| /* AbstractSelector.java -- |
| Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package java.nio.channels.spi; |
| |
| import java.io.IOException; |
| import java.nio.channels.ClosedSelectorException; |
| import java.nio.channels.SelectionKey; |
| import java.nio.channels.Selector; |
| import java.util.HashSet; |
| import java.util.Set; |
| |
| |
| public abstract class AbstractSelector extends Selector |
| { |
| private boolean closed; |
| private SelectorProvider provider; |
| private HashSet cancelledKeys; |
| |
| /** |
| * Initializes the slector. |
| * |
| * @param provider the provider that created this selector |
| */ |
| protected AbstractSelector(SelectorProvider provider) |
| { |
| this.provider = provider; |
| this.cancelledKeys = new HashSet(); |
| } |
| |
| /** |
| * Closes the channel. |
| * |
| * @exception IOException If an error occurs |
| */ |
| public final synchronized void close() throws IOException |
| { |
| if (closed) |
| return; |
| |
| implCloseSelector(); |
| closed = true; |
| } |
| |
| /** |
| * Tells whether this channel is open or not. |
| * |
| * @return true if channel is open, false otherwise. |
| */ |
| public final boolean isOpen() |
| { |
| return ! closed; |
| } |
| |
| /** |
| * Marks the beginning of an I/O operation that might block indefinitely. |
| */ |
| protected final void begin() |
| { |
| } |
| |
| /** |
| * Marks the end of an I/O operation that might block indefinitely. |
| */ |
| protected final void end() |
| { |
| } |
| |
| /** |
| * Returns the provider for this selector object. |
| * |
| * @return the SelectorProvider object that created this seletor |
| */ |
| public final SelectorProvider provider() |
| { |
| return provider; |
| } |
| |
| /** |
| * Returns the cancelled keys set. |
| * |
| * @return the cancelled keys set |
| */ |
| protected final Set cancelledKeys() |
| { |
| if (! isOpen()) |
| throw new ClosedSelectorException(); |
| |
| return cancelledKeys; |
| } |
| |
| /** |
| * Cancels a selection key. |
| */ |
| |
| // This method is only called by AbstractSelectionKey.cancel(). |
| final void cancelKey(AbstractSelectionKey key) |
| { |
| synchronized (cancelledKeys) |
| { |
| cancelledKeys.add(key); |
| } |
| } |
| |
| /** |
| * Closes the channel. |
| * |
| * @exception IOException if an error occurs |
| */ |
| protected abstract void implCloseSelector() throws IOException; |
| |
| /** |
| * Registers a channel for the selection process. |
| * |
| * @param ch the channel register |
| * @param ops the interested operations |
| * @param att an attachement to the selection key |
| * |
| * @return the registered selection key |
| */ |
| protected abstract SelectionKey register(AbstractSelectableChannel ch, |
| int ops, Object att); |
| |
| /** |
| * Deregisters the given selection key. |
| * |
| * @param key the key to deregister |
| */ |
| protected final void deregister(AbstractSelectionKey key) |
| { |
| ((AbstractSelectableChannel) key.channel()).removeSelectionKey(key); |
| } |
| } |