/* FilterWriter.java -- Parent class for output streams that filter
   Copyright (C) 1998, 1999, 2001 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
 
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

As a special exception, if you link this library with other files to
produce an executable, this library does not by itself cause the
resulting executable to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why the
executable file might be covered by the GNU General Public License. */


package java.io;

/* 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.
 */

/**
  * This class is the common superclass of output character stream classes 
  * that filter the output they write.  These classes typically transform the
  * data in some way prior to writing it out to another underlying
  * <code>Writer</code>.  This class simply overrides all the 
  * methods in <code>Writer</code> to redirect them to the
  * underlying stream.  Subclasses provide actual filtering.
  *
  * @author Aaron M. Renn (arenn@urbanophile.com)
  * @author Tom Tromey <tromey@cygnus.com>
  */
public abstract class FilterWriter extends Writer
{

/*************************************************************************/

/*
 * Instance Variables
 */

/**
  * This is the subordinate <code>Writer</code> that this class
  * redirects its method calls to.
  */
protected Writer out;

/*************************************************************************/

/*
 * Constructors
 */

/**
  * This method initializes an instance of <code>FilterWriter</code>
  * to write to the specified subordinate <code>Writer</code>.
  * The given <code>Writer</code> will be used as <code>lock</code> for
  * the newly created <code>FilterWriter</code>.
  *
  * @param out The <code>Writer</code> to write to
  */
protected
FilterWriter(Writer out)
{
  super(out);
  this.out = out;
}

/*************************************************************************/

/*
 * Instance Methods
 */

/**
  * This method closes the underlying <code>Writer</code>.  Any
  * further attempts to write to this stream may throw an exception.
  *
  * @exception IOException If an error occurs
  */
public void
close() throws IOException
{
  out.close();
}

/*************************************************************************/

/**
  * This method attempt to flush all buffered output to be written to the
  * underlying output sink.
  *
  * @exception IOException If an error occurs
  */
public void
flush() throws IOException
{
  out.flush();
}

/*************************************************************************/

/**
  * This method writes a single char of output to the underlying
  * <code>Writer</code>.
  *
  * @param b The char to write, passed as an int.
  *
  * @exception IOException If an error occurs
  */
public void
write(int b) throws IOException
{
  out.write(b);
}

/*************************************************************************/

/**
  * This method writes <code>len</code> chars from the array <code>buf</code>
  * starting at index <code>offset</code> to the underlying
  * <code>Writer</code>.
  *
  * @param buf The char array to write chars from
  * @param offset The index into the array to start writing chars from
  * @param len The number of chars to write
  *
  * @exception IOException If an error occurs
  */
public void
write(char[] buf, int offset, int len) throws IOException
{
  out.write(buf, offset, len);
}

/*************************************************************************/

/**
  * This method writes <code>len</code> chars from the <code>String</code>
  * starting at position <code>offset</code>.
  *
  * @param str The <code>String</code> that is to be written
  * @param offset The character offset into the <code>String</code> to start writing from
  * @param len The number of chars to write
  *
  * @exception IOException If an error occurs
  */
public void
write(String str, int offset, int len) throws IOException
{
  out.write(str, offset, len);
}

} // class FilterWriter