/*
* Copyright 2011 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package org.jboss.netty.channel.socket.nio;
import static org.jboss.netty.channel.Channels.*;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.SocketAddress;
import java.nio.channels.DatagramChannel;
import java.util.Queue;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.AbstractChannel;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelException;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelSink;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.socket.DatagramChannelConfig;
import org.jboss.netty.channel.socket.nio.SocketSendBufferPool.SendBuffer;
import org.jboss.netty.util.internal.LinkedTransferQueue;
import org.jboss.netty.util.internal.ThreadLocalBoolean;
/**
* Provides an NIO based {@link org.jboss.netty.channel.socket.DatagramChannel}.
*/
class NioDatagramChannel extends AbstractChannel
implements org.jboss.netty.channel.socket.DatagramChannel {
/**
* The {@link DatagramChannelConfig}.
*/
private final NioDatagramChannelConfig config;
/**
* The {@link NioDatagramWorker} for this NioDatagramChannnel.
*/
final NioDatagramWorker worker;
/**
* The {@link DatagramChannel} that this channel uses.
*/
private final java.nio.channels.DatagramChannel datagramChannel;
/**
* Monitor object to synchronize access to InterestedOps.
*/
final Object interestOpsLock = new Object();
/**
* Monitor object for synchronizing access to the {@link WriteRequestQueue}.
*/
final Object writeLock = new Object();
/**
* WriteTask that performs write operations.
*/
final Runnable writeTask = new WriteTask();
/**
* Indicates if there is a {@link WriteTask} in the task queue.
*/
final AtomicBoolean writeTaskInTaskQueue = new AtomicBoolean();
/**
* Queue of write {@link MessageEvent}s.
*/
final Queue<MessageEvent> writeBufferQueue = new WriteRequestQueue();
/**
* Keeps track of the number of bytes that the {@link WriteRequestQueue} currently
* contains.
*/
final AtomicInteger writeBufferSize = new AtomicInteger();
/**
* Keeps track of the highWaterMark.
*/
final AtomicInteger highWaterMarkCounter = new AtomicInteger();
/**
* The current write {@link MessageEvent}
*/
MessageEvent currentWriteEvent;
SendBuffer currentWriteBuffer;
/**
* Boolean that indicates that write operation is in progress.
*/
boolean inWriteNowLoop;
boolean writeSuspended;
private volatile InetSocketAddress localAddress;
volatile InetSocketAddress remoteAddress;
NioDatagramChannel(final ChannelFactory factory,
final ChannelPipeline pipeline, final ChannelSink sink,
final NioDatagramWorker worker) {
super(null, factory, pipeline, sink);
this.worker = worker;
datagramChannel = openNonBlockingChannel();
config = new DefaultNioDatagramChannelConfig(datagramChannel.socket());
fireChannelOpen(this);
}
private DatagramChannel openNonBlockingChannel() {
try {
final DatagramChannel channel = DatagramChannel.open();
channel.configureBlocking(false);
return channel;
} catch (final IOException e) {
throw new ChannelException("Failed to open a DatagramChannel.", e);
}
}
public InetSocketAddress getLocalAddress() {
InetSocketAddress localAddress = this.localAddress;
if (localAddress == null) {
try {
this.localAddress = localAddress =
(InetSocketAddress) datagramChannel.socket().getLocalSocketAddress();
} catch (Throwable t) {
// Sometimes fails on a closed socket in Windows.
return null;
}
}
return localAddress;
}
public InetSocketAddress getRemoteAddress() {
InetSocketAddress remoteAddress = this.remoteAddress;
if (remoteAddress == null) {
try {
this.remoteAddress = remoteAddress =
(InetSocketAddress) datagramChannel.socket().getRemoteSocketAddress();
} catch (Throwable t) {
// Sometimes fails on a closed socket in Windows.
