/*
* JBoss, Home of Professional Open Source.
* Copyright 2014, Red Hat, Inc., and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.as.domain.http.server;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import org.jboss.as.domain.http.server.logging.HttpServerLogger;
import org.jboss.as.protocol.mgmt.support.ManagementChannelShutdownHandle;
/**
* This class tracks active http management requests and provides listeners to coordinate the shutdown of the server. Its
* main purpose is in conjunction with the {@code HttpShutdownService} and the {@code ManagementRequestTracker},
* which prevent the http server from closing the connections before all active operations completed.
*
* @author Emanuel Muckenhuber
*/
public class ManagementHttpRequestProcessor implements ManagementChannelShutdownHandle {
private volatile int state;
private final List<ShutdownListener> listeners = new ArrayList<>();
private static final int CLOSED = 1 << 31;
private volatile CountDownLatch latch = new CountDownLatch(1);
private static final AtomicIntegerFieldUpdater<ManagementHttpRequestProcessor> stateUpdater = AtomicIntegerFieldUpdater.newUpdater(ManagementHttpRequestProcessor.class, "state");
@Override
public void shutdown() {
prepareShutdown();
}
@Override
public void shutdownNow() {
prepareShutdown();
}
@Override
public boolean awaitCompletion(long timeout, TimeUnit unit) throws InterruptedException {
boolean completed = latch.await(timeout, unit);
if (!completed) {
HttpServerLogger.ROOT_LOGGER.debugf("ShutdownListener(s) %s have not completed within %d %s", listeners, timeout, unit);
}
return completed;
}
/**
* Prepare the shutdown, disallowing new requests.
*/
// This gets called in HttpShutdownService#stop() to signal that the server is about to stop
void prepareShutdown() {
int oldState, newState;
do {
oldState = state;
if ((oldState & CLOSED) != 0) {
return;
}
newState = oldState | CLOSED;
} while (!stateUpdater.compareAndSet(this, oldState, newState));
// If there no active requests notify listeners directly
if (newState == CLOSED) {
handleCompleted();
}
}
/**
* Add a shutdown listener, which gets called when all requests completed on shutdown.
*
* @param listener the shutdown listener
*/
public synchronized void addShutdownListener(ShutdownListener listener) {
if (state == CLOSED) {
listener.handleCompleted();
} else {
listeners.add(listener);
}
}
/**
* Notify all shutdown