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