libjava/java/io/FilterWriter.java

   1 /* FilterWriter.java -- Parent class for output streams that filter
   2    Copyright (C) 1998, 1999, 2001, 2003, 2005  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.io;
  40
  41 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
  42  * "The Java Language Specification", ISBN 0-201-63451-1
  43  * Status:  Complete to version 1.1.
  44  */
  45
  46 /**
  47   * This class is the common superclass of output character stream classes
  48   * that filter the output they write.  These classes typically transform the
  49   * data in some way prior to writing it out to another underlying
  50   * <code>Writer</code>.  This class simply overrides all the
  51   * methods in <code>Writer</code> to redirect them to the
  52   * underlying stream.  Subclasses provide actual filtering.
  53   *
  54   * @author Aaron M. Renn (arenn@urbanophile.com)
  55   * @author Tom Tromey (tromey@cygnus.com)
  56   */
  57 public abstract class FilterWriter extends Writer
  58 {
  59   /**
  60     * This is the subordinate <code>Writer</code> that this class
  61     * redirects its method calls to.
  62     */
  63   protected Writer out;
  64
  65   /**
  66     * This method initializes an instance of <code>FilterWriter</code>
  67     * to write to the specified subordinate <code>Writer</code>.
  68     * The given <code>Writer</code> will be used as <code>lock</code> for
  69     * the newly created <code>FilterWriter</code>.
  70     *
  71     * @param out The <code>Writer</code> to write to
  72     */
  73   protected FilterWriter(Writer out)
  74   {
  75     super(out.lock);
  76     this.out = out;
  77   }
  78
  79   /**
  80     * This method closes the underlying <code>Writer</code>.  Any
  81     * further attempts to write to this stream may throw an exception.
  82     *
  83     * @exception IOException If an error occurs
  84     */
  85   public void close() throws IOException
  86   {
  87     out.close();
  88   }
  89
  90   /**
  91     * This method attempt to flush all buffered output to be written to the
  92     * underlying output sink.
  93     *
  94     * @exception IOException If an error occurs
  95     */
  96   public void flush() throws IOException
  97   {
  98     out.flush();
  99   }
 100
 101   /**
 102     * This method writes a single char of output to the underlying
 103     * <code>Writer</code>.
 104     *
 105     * @param b The char to write, passed as an int.
 106     *
 107     * @exception IOException If an error occurs
 108     */
 109   public void write(int b) throws IOException
 110   {
 111     out.write(b);
 112   }
 113
 114   /**
 115     * This method writes <code>len</code> chars from the array <code>buf</code>
 116     * starting at index <code>offset</code> to the underlying
 117     * <code>Writer</code>.
 118     *
 119     * @param buf The char array to write chars from
 120     * @param offset The index into the array to start writing chars from
 121     * @param len The number of chars to write
 122     *
 123     * @exception IOException If an error occurs
 124     */
 125   public void write(char[] buf, int offset, int len) throws IOException
 126   {
 127     out.write(buf, offset, len);
 128   }
 129
 130   /**
 131     * This method writes <code>len</code> chars from the <code>String</code>
 132     * starting at position <code>offset</code>.
 133     *
 134     * @param str The <code>String</code> that is to be written
 135     * @param offset The character offset into the <code>String</code>
 136     * to start writing from
 137     * @param len The number of chars to write
 138     *
 139     * @exception IOException If an error occurs
 140     */
 141   public void write(String str, int offset, int len) throws IOException
 142   {
 143     out.write(str, offset, len);
 144   }
 145
 146 } // class FilterWriter
 147