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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/java/nio/channels/spi/AbstractSelectableChannel.java | |
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Diffstat (limited to 'libjava/classpath/java/nio/channels/spi/AbstractSelectableChannel.java')
-rw-r--r-- | libjava/classpath/java/nio/channels/spi/AbstractSelectableChannel.java | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/libjava/classpath/java/nio/channels/spi/AbstractSelectableChannel.java b/libjava/classpath/java/nio/channels/spi/AbstractSelectableChannel.java new file mode 100644 index 000000000..97ed685b8 --- /dev/null +++ b/libjava/classpath/java/nio/channels/spi/AbstractSelectableChannel.java @@ -0,0 +1,271 @@ +/* AbstractSelectableChannel.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.ClosedChannelException; +import java.nio.channels.SelectableChannel; +import java.nio.channels.SelectionKey; +import java.nio.channels.Selector; +import java.nio.channels.IllegalBlockingModeException; +import java.util.Iterator; +import java.util.LinkedList; +import java.util.ListIterator; + +public abstract class AbstractSelectableChannel extends SelectableChannel +{ + private boolean blocking = true; + private Object LOCK = new Object(); + private SelectorProvider provider; + private LinkedList keys = new LinkedList(); + + /** + * Initializes the channel + * + * @param provider the provider that created this channel + */ + protected AbstractSelectableChannel(SelectorProvider provider) + { + this.provider = provider; + } + + /** + * Retrieves the object upon which the configureBlocking and register + * methods synchronize. + * + * @return the blocking lock + */ + public final Object blockingLock() + { + return LOCK; + } + + /** + * Adjusts this channel's blocking mode. + * + * @param blocking true if blocking should be enabled, false otherwise + * + * @return this channel + * + * @exception IOException If an error occurs + */ + public final SelectableChannel configureBlocking(boolean blocking) + throws IOException + { + synchronized (blockingLock()) + { + if (this.blocking != blocking) + { + implConfigureBlocking(blocking); + this.blocking = blocking; + } + } + + return this; + } + + /** + * Closes this channel. + * + * @exception IOException If an error occurs + */ + protected final void implCloseChannel() throws IOException + { + try + { + implCloseSelectableChannel(); + } + finally + { + for (Iterator it = keys.iterator(); it.hasNext(); ) + ((SelectionKey) it.next()).cancel(); + } + } + + /** + * Closes this selectable channel. + * + * @exception IOException If an error occurs + */ + protected abstract void implCloseSelectableChannel() + throws IOException; + + /** + * Adjusts this channel's blocking mode. + * + * @param blocking true if blocking should be enabled, false otherwise + * + * @exception IOException If an error occurs + */ + protected abstract void implConfigureBlocking(boolean blocking) + throws IOException; + + /** + * Tells whether or not every I/O operation on this channel will block + * until it completes. + * + * @return true of this channel is blocking, false otherwise + */ + public final boolean isBlocking() + { + return blocking; + } + + /** + * Tells whether or not this channel is currently registered with + * any selectors. + * + * @return true if this channel is registered, false otherwise + */ + public final boolean isRegistered() + { + return ! keys.isEmpty(); + } + + /** + * Retrieves the key representing the channel's registration with the + * given selector. + * + * @param selector the selector to get a selection key for + * + * @return the selection key this channel is registered with + */ + public final SelectionKey keyFor(Selector selector) + { + if (! isOpen()) + return null; + + try + { + synchronized (blockingLock()) + { + return locate(selector); + } + } + catch (Exception e) + { + return null; + } + } + + /** + * Returns the provider that created this channel. + * + * @return the selector provider that created this channel + */ + public final SelectorProvider provider() + { + return provider; + } + + private SelectionKey locate(Selector selector) + { + ListIterator it = keys.listIterator(); + + while (it.hasNext()) + { + SelectionKey key = (SelectionKey) it.next(); + + if (key.selector() == selector) + return key; + } + + return null; + } + + /** + * Registers this channel with the given selector, returning a selection key. + * + * @param selin the seletor to use + * @param ops the interested operations + * @param att an attachment for the returned selection key + * + * @return the registered selection key + * + * @exception ClosedChannelException If the channel is already closed. + * @exception IllegalBlockingModeException If the channel is configured in + * blocking mode. + */ + public final SelectionKey register(Selector selin, int ops, Object att) + throws ClosedChannelException + { + if (! isOpen()) + throw new ClosedChannelException(); + + if ((ops & ~validOps()) != 0) + throw new IllegalArgumentException(); + + SelectionKey key = null; + AbstractSelector selector = (AbstractSelector) selin; + + synchronized (blockingLock()) + { + if (blocking) + throw new IllegalBlockingModeException(); + + key = locate(selector); + + if (key != null && key.isValid()) + { + key.interestOps(ops); + key.attach(att); + } + else + { + key = selector.register(this, ops, att); + + if (key != null) + addSelectionKey(key); + } + } + + return key; + } + + void addSelectionKey(SelectionKey key) + { + keys.add(key); + } + + // This method gets called by AbstractSelector.deregister(). + void removeSelectionKey(SelectionKey key) + { + keys.remove(key); + } +} |