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/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.activemq.transport;
import java.io.IOException;
import java.util.Timer;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.apache.activemq.command.KeepAliveInfo;
import org.apache.activemq.command.WireFormatInfo;
import org.apache.activemq.thread.SchedulerTimerTask;
import org.apache.activemq.util.ThreadPoolUtils;
import org.apache.activemq.wireformat.WireFormat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Used to make sure that commands are arriving periodically from the peer of
* the transport.
*/
public abstract class AbstractInactivityMonitor extends TransportFilter {
private static final Logger LOG = LoggerFactory.getLogger(AbstractInactivityMonitor.class);
private static ThreadPoolExecutor ASYNC_TASKS;
private static int CHECKER_COUNTER;
private static long DEFAULT_CHECK_TIME_MILLS = 30000;
private static Timer READ_CHECK_TIMER;
private static Timer WRITE_CHECK_TIMER;
private final AtomicBoolean monitorStarted = new AtomicBoolean(false);
private final AtomicBoolean commandSent = new AtomicBoolean(false);
private final AtomicBoolean inSend = new AtomicBoolean(false);
private final AtomicBoolean failed = new AtomicBoolean(false);
private final AtomicBoolean commandReceived = new AtomicBoolean(true);
private final AtomicBoolean inReceive = new AtomicBoolean(false);
private final AtomicInteger lastReceiveCounter = new AtomicInteger(0);
private final ReentrantReadWriteLock sendLock = new ReentrantReadWriteLock();
private SchedulerTimerTask writeCheckerTask;
private SchedulerTimerTask readCheckerTask;
private long readCheckTime = DEFAULT_CHECK_TIME_MILLS;
private long writeCheckTime = DEFAULT_CHECK_TIME_MILLS;
private long initialDelayTime = DEFAULT_CHECK_TIME_MILLS;
private boolean useKeepAlive = true;
private boolean keepAliveResponseRequired;
protected WireFormat wireFormat;
private final Runnable readChecker = new Runnable() {
long lastRunTime;
@Override
public void run() {
long now = System.currentTimeMillis();
long elapsed = (now - lastRunTime);
if (lastRunTime != 0) {
LOG.debug("{}ms elapsed since last read check.", elapsed);
}
// Perhaps the timer executed a read check late.. and then executes
// the next read check on time which causes the time elapsed between
// read checks to be small..
// If less than 90% of the read check Time elapsed then abort this
// read check.
if (!allowReadCheck(elapsed)) {
LOG.debug("Aborting read check...Not enough time elapsed since last read check.");
return;
}
lastRunTime = now;
readCheck();
}
@Override
public String toString() {
return "ReadChecker";
}
};
private boolean allowReadCheck(long elapsed) {
return elapsed > (readCheckTime * 9 / 10);
}
private final Runnable writeChecker = new Runnable() {
long lastRunTime;
@Override
public void run() {
long now = System.currentTimeMillis();
if (lastRunTime != 0) {
LOG.debug("{}: {}ms elapsed since last write check.", this, (now - lastRunTime));
}
lastRunTime = now;
writeCheck();
}
@Override
public String toString() {
return "WriteChecker";
}
};
public AbstractInactivityMonitor(Transport next, WireFormat wireFormat) {
super(next);
this.wireFormat = wireFormat;
}
@Override
public void start() throws Exception {
next.start();
startMonitorThreads();
}
@Override
public void stop() throws Exception {
stopMonitorThreads();
next.stop();
}
final void writeCheck() {
if (inSend.get()) {
LOG.trace("Send in progress. Skipping write check.");
return;
}
if (!commandSent.get() && useKeepAlive && monitorStarted.get() && !ASYNC_TASKS.isTerminating() && !ASYNC_TASKS.isTerminated()) {
LOG.trace("{} no message sent since last write check, sending a KeepAliveInfo", this);
try {
ASYNC_TASKS.execute(new Runnable() {
@Override
public void run() {
LOG.debug("Running {}", this);
if (monitorStarted.get()) {
try {
// If we can't get the lock it means another
// write beat us into the
// send and we don't need to heart beat now.
