libjava/java/nio/channels/Selector.java

   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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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  * @author Michael Koch
  46  * @since 1.4
  47  */
  48 public abstract class Selector
  49 {
  50   /**
  51    * Initializes the selector.
  52    */
  53   protected Selector()
  54   {
  55   }
  56
  57   /**
  58    * Opens a selector.
  59    *
  60    * @exception IOException If an error occurs
  61    */
  62   public static Selector open () throws IOException
  63   {
  64     return SelectorProvider.provider ().openSelector ();
  65   }
  66
  67   /**
  68    * Closes the selector.
  69    *
  70    * @exception IOException If an error occurs
  71    */
  72   public abstract void close () throws IOException;
  73
  74   /**
  75    * Tells whether the selector is open or not.
  76    */
  77   public abstract boolean isOpen ();
  78
  79   /**
  80    * Returns this selector's key set.
  81    *
  82    * @exception ClosedSelectorException If this selector is closed.
  83    */
  84   public abstract Set keys ();
  85
  86   /**
  87    * Returns the SelectorProvider that created the selector.
  88    */
  89   public abstract SelectorProvider provider ();
  90
  91   /**
  92    * Selects a set of keys whose corresponding channels are ready
  93    * for I/O operations.
  94    *
  95    * @exception ClosedSelectorException If this selector is closed.
  96    * @exception IOException If an error occurs
  97    */
  98   public abstract int select () throws IOException;
  99
 100   /**
 101    * Selects a set of keys whose corresponding channels are ready
 102    * for I/O operations.
 103    *
 104    * @param timeout The timeout to use.
 105    *
 106    * @exception ClosedSelectorException If this selector is closed.
 107    * @exception IllegalArgumentException If the timeout value is negative.
 108    * @exception IOException If an error occurs
 109    */
 110   public abstract int select (long timeout) throws IOException;
 111
 112   /**
 113    * Returns this selector's selected-key set.
 114    *
 115    * @exception ClosedSelectorException If this selector is closed.
 116    */
 117   public abstract Set selectedKeys ();
 118
 119   /**
 120    * Selects a set of keys whose corresponding channels are ready
 121    * for I/O operations.
 122    *
 123    * @exception ClosedSelectorException If this selector is closed.
 124    * @exception IOException If an error occurs
 125    */
 126   public abstract int selectNow () throws IOException;
 127
 128   /**
 129    * Causes the first selection operation that has not yet returned to
 130    * return immediately.
 131    */
 132   public abstract Selector wakeup ();
 133 }