content: /*
   *
   * 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.apache.bookkeeper.bookie;
  
  import java.io.File;
  import java.io.FileDescriptor;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.RandomAccessFile;
  import java.nio.channels.FileChannel;
  import org.apache.bookkeeper.conf.ServerConfiguration;
  
  /**
   * Default FileChannel for bookie to read and write.
   *
   */
  public class DefaultFileChannel implements BookieFileChannel {
      private final File file;
      private RandomAccessFile randomAccessFile;
      private final ServerConfiguration configuration;
  
      DefaultFileChannel(File file, ServerConfiguration serverConfiguration) throws IOException {
          this.file = file;
          this.configuration = serverConfiguration;
      }
  
      @Override
      public FileChannel getFileChannel() throws FileNotFoundException {
          synchronized (this) {
              if (randomAccessFile == null) {
                  randomAccessFile = new RandomAccessFile(file, "rw");
              }
              return randomAccessFile.getChannel();
          }
      }
  
      @Override
      public boolean fileExists(File file) {
          return file.exists();
      }
  
      @Override
      public FileDescriptor getFD() throws IOException {
          synchronized (this) {
              if (randomAccessFile == null) {
                  throw new IOException("randomAccessFile is null, please initialize it by calling getFileChannel");
              }
              return randomAccessFile.getFD();
          }
      }
  
      @Override
      public void close() throws IOException {
          synchronized (this) {
              if (randomAccessFile != null) {
                  randomAccessFile.close();
              }
          }
      }
  }
  