if (sendLock.writeLock().tryLock()) {
KeepAliveInfo info = new KeepAliveInfo();
info.setResponseRequired(keepAliveResponseRequired);
doOnewaySend(info);
}
} catch (IOException e) {
onException(e);
} finally {
if (sendLock.writeLock().isHeldByCurrentThread()) {
sendLock.writeLock().unlock();
}
}
}
}
@Override
public String toString() {
return "WriteCheck[" + getRemoteAddress() + "]";
};
});
} catch (RejectedExecutionException ex) {
if (!ASYNC_TASKS.isTerminating() && !ASYNC_TASKS.isTerminated()) {
LOG.error("Async write check was rejected from the executor: ", ex);
throw ex;
}
}
} else {
LOG.trace("{} message sent since last write check, resetting flag.", this);
}
commandSent.set(false);
}
final void readCheck() {
int currentCounter = next.getReceiveCounter();
int previousCounter = lastReceiveCounter.getAndSet(currentCounter);
if (inReceive.get() || currentCounter != previousCounter) {
LOG.trace("A receive is in progress, skipping read check.");
return;
}
if (!commandReceived.get() && monitorStarted.get() && !ASYNC_TASKS.isTerminating() && !ASYNC_TASKS.isTerminated()) {
LOG.debug("No message received since last read check for {}. Throwing InactivityIOException.", this);
try {
ASYNC_TASKS.execute(new Runnable() {
@Override
public void run() {
LOG.debug("Running {}", this);
onException(new InactivityIOException("Channel was inactive for too (>" + readCheckTime + ") long: " + next.getRemoteAddress()));
}
@Override
public String toString() {
return "ReadCheck[" + getRemoteAddress() + "]";
};
});
} catch (RejectedExecutionException ex) {
if (!ASYNC_TASKS.isTerminating() && !ASYNC_TASKS.isTerminated()) {
LOG.error("Async read check was rejected from the executor: ", ex);
throw ex;
}
}
} else {
if (LOG.isTraceEnabled()) {
LOG.trace("Message received since last read check, resetting flag: ");
}
}
commandReceived.set(false);
}
protected abstract void processInboundWireFormatInfo(WireFormatInfo info) throws IOException;
protected abstract void processOutboundWireFormatInfo(WireFormatInfo info) throws IOException;
@Override
public void onCommand(Object command) {
commandReceived.set(true);
inReceive.set(true);
try {
if (command.getClass() == KeepAliveInfo.class) {
KeepAliveInfo info = (KeepAliveInfo) command;
if (info.isResponseRequired()) {
sendLock.readLock().lock();
try {
info.setResponseRequired(false);
oneway(info);
} catch (IOException e) {
onException(e);
} finally {
sendLock.readLock().unlock();
}
}
} else {
if (command.getClass() == WireFormatInfo.class) {
synchronized (this) {
try {
processInboundWireFormatInfo((WireFormatInfo) command);
} catch (IOException e) {
onException(e);
}
}
}
transportListener.onCommand(command);
}
} finally {
inReceive.set(false);
}
}
@Override
public void oneway(Object o) throws IOException {
// To prevent the inactivity monitor from sending a message while we
// are performing a send we take a read lock. The inactivity monitor
// sends its Heart-beat commands under a write lock. This means that
// the MutexTransport is still responsible for synchronizing sends
this.sendLock.readLock().lock();
inSend.set(true);
try {
doOnewaySend(o);
} finally {
commandSent.set(true);
inSend.set(false);
this.sendLock.readLock().unlock();
}
}
// Must be called under lock, either read or write on sendLock.
