Source for java.nio.channels.Selector

   1: /* Selector.java --
   2:    Copyright (C) 2002 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;
  39: 
  40: import java.io.IOException;
  41: import java.nio.channels.spi.SelectorProvider;
  42: import java.util.Set;
  43: 
  44: 
  45: /**
  46:  * @author Michael Koch
  47:  * @since 1.4
  48:  */
  49: public abstract class Selector
  50: {
  51:   /**
  52:    * Initializes the selector.
  53:    */
  54:   protected Selector()
  55:   {
  56:   }
  57: 
  58:   /**
  59:    * Opens a selector.
  60:    *
  61:    * @exception IOException If an error occurs
  62:    */
  63:   public static Selector open() throws IOException
  64:   {
  65:     return SelectorProvider.provider().openSelector();
  66:   }
  67: 
  68:   /**
  69:    * Closes the selector.
  70:    *
  71:    * @exception IOException If an error occurs
  72:    */
  73:   public abstract void close() throws IOException;
  74: 
  75:   /**
  76:    * Tells whether the selector is open or not.
  77:    */
  78:   public abstract boolean isOpen();
  79: 
  80:   /**
  81:    * Returns this selector's key set.
  82:    *
  83:    * @exception ClosedSelectorException If this selector is closed.
  84:    */
  85:   public abstract Set<SelectionKey> keys();
  86: 
  87:   /**
  88:    * Returns the SelectorProvider that created the selector.
  89:    */
  90:   public abstract SelectorProvider provider();
  91: 
  92:   /**
  93:    * Selects a set of keys whose corresponding channels are ready
  94:    * for I/O operations.
  95:    *
  96:    * @exception ClosedSelectorException If this selector is closed.
  97:    * @exception IOException If an error occurs
  98:    */
  99:   public abstract int select() throws IOException;
 100: 
 101:   /**
 102:    * Selects a set of keys whose corresponding channels are ready
 103:    * for I/O operations.
 104:    *
 105:    * @param timeout The timeout to use.
 106:    *
 107:    * @exception ClosedSelectorException If this selector is closed.
 108:    * @exception IllegalArgumentException If the timeout value is negative.
 109:    * @exception IOException If an error occurs
 110:    */
 111:   public abstract int select(long timeout) throws IOException;
 112: 
 113:   /**
 114:    * Returns this selector's selected-key set.
 115:    *
 116:    * @exception ClosedSelectorException If this selector is closed.
 117:    */
 118:   public abstract Set<SelectionKey> selectedKeys();
 119: 
 120:   /**
 121:    * Selects a set of keys whose corresponding channels are ready
 122:    * for I/O operations.
 123:    *
 124:    * @exception ClosedSelectorException If this selector is closed.
 125:    * @exception IOException If an error occurs
 126:    */
 127:   public abstract int selectNow() throws IOException;
 128: 
 129:   /**
 130:    * Causes the first selection operation that has not yet returned to
 131:    * return immediately.
 132:    */
 133:   public abstract Selector wakeup();
 134: }