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.util;
021    
022    import org.slf4j.Logger;
023    import org.slf4j.LoggerFactory;
024    
025    import java.io.Closeable;
026    import java.util.ArrayList;
027    import java.util.concurrent.atomic.AtomicBoolean;
028    
029    public final class CloseableList implements Closeable {
030    
031      /** . */
032      final Logger log = LoggerFactory.getLogger(CloseableList.class);
033    
034      /** . */
035      private final ArrayList<Closeable> closeables;
036    
037      /** . */
038      private final AtomicBoolean closed;
039    
040      public CloseableList() {
041        this.closeables = new ArrayList<Closeable>();
042        this.closed = new AtomicBoolean(false);
043      }
044    
045      public boolean isClosed() {
046        return closed.get();
047      }
048    
049      /**
050       * Add a closeable to the list.
051       *
052       * @param closeable the closeable to add
053       * @throws IllegalStateException if the list is already closed
054       * @throws NullPointerException if the argument is null
055       */
056      public void add(Closeable closeable) throws IllegalStateException, NullPointerException {
057        if (closed.get()) {
058          throw new IllegalStateException("Already closed");
059        }
060        if (closeable == null) {
061          throw new NullPointerException("No null closeable accepted");
062        }
063        if (!closeables.contains(closeable)) {
064          closeables.add(closeable);
065        }
066      }
067    
068      public void close() {
069        if (closed.compareAndSet(false, true)) {
070          for (Closeable closeable : closeables) {
071            log.debug("Closing " + closeable.getClass().getSimpleName());
072            Safe.close(closeable);
073          }
074        }
075      }
076    }