查看本类的 API文档回源码主页

   /*
    *  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.mina.core.file;
  
  import java.io.IOException;
  import java.nio.channels.FileChannel;
  
  /**
   * TODO Add documentation
   * 
   * 
   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
   */
  public class DefaultFileRegion implements FileRegion {
  
      private final FileChannel channel;
  
      private final long originalPosition;
  
      private long position;
  
      private long remainingBytes;
  
      public DefaultFileRegion(FileChannel channel) throws IOException {
          this(channel, 0, channel.size());
      }
  
      public DefaultFileRegion(FileChannel channel, long position, long remainingBytes) {
          if (channel == null) {
              throw new IllegalArgumentException("channel can not be null");
          }
          
          if (position < 0) {
              throw new IllegalArgumentException("position may not be less than 0");
          }
          
          if (remainingBytes < 0) {
              throw new IllegalArgumentException("remainingBytes may not be less than 0");
          }
          
          this.channel = channel;
          this.originalPosition = position;
          this.position = position;
          this.remainingBytes = remainingBytes;
      }
  
      public long getWrittenBytes() {
          return position - originalPosition;
      }
  
      public long getRemainingBytes() {
          return remainingBytes;
      }
  
      public FileChannel getFileChannel() {
          return channel;
      }
  
      public long getPosition() {
          return position;
      }
  
      public void update(long value) {
          position += value;
          remainingBytes -= value;
      }
  
      public String getFilename() {
          return null;
      }
  
  }