private void doOnewaySend(Object command) throws IOException {
if (failed.get()) {
throw new InactivityIOException("Cannot send, channel has already failed: " + next.getRemoteAddress());
}
if (command.getClass() == WireFormatInfo.class) {
synchronized (this) {
processOutboundWireFormatInfo((WireFormatInfo) command);
}
}
next.oneway(command);
}
@Override
public void onException(IOException error) {
if (failed.compareAndSet(false, true)) {
stopMonitorThreads();
if (sendLock.writeLock().isHeldByCurrentThread()) {
sendLock.writeLock().unlock();
}
transportListener.onException(error);
}
}
public void setUseKeepAlive(boolean val) {
useKeepAlive = val;
}
public long getReadCheckTime() {
return readCheckTime;
}
public void setReadCheckTime(long readCheckTime) {
this.readCheckTime = readCheckTime;
}
public long getWriteCheckTime() {
return writeCheckTime;
}
public void setWriteCheckTime(long writeCheckTime) {
this.writeCheckTime = writeCheckTime;
}
public long getInitialDelayTime() {
return initialDelayTime;
}
public void setInitialDelayTime(long initialDelayTime) {
this.initialDelayTime = initialDelayTime;
}
public boolean isKeepAliveResponseRequired() {
return this.keepAliveResponseRequired;
}
public void setKeepAliveResponseRequired(boolean value) {
this.keepAliveResponseRequired = value;
}
public boolean isMonitorStarted() {
return this.monitorStarted.get();
}
protected synchronized void startMonitorThreads() throws IOException {
if (monitorStarted.get()) {
return;
}
if (!configuredOk()) {
return;
}
if (readCheckTime > 0) {
readCheckerTask = new SchedulerTimerTask(readChecker);
}
if (writeCheckTime > 0) {
writeCheckerTask = new SchedulerTimerTask(writeChecker);
}
if (writeCheckTime > 0 || readCheckTime > 0) {
monitorStarted.set(true);
synchronized (AbstractInactivityMonitor.class) {
if (CHECKER_COUNTER == 0) {
ASYNC_TASKS = createExecutor();
READ_CHECK_TIMER = new Timer("ActiveMQ InactivityMonitor ReadCheckTimer", true);
WRITE_CHECK_TIMER = new Timer("ActiveMQ InactivityMonitor WriteCheckTimer", true);
}
CHECKER_COUNTER++;
if (readCheckTime > 0) {
READ_CHECK_TIMER.schedule(readCheckerTask, initialDelayTime, readCheckTime);
}
if (writeCheckTime > 0) {
WRITE_CHECK_TIMER.schedule(writeCheckerTask, initialDelayTime, writeCheckTime);
}
}
}
}
abstract protected boolean configuredOk() throws IOException;
protected synchronized void stopMonitorThreads() {
if (monitorStarted.compareAndSet(true, false)) {
if (readCheckerTask != null) {
readCheckerTask.cancel();
}
if (writeCheckerTask != null) {
writeCheckerTask.cancel();
}
synchronized (AbstractInactivityMonitor.class) {
WRITE_CHECK_TIMER.purge();
READ_CHECK_TIMER.purge();
CHECKER_COUNTER--;
if (CHECKER_COUNTER == 0) {
WRITE_CHECK_TIMER.cancel();
READ_CHECK_TIMER.cancel();
WRITE_CHECK_TIMER = null;
READ_CHECK_TIMER = null;
ThreadPoolUtils.shutdown(ASYNC_TASKS);
}
}
}
}
private final ThreadFactory factory = new ThreadFactory() {
@Override
public Thread newThread(Runnable runnable) {
Thread thread = new Thread(runnable, "ActiveMQ InactivityMonitor Worker");
thread.setDaemon(true);
return thread;
}
};
private ThreadPoolExecutor createExecutor() {
ThreadPoolExecutor exec = new ThreadPoolExecutor(0, Integer.MAX_VALUE, getDefaultKeepAliveTime(), TimeUnit.SECONDS, new SynchronousQueue(), factory);
exec.allowCoreThreadTimeOut(true);
return exec;
}
private static int getDefaultKeepAliveTime() {
return Integer.getInteger("org.apache.activemq.transport.AbstractInactivityMonitor.keepAliveTime", 30);
}
}