Source for java.io.OutputStream

   1: /* OutputStream.java -- Base class for byte output streams
   2:    Copyright (C) 1998, 1999, 2001, 2004, 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: /**
  42:   * This abstract class forms the base of the hierarchy of classes that 
  43:   * write output as a stream of bytes.  It provides a common set of methods
  44:   * for writing bytes to stream.  Subclasses implement and/or extend these
  45:   * methods to write bytes in a particular manner or to a particular 
  46:   * destination such as a file on disk or network connection.
  47:   *
  48:   * @author Aaron M. Renn (arenn@urbanophile.com)
  49:   * @author Tom Tromey (tromey@cygnus.com)
  50:   */
  51: public abstract class OutputStream implements Closeable, Flushable
  52: {
  53:   /**
  54:    * This is the default no-argument constructor for this class.  This method
  55:    * does nothing in this class.
  56:    */
  57:   public OutputStream ()
  58:   {
  59:   }
  60: 
  61:   /**
  62:    * This method writes a single byte to the output stream.  The byte written
  63:    * is the low eight bits of the <code>int</code> passed and a argument.
  64:    * <p>
  65:    * Subclasses must provide an implementation of this abstract method
  66:    *
  67:    * @param b The byte to be written to the output stream, passed as
  68:    *          the low eight bits of an <code>int</code> 
  69:    *
  70:    * @exception IOException If an error occurs
  71:    */
  72:   public abstract void write (int b) throws IOException;
  73: 
  74:   /**
  75:    * This method all the writes bytes from the passed array to the
  76:    * output stream.  This method is equivalent to <code>write(b, 0,
  77:    * buf.length)</code> which is exactly how it is implemented in this
  78:    * class.
  79:    *
  80:    * @param b The array of bytes to write
  81:    *
  82:    * @exception IOException If an error occurs
  83:    */
  84:   public void write (byte[] b) throws IOException, NullPointerException
  85:   {
  86:     write (b, 0, b.length);
  87:   }
  88: 
  89:   /**
  90:    * This method writes <code>len</code> bytes from the specified array
  91:    * <code>b</code> starting at index <code>off</code> into the array.
  92:    * <p>
  93:    * This method in this class calls the single byte <code>write()</code>
  94:    * method in a loop until all bytes have been written.  Subclasses should
  95:    * override this method if possible in order to provide a more efficent
  96:    * implementation.
  97:    *
  98:    * @param b The array of bytes to write from
  99:    * @param off The index into the array to start writing from
 100:    * @param len The number of bytes to write
 101:    * 
 102:    * @exception IOException If an error occurs
 103:    */
 104:   public void write (byte[] b, int off, int len)
 105:     throws IOException, NullPointerException, IndexOutOfBoundsException
 106:   {
 107:     if (off < 0 || len < 0 || off + len > b.length)
 108:       throw new ArrayIndexOutOfBoundsException ();
 109:     for (int i = 0; i < len; ++i)
 110:       write (b[off + i]);
 111:   }
 112: 
 113:   /**
 114:    * This method forces any data that may have been buffered to be written
 115:    * to the underlying output device.  Please note that the host environment
 116:    * might perform its own buffering unbeknowst to Java.  In that case, a
 117:    * write made (for example, to a disk drive) might be cached in OS
 118:    * buffers instead of actually being written to disk.
 119:    * <p>
 120:    * This method in this class does nothing.
 121:    *
 122:    * @exception IOException If an error occurs
 123:    */
 124:   public void flush () throws IOException
 125:   {
 126:   }
 127: 
 128:   /**
 129:    * This method closes the stream.  Any internal or native resources
 130:    * associated with this stream are freed.  Any subsequent attempt to
 131:    * access the stream might throw an exception.
 132:    * <p>
 133:    * This method in this class does nothing.
 134:    *
 135:    * @exception IOException If an error occurs
 136:    */
 137:   public void close () throws IOException
 138:   {
 139:   }
 140: }