Source for java.io.FilterOutputStream

   1: /* FilterOutputStream.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., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 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 stream classes that 
  48:   * 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>OutputStream</code>.  This class simply overrides all the 
  51:   * methods in <code>OutputStream</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 class FilterOutputStream extends OutputStream
  58: {
  59:   /**
  60:     * This is the subordinate <code>OutputStream</code> that this class
  61:     * redirects its method calls to.
  62:     */
  63:   protected OutputStream out;
  64: 
  65:   /**
  66:     * This method initializes an instance of <code>FilterOutputStream</code>
  67:     * to write to the specified subordinate <code>OutputStream</code>.
  68:     *
  69:     * @param out The <code>OutputStream</code> to write to
  70:     */
  71:   public FilterOutputStream(OutputStream out)
  72:   {
  73:     this.out = out;
  74:   }
  75: 
  76:   /**
  77:     * This method closes the underlying <code>OutputStream</code>.  Any
  78:     * further attempts to write to this stream may throw an exception.
  79:     *
  80:     * @exception IOException If an error occurs
  81:     */
  82:   public void close() throws IOException
  83:   {
  84:     flush();
  85:     out.close();
  86:   }
  87: 
  88:   /**
  89:     * This method attempt to flush all buffered output to be written to the
  90:     * underlying output sink.
  91:     *
  92:     * @exception IOException If an error occurs
  93:     */
  94:   public void flush() throws IOException
  95:   {
  96:     out.flush();
  97:   }
  98: 
  99:   /**
 100:     * This method writes a single byte of output to the underlying
 101:     * <code>OutputStream</code>.
 102:     *
 103:     * @param b The byte to write, passed as an int.
 104:     *
 105:     * @exception IOException If an error occurs
 106:     */
 107:   public void write(int b) throws IOException
 108:   {
 109:     out.write(b);
 110:   }
 111: 
 112:   /**
 113:     * This method writes all the bytes in the specified array to the underlying
 114:     * <code>OutputStream</code>.  It does this by calling the three parameter
 115:     * version of this method - <code>write(byte[], int, int)</code> in this
 116:     * class instead of writing to the underlying <code>OutputStream</code>
 117:     * directly.  This allows most subclasses to avoid overriding this method.
 118:     *
 119:     * @param buf The byte array to write bytes from
 120:     *
 121:     * @exception IOException If an error occurs
 122:     */
 123:   public void write(byte[] buf) throws IOException
 124:   {
 125:     // Don't do checking here, per Java Lang Spec.
 126:     write(buf, 0, buf.length);
 127:   }
 128: 
 129:   /**
 130:     * This method calls the <code>write(int)</code> method <code>len</code>
 131:     * times for all bytes from the array <code>buf</code> starting at index
 132:     * <code>offset</code>. Subclasses should overwrite this method to get a
 133:     * more efficient implementation.
 134:     *
 135:     * @param buf The byte array to write bytes from
 136:     * @param offset The index into the array to start writing bytes from
 137:     * @param len The number of bytes to write
 138:     *
 139:     * @exception IOException If an error occurs
 140:     */
 141:   public void write(byte[] buf, int offset, int len) throws IOException
 142:   {
 143:     // Don't do checking here, per Java Lang Spec.
 144:     for (int i=0; i < len; i++) 
 145:       write(buf[offset + i]);
 146: 
 147:   }
 148: 
 149: } // class FilterOutputStream