seekablefileoutputstream.java

JAVA网络编程技术内幕一书的源代码

/*
 * Java Network Programming, Second Edition
 * Merlin Hughes, Michael Shoffner, Derek Hamner
 * Manning Publications Company; ISBN 188477749X
 *
 * http://nitric.com/jnp/
 *
 * Copyright (c) 1997-1999 Merlin Hughes, Michael Shoffner, Derek Hamner;
 * all rights reserved; see license.txt for details.
 */

import java.io.*;

public class SeekableFileOutputStream extends FileOutputStream {
  public SeekableFileOutputStream (String filename) throws IOException {
    this (new RandomAccessFile (filename, "rw"));
  }

  public SeekableFileOutputStream (File file) throws IOException {
    this (file.getPath ());
  }

  protected RandomAccessFile file;

  protected SeekableFileOutputStream (RandomAccessFile file) throws IOException {
    super (file.getFD ());
    this.file = file;
  }

  public void setPosition (long position) throws IOException {
    file.seek (position);
  }
  
  public long getPosition () throws IOException {
    return file.getFilePointer ();
  }

  public long getLength () throws IOException {
    return file.length ();
  }
}