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/*
* Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.nio.ch;
import java.nio.channels.spi.AsynchronousChannelProvider;
import java.nio.channels.*;
import java.io.IOException;
import java.io.Closeable;
import java.io.FileDescriptor;
import java.util.Map;
import java.util.HashMap;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
* Base implementation of AsynchronousChannelGroupImpl for Unix systems.
*/
abstract class Port extends AsynchronousChannelGroupImpl {
/**
* Implemented by clients registered with this port.
*/
interface PollableChannel extends Closeable {
void onEvent(int events, boolean mayInvokeDirect);
}
// maps fd to "pollable" channel
protected final ReadWriteLock fdToChannelLock = new ReentrantReadWriteLock();
protected final Map<Integer,PollableChannel> fdToChannel =
new HashMap<Integer,PollableChannel>();
Port(AsynchronousChannelProvider provider, ThreadPool pool) {
super(provider, pool);
}
/**
* Register channel identified by its file descriptor
*/
final void register(int fd, PollableChannel ch) {
fdToChannelLock.writeLock().lock();
try {
if (isShutdown())
throw new ShutdownChannelGroupException();
fdToChannel.put(Integer.valueOf(fd), ch);
} finally {
fdToChannelLock.writeLock().unlock();
}
}
/**
* Callback method for implementations that need special handling when fd is
* removed (currently only needed in the AIX-Port - see AixPollPort.java).
*/
protected void preUnregister(int fd) {
// Do nothing by default.
}
/**
* Unregister channel identified by its file descriptor
*/
final void unregister(int fd) {
boolean checkForShutdown = false;
preUnregister(fd);
fdToChannelLock.writeLock().lock();
try {
fdToChannel.remove(Integer.valueOf(fd));
// last key to be removed so check if group is shutdown
if (fdToChannel.isEmpty())
checkForShutdown = true;
} finally {
fdToChannelLock.writeLock().unlock();
}
// continue shutdown
if (checkForShutdown && isShutdown()) {
try {
shutdownNow();
} catch (IOException ignore) { }
}
}
/**
* Register file descriptor with polling mechanism for given events.
* The implementation should translate the events as required.
*/
abstract void startPoll(int fd, int events);
@Override
final boolean isEmpty() {
fdToChannelLock.writeLock().lock();
try {
return fdToChannel.isEmpty();
} finally {
fdToChannelLock.writeLock().unlock();
}
}
@Override
final Object attachForeignChannel(final Channel channel, FileDescriptor fd) {
int fdVal = IOUtil.fdVal(fd);
register(fdVal, new PollableChannel() {
public void onEvent(int events, boolean mayInvokeDirect) { }
public void close() throws IOException {
channel.close();
}
});
return Integer.valueOf(fdVal);
}
@Override
final void detachForeignChannel(Object key) {
unregister((Integer)key);
}
@Override
final void closeAllChannels() {
/**
* Close channels in batches of up to 128 channels. This allows close
* to remove the channel from the map without interference.
*/
final int MAX_BATCH_SIZE = 128;
PollableChannel channels[] = new PollableChannel[MAX_BATCH_SIZE];
int count;
do {
// grab a batch of up to 128 channels
fdToChannelLock.writeLock().lock();
count = 0;
try {
for (Integer fd: fdToChannel.keySet()) {
channels[count++] = fdToChannel.get(fd);
if (count >= MAX_BATCH_SIZE)
break;
}
} finally {
fdToChannelLock.writeLock().unlock();
}
// close them
for (int i=0; i<count; i++) {
try {
channels[i].close();
} catch (IOException ignore) { }
}
} while (count > 0);
}
}
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