Source for java.nio.channels.spi.AbstractInterruptibleChannel

   1: /* AbstractInterruptibleChannel.java -- 
   2:    Copyright (C) 2002, 2004 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: package java.nio.channels.spi;
  39: 
  40: import java.io.IOException;
  41: import java.nio.channels.AsynchronousCloseException;
  42: import java.nio.channels.Channel;
  43: import java.nio.channels.ClosedByInterruptException;
  44: import java.nio.channels.InterruptibleChannel;
  45: 
  46: 
  47: /**
  48:  * @author Michael Koch
  49:  * @since 1.4
  50:  */
  51: public abstract class AbstractInterruptibleChannel
  52:   implements Channel, InterruptibleChannel
  53: {
  54:   private boolean closed;
  55: 
  56:   /**
  57:    * Initializes the channel.
  58:    */
  59:   protected AbstractInterruptibleChannel()
  60:   {
  61:   }
  62: 
  63:   /**
  64:    * Marks the beginning of an I/O operation that might block indefinitely.
  65:    */
  66:   protected final void begin()
  67:   {
  68:   }
  69: 
  70:   /**
  71:    * Closes the channel.
  72:    *
  73:    * @exception IOException If an error occurs
  74:    */
  75:   public final void close() throws IOException
  76:   {
  77:     if (! closed)
  78:       {
  79:     closed = true;
  80:     implCloseChannel();
  81:       }
  82:   }
  83: 
  84:   /**
  85:    * Marks the end of an I/O operation that might block indefinitely.
  86:    *
  87:    * @param completed true if the task completed successfully,
  88:    * false otherwise
  89:    *
  90:    * @exception AsynchronousCloseException If the channel was asynchronously
  91:    * closed.
  92:    * @exception ClosedByInterruptException If the thread blocked in the
  93:    * I/O operation was interrupted.
  94:    */
  95:   protected final void end(boolean completed)
  96:     throws AsynchronousCloseException
  97:   {
  98:     // FIXME: check more here.
  99:     
 100:     if (closed) throw new AsynchronousCloseException();
 101:   }
 102: 
 103:   /**
 104:    * Closes the channel.
 105:    *
 106:    * @exception IOException If an error occurs
 107:    */
 108:   protected abstract void implCloseChannel() throws IOException;
 109: 
 110:   /**
 111:    * Tells whether or not this channel is open.
 112:    * 
 113:    * @return true if the channel is open, false otherwise 
 114:    */
 115:   public final boolean isOpen()
 116:   {
 117:     return ! closed;
 118:   }
 119: }