libjava/java/io/BufferedWriter.java

// BufferedWriter.java - Filtered character output stream.

/* Copyright (C) 1998, 1999  Cygnus Solutions

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

package java.io;

/**
 * @author Tom Tromey <tromey@cygnus.com>
 * @date September 25, 1998 
 */

/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
 * "The Java Language Specification", ISBN 0-201-63451-1
 * Status:  Complete to version 1.1.
 */

// Why not extend FilterWriter?
public class BufferedWriter extends Writer
{
  public BufferedWriter (Writer out)
  {
    this (out, 8192);
  }

  public BufferedWriter (Writer ox, int size)
  {
    super (ox);
    out = ox;
    buffer = new char[size];
    count = 0;
  }

  public void close () throws IOException
  {
    localFlush ();
    out.close();
  }

  public void flush () throws IOException
  {
    localFlush ();
    out.flush();
  }

  public void newLine () throws IOException
  {
    write (System.getProperty("line.separator"));
  }

  public void write (int oneChar) throws IOException
  {
    synchronized (lock)
      {
	buffer[count++] = (char) oneChar;
	if (count == buffer.length)
	  localFlush ();
      }
  }

  public void write (char[] buf, int offset, int len) throws IOException
  {
    if (offset < 0 || len < 0 || offset + len > buf.length)
      throw new ArrayIndexOutOfBoundsException ();

    synchronized (lock)
      {
	// Bypass buffering if there is too much incoming data.
	if (count + len > buffer.length)
	  {
	    localFlush ();
	    out.write(buf, offset, len);
	  }
	else
	  {
	    System.arraycopy(buf, offset, buffer, count, len);
	    count += len;
	    if (count == buffer.length)
	      localFlush ();
	  }
      }
  }

  public void write (String str, int offset, int len) throws IOException
  {
    if (offset < 0 || len < 0 || offset + len < str.length())
      throw new ArrayIndexOutOfBoundsException ();

    synchronized (lock)
      {
	if (count + len > buffer.length)
	  {
	    localFlush ();
	    out.write(str, offset, len);
	  }
	else
	  {
	    str.getChars(offset, offset + len, buffer, count);
	    count += len;
	    if (count == buffer.length)
	      localFlush ();
	  }
      }
  }

  private final void localFlush () throws IOException
  {
    if (count > 0)
      {
	synchronized (lock)
	  {
	    out.write(buffer, 0, count);
	    count = 0;
	  }
      }
  }

  // The downstream writer.
  private Writer out;
  // The character buffer.
  char[] buffer;
  // Number of valid chars in buffer.
  int count;
}