distributed in the hope that it will be useful,
010     * but WITHOUT ANY WARRANTY; without even the implied warranty of
011     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012     * Lesser General Public License for more details.
013     *
014     * You should have received a copy of the GNU Lesser General Public
015     * License along with this software; if not, write to the Free
016     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018     */
019    
020    package org.crsh.plugin;
021    
022    import org.crsh.util.TypeResolver;
023    import org.slf4j.Logger;
024    import org.slf4j.LoggerFactory;
025    
026    import java.util.ArrayList;
027    import java.util.Collections;
028    import java.util.List;
029    
030    public abstract class CRaSHPlugin<P> {
031    
032      /** . */
033      protected final Logger log = LoggerFactory.getLogger(getClass());
034    
035      /** . */
036      public static final int FAILED = -1;
037    
038      /** . */
039      public static final int CONSTRUCTED = 0;
040    
041      /** . */
042      public static final int INITIALIZING = 1;
043    
044      /** . */
045      public static final int INITIALIZED = 2;
046    
047      /** . */
048      PluginContext context;
049    
050      /** . */
051      int status;
052    
053      /** . */
054      private final Class<P> type;
055    
056      /** . */
057      private List<PropertyDescriptor<?>> configurationCapabilities;
058    
059      protected CRaSHPlugin() {
060        this.type = (Class<P>)TypeResolver.resolveToClass(getClass(), CRaSHPlugin.class, 0);
061        this.status = CONSTRUCTED;
062        this.context = null;
063      }
064    
065      protected final PluginContext getContext() {
066        return context;
067      }
068    
069      /**
070       * Returns the current plugin status.
071       *
072       * @return the plugin status
073       */
074      public int getStatus() {
075        return status;
076      }
077    
078      /**
079       * Returns the plugin type.
080       *
081       * @return the plugin type
082       */
083      public final Class<P> getType() {
084        return type;
085      }
086    
087      /**
088       * Returns a list of {@link PropertyDescriptor} this plugin requires for its configuration.
089       *
090       * @return the configuration capabilities
091       */
092      protected Iterable<PropertyDescriptor<?>> createConfigurationCapabilities() {
093        return Collections.emptyList();
094      }
095    
096      /**
097       * Returns a list of {@link PropertyDescriptor} this plugin requires for its configuration.
098       *
099       * @return the configuration capabilities
100       */
101      public final Iterable<PropertyDescriptor<?>> getConfigurationCapabilities() {
102        if (configurationCapabilities == null) {
103          List<PropertyDescriptor<?>> configurationCapabilities = Collections.emptyList();
104          for (PropertyDescriptor<?> pd : createConfigurationCapabilities()) {
105            if (configurationCapabilities.isEmpty()) {
106              configurationCapabilities = new ArrayList<PropertyDescriptor<?>>();
107            }
108            configurationCapabilities.add(pd);
109          }
110          this.configurationCapabilities = configurationCapabilities.isEmpty() ? configurationCapabilities : Collections.unmodifiableList(configurationCapabilities);
111        }
112        return configurationCapabilities;
113      }
114    
115      /**
116       * Returns the implementation.
117       *
118       * @return the implementation
119       */
120      public abstract P getImplementation();
121    
122      /**
123       * Implement this method to know about init life cycle callback.
124       */
125      public void init() {
126      }
127    
128      /**
129       * Implement this method to know about destroy life cycle callback.
130       */
131      public void destroy() {
132      }
133    
134      @Override
135      public String toString() {
136        return "Plugin[type=" + getClass().getSimpleName() + ",interface=" + type.getSimpleName() + "]";
137      }
138    }