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/*
* Copyright 2012 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.handler.timeout;
import org.jboss.netty.bootstrap.ServerBootstrap;
import org.jboss.netty.channel.ChannelHandler;
import org.jboss.netty.channel.ChannelHandler.Sharable;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.LifeCycleAwareChannelHandler;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
import org.jboss.netty.util.ExternalResourceReleasable;
import org.jboss.netty.util.HashedWheelTimer;
import org.jboss.netty.util.Timeout;
import org.jboss.netty.util.Timer;
import org.jboss.netty.util.TimerTask;
import java.util.concurrent.TimeUnit;
import static org.jboss.netty.channel.Channels.*;
/**
* Raises a {@link ReadTimeoutException} when no data was read within a certain
* period of time.
*
*
* public class MyPipelineFactory implements {@link ChannelPipelineFactory} {
*
* private final {@link Timer} timer;
* private final {@link ChannelHandler} timeoutHandler;
*
* public MyPipelineFactory({@link Timer} timer) {
* this.timer = timer;
* this.timeoutHandler = new {@link ReadTimeoutHandler}(timer, 30), // timer must be shared.
* }
*
* public {@link ChannelPipeline} getPipeline() {
* // An example configuration that implements 30-second read timeout:
* return {@link Channels}.pipeline(
* timeoutHandler,
* new MyHandler());
* }
* }
*
* {@link ServerBootstrap} bootstrap = ...;
* {@link Timer} timer = new {@link HashedWheelTimer}();
* ...
* bootstrap.setPipelineFactory(new MyPipelineFactory(timer));
* ...
*
*
* The {@link Timer} which was specified when the {@link ReadTimeoutHandler} is
* created should be stopped manually by calling {@link #releaseExternalResources()}
* or {@link Timer#stop()} when your application shuts down.
* @see WriteTimeoutHandler
* @see IdleStateHandler
*
* @apiviz.landmark
* @apiviz.uses org.jboss.netty.util.HashedWheelTimer
* @apiviz.has org.jboss.netty.handler.timeout.TimeoutException oneway - - raises
*/
@Sharable
public class ReadTimeoutHandler extends SimpleChannelUpstreamHandler
implements LifeCycleAwareChannelHandler,
ExternalResourceReleasable {
static final ReadTimeoutException EXCEPTION = new ReadTimeoutException();
final Timer timer;
final long timeoutMillis;
/**
* Creates a new instance.
*
* @param timer
* the {@link Timer} that is used to trigger the scheduled event.
* The recommended {@link Timer} implementation is {@link HashedWheelTimer}.
* @param timeoutSeconds
* read timeout in seconds
*/
public ReadTimeoutHandler(Timer timer, int timeoutSeconds) {
this(timer, timeoutSeconds, TimeUnit.SECONDS);
}
/**
* Creates a new instance.
*
* @param timer
* the {@link Timer} that is used to trigger the scheduled event.
* The recommended {@link Timer} implementation is {@link HashedWheelTimer}.
* @param timeout
* read timeout
* @param unit
* the {@link TimeUnit} of {@code timeout}
*/
public ReadTimeoutHandler(Timer timer, long timeout, TimeUnit unit) {
if (timer == null) {
throw new NullPointerException("timer");
}
if (unit == null) {
throw new NullPointerException("unit");
}
this.timer = timer;
if (timeout <= 0) {
timeoutMillis = 0;
} else {
timeoutMillis = Math.max(unit.toMillis(timeout), 1);
}
}
/**
* Stops the {@link Timer} which was specified in the constructor of this
* handler. You should not call this method if the {@link Timer} is in use
* by other objects.
*/
public void releaseExternalResources() {
timer.stop();
}
public void beforeAdd(ChannelHandlerContext ctx) throws Exception {
if (ctx.getPipeline().isAttached()) {
// channelOpen event has been fired already, which means
// this.channelOpen() will not be invoked.
// We have to initialize here instead.
initialize(ctx);
} else {
// channelOpen event has not been fired yet.
// this.channelOpen() will be invoked and initialization will occur there.
}
}
public void afterAdd(ChannelHandlerContext ctx) throws Exception {
// NOOP
}
public void beforeRemove(ChannelHandlerContext ctx) throws Exception {
destroy(ctx);
}
public void afterRemove(ChannelHandlerContext ctx) throws Exception {
// NOOP
}
@Override
public void channelOpen(ChannelHandlerContext ctx, ChannelStateEvent e)
throws Exception {
// This method will be invoked only if this handler was added
// before channelOpen event is fired. If a user adds this handler
// after the channelOpen event, initialize() will be called by beforeAdd().
initialize(ctx);
ctx.sendUpstream(e);
}
@Override
public void channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e)
throws Exception {
destroy(ctx);
ctx.sendUpstream(e);
}
@Override
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e)
throws Exception {
State state = (State) ctx.getAttachment();
state.lastReadTime = System.currentTimeMillis();
ctx.sendUpstream(e);
}
private void initialize(ChannelHandlerContext ctx) {
State state = state(ctx);
// Avoid the case where destroy() is called before scheduling timeouts.
// See: https://github.com/netty/netty/issues/143
synchronized (state) {
switch (state.state) {
case 1:
case 2:
return;
}
state.state = 1;
}
if (timeoutMillis > 0) {
state.timeout = timer.newTimeout(new ReadTimeoutTask(ctx), timeoutMillis, TimeUnit.MILLISECONDS);
}
}
private static void destroy(ChannelHandlerContext ctx) {
State state = state(ctx);
synchronized (state) {
if (state.state != 1) {
return;
}
state.state = 2;
}
if (state.timeout != null) {
state.timeout.cancel();
state.timeout = null;
}
}
private static State state(ChannelHandlerContext ctx) {
State state;
synchronized (ctx) {
// FIXME: It could have been better if there is setAttachmentIfAbsent().
state = (State) ctx.getAttachment();
if (state != null) {
return state;
}
state = new State();
ctx.setAttachment(state);
}
return state;
}
protected void readTimedOut(ChannelHandlerContext ctx) throws Exception {
fireExceptionCaught(ctx, EXCEPTION);
}
private final class ReadTimeoutTask implements TimerTask {
private final ChannelHandlerContext ctx;
ReadTimeoutTask(ChannelHandlerContext ctx) {
this.ctx = ctx;
}
public void run(Timeout timeout) throws Exception {
if (timeout.isCancelled()) {
return;
}
if (!ctx.getChannel().isOpen()) {
return;
}
State state = (State) ctx.getAttachment();
long currentTime = System.currentTimeMillis();
long nextDelay = timeoutMillis - (currentTime - state.lastReadTime);
if (nextDelay <= 0) {
// Read timed out - set a new timeout and notify the callback.
state.timeout =
timer.newTimeout(this, timeoutMillis, TimeUnit.MILLISECONDS);
fireReadTimedOut(ctx);
} else {
// Read occurred before the timeout - set a new timeout with shorter delay.
state.timeout =
timer.newTimeout(this, nextDelay, TimeUnit.MILLISECONDS);
}
}
private void fireReadTimedOut(final ChannelHandlerContext ctx) throws Exception {
ctx.getPipeline().execute(new Runnable() {
public void run() {
try {
readTimedOut(ctx);
} catch (Throwable t) {
fireExceptionCaught(ctx, t);
}
}
});
}
}
private static final class State {
// 0 - none, 1 - initialized, 2 - destroyed
int state;
volatile Timeout timeout;
volatile long lastReadTime = System.currentTimeMillis();
State() {
}
}
}