return null;
}
}
return remoteAddress;
}
public boolean isBound() {
return isOpen() && datagramChannel.socket().isBound();
}
public boolean isConnected() {
return datagramChannel.isConnected();
}
@Override
protected boolean setClosed() {
return super.setClosed();
}
public NioDatagramChannelConfig getConfig() {
return config;
}
DatagramChannel getDatagramChannel() {
return datagramChannel;
}
@Override
public int getInterestOps() {
if (!isOpen()) {
return Channel.OP_WRITE;
}
int interestOps = getRawInterestOps();
int writeBufferSize = this.writeBufferSize.get();
if (writeBufferSize != 0) {
if (highWaterMarkCounter.get() > 0) {
int lowWaterMark = getConfig().getWriteBufferLowWaterMark();
if (writeBufferSize >= lowWaterMark) {
interestOps |= Channel.OP_WRITE;
} else {
interestOps &= ~Channel.OP_WRITE;
}
} else {
int highWaterMark = getConfig().getWriteBufferHighWaterMark();
if (writeBufferSize >= highWaterMark) {
interestOps |= Channel.OP_WRITE;
} else {
interestOps &= ~Channel.OP_WRITE;
}
}
} else {
interestOps &= ~Channel.OP_WRITE;
}
return interestOps;
}
int getRawInterestOps() {
return super.getInterestOps();
}
void setRawInterestOpsNow(int interestOps) {
super.setInterestOpsNow(interestOps);
}
@Override
public ChannelFuture write(Object message, SocketAddress remoteAddress) {
if (remoteAddress == null || remoteAddress.equals(getRemoteAddress())) {
return super.write(message, null);
} else {
return super.write(message, remoteAddress);
}
}
/**
* {@link WriteRequestQueue} is an extension of {@link LinkedTransferQueue}
* that adds support for highWaterMark checking of the write buffer size.
*/
private final class WriteRequestQueue extends
AbstractWriteRequestQueue {
private final ThreadLocalBoolean notifying = new ThreadLocalBoolean();
WriteRequestQueue() {
super();
}
/**
* This method first delegates to {@link LinkedTransferQueue#offer(Object)} and
* adds support for keeping track of the size of the this write buffer.
*/
public boolean offer(MessageEvent e) {
boolean success = queue.offer(e);
assert success;
int messageSize = getMessageSize(e);
int newWriteBufferSize = writeBufferSize.addAndGet(messageSize);
int highWaterMark = getConfig().getWriteBufferHighWaterMark();
if (newWriteBufferSize >= highWaterMark) {
if (newWriteBufferSize - messageSize < highWaterMark) {
highWaterMarkCounter.incrementAndGet();
if (!notifying.get()) {
notifying.set(Boolean.TRUE);
fireChannelInterestChanged(NioDatagramChannel.this);
notifying.set(Boolean.FALSE);
}
}
}
return true;
}
/**
* This method first delegates to {@link LinkedTransferQueue#poll()} and
* adds support for keeping track of the size of the this writebuffers queue.
*/
public MessageEvent poll() {
MessageEvent e = queue.poll();
if (e != null) {
int messageSize = getMessageSize(e);
int newWriteBufferSize = writeBufferSize.addAndGet(-messageSize);
int lowWaterMark = getConfig().getWriteBufferLowWaterMark();
if (newWriteBufferSize == 0 || newWriteBufferSize < lowWaterMark) {
if (newWriteBufferSize + messageSize >= lowWaterMark) {
highWaterMarkCounter.decrementAndGet();
if (isBound() && !notifying.get()) {
notifying.set(Boolean.TRUE);
fireChannelInterestChanged(NioDatagramChannel.this);
notifying.set(Boolean.FALSE);
}
}
}
}
return e;
}
private int getMessageSize(MessageEvent e) {
Object m = e.getMessage();
if (m instanceof ChannelBuffer) {
return ((ChannelBuffer) m).readableBytes();
}
return 0;
}
}
/**
* WriteTask is a simple runnable performs writes by delegating the {@link NioDatagramWorker}.
*/
private final class WriteTask implements Runnable {
WriteTask() {
super();
}
public void run() {
writeTaskInTaskQueue.set(false);
worker.writeFromTaskLoop(NioDatagramChannel.this);
}
}
public void joinGroup(InetAddress multicastAddress) {
throw new UnsupportedOperationException();
}
public void joinGroup(InetSocketAddress multicastAddress,
NetworkInterface networkInterface) {
throw new UnsupportedOperationException();
}
public void leaveGroup(InetAddress multicastAddress) {
throw new UnsupportedOperationException();
}
public void leaveGroup(InetSocketAddress multicastAddress,
NetworkInterface networkInterface) {
throw new UnsupportedOperationException();
}
}