org.jboss.remoting3.util.MessageTracker Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* JBoss, Home of Professional Open Source.
* Copyright 2017 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* Licensed 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.remoting3.util;
import java.io.IOException;
import java.util.concurrent.atomic.AtomicBoolean;
import org.jboss.remoting3.AbstractDelegatingMessageOutputStream;
import org.jboss.remoting3.Channel;
import org.jboss.remoting3.MessageOutputStream;
import org.wildfly.common.Assert;
/**
* An outbound message tracker, which can be used to easily avoid message overruns.
*
* @author David M. Lloyd
*/
public final class MessageTracker {
private final Channel channel;
private final Object lock = new Object();
private int counter;
public MessageTracker(final Channel channel, final int limit) {
Assert.checkNotNullParam("channel", channel);
Assert.checkMinimumParameter("limit", 1, limit);
this.channel = channel;
counter = limit;
}
/**
* Open a message, blocking if necessary.
*
* @return the message stream
* @throws IOException if the channel failed to open the message
* @throws InterruptedException if blocking was interrupted
*/
public MessageOutputStream openMessage() throws IOException, InterruptedException {
final Object lock = this.lock;
int counter;
synchronized (lock) {
counter = this.counter;
while (counter == 0) {
lock.wait();
counter = this.counter;
}
this.counter = counter - 1;
}
return getMessageInstance(writeMessage());
}
/**
* Open a message, blocking if necessary, and deferring any interrupts which occur while blocking.
*
* @return the message stream
* @throws IOException if the channel failed to open the message
*/
public MessageOutputStream openMessageUninterruptibly() throws IOException {
final Object lock = this.lock;
boolean intr = false;
try {
int counter;
synchronized (lock) {
counter = this.counter;
while (counter == 0) {
try {
lock.wait();
} catch (InterruptedException ex) {
intr = true;
}
counter = this.counter;
}
this.counter = counter - 1;
}
return getMessageInstance(writeMessage());
} finally {
if (intr) Thread.currentThread().interrupt();
}
}
private MessageOutputStream writeMessage() throws IOException {
try {
return channel.writeMessage();
} catch (IOException e) {
final Object lock = this.lock;
synchronized (lock) {
this.counter ++;
lock.notify();
}
throw e;
}
}
private AbstractDelegatingMessageOutputStream getMessageInstance(final MessageOutputStream delegate) {
return new AbstractDelegatingMessageOutputStream(delegate) {
private final AtomicBoolean done = new AtomicBoolean();
public void close() throws IOException {
if (done.compareAndSet(false, true)) try {
super.close();
} finally {
final Object lock = MessageTracker.this.lock;
synchronized (lock) {
MessageTracker.this.counter ++;
lock.notify();
}
}
}
};
}
}