Source for java.nio.channels.spi.AbstractSelectionKey

   1: /* AbstractSelectionKey.java --
   2:    Copyright (C) 2002, 2003, 2004, 2006  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.nio.channels.SelectionKey;
  41: 
  42: 
  43: /**
  44:  * @since 1.4
  45:  */
  46: public abstract class AbstractSelectionKey extends SelectionKey
  47: {
  48:   private boolean cancelled;
  49: 
  50:   /**
  51:    * Initializes the key.
  52:    */
  53:   protected AbstractSelectionKey()
  54:   {
  55:   }
  56: 
  57:   /**
  58:    * Cancels this key.
  59:    */
  60:   public final synchronized void cancel()
  61:   {
  62:     if (isValid())
  63:       {
  64:         ((AbstractSelector) selector()).cancelKey(this);
  65:         cancelled = true;
  66:       }
  67:   }
  68: 
  69:   /**
  70:    * Tells whether this key is valid or not.
  71:    *
  72:    * @return true if this key is valid, false otherwise
  73:    */
  74:   public final synchronized boolean isValid()
  75:   {
  76:     return ! cancelled;
  77:   }
  78: }