/* $HeadURL::                                                                            $
    * $Id$
    *
    * Copyright (c) 2009-2010 DuraSpace
    * http://duraspace.org
    *
    * In collaboration with Topaz Inc.
    * http://www.topazproject.org
    *
   * Licensed 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.akubraproject.fs;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  
  import java.net.URI;
  
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Set;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.akubraproject.Blob;
  import org.akubraproject.BlobStore;
  import org.akubraproject.impl.AbstractBlobStoreConnection;
  import org.akubraproject.impl.StreamManager;
  
  /**
   * Filesystem-backed BlobStoreConnection implementation.
   *
   * @author Chris Wilper
   */
  class FSBlobStoreConnection extends AbstractBlobStoreConnection {
    private static final Logger log = LoggerFactory.getLogger(FSBlobStoreConnection.class);
  
    private final File baseDir;
    private final Set<File>     modified;
  
    FSBlobStoreConnection(BlobStore blobStore, File baseDir, StreamManager manager, boolean noSync) {
      super(blobStore, manager);
      this.baseDir = baseDir;
      this.modified = noSync ? null : new HashSet<File>();
    }
  
    @Override
    public Blob getBlob(URI blobId, Map<String, String> hints) throws IOException {
      ensureOpen();
  
      if (blobId == null)
        throw new UnsupportedOperationException();
  
      return new FSBlob(this, baseDir, blobId, streamManager, modified);
    }
  
    @Override
    public Iterator<URI> listBlobIds(String filterPrefix) {
      ensureOpen();
      return new FSBlobIdIterator(baseDir, filterPrefix);
    }
  
    @Override
    public void sync() throws IOException {
      ensureOpen();
  
      if (modified == null)
        throw new UnsupportedOperationException("You promised you weren't going to call sync!");
  
      for (File f : modified) {
        try {
          FileInputStream fis = new FileInputStream(f);
          try {
            fis.getFD().sync();
          } finally {
            fis.close();
          }
        } catch (IOException ioe) {
          log.warn("Error sync'ing file '" + f + "'", ioe);
        }
      }
  
      modified.clear();
    }
  
    @Override
   public void close() {
     if (modified != null)
       modified.clear();
 
     super.close();
   }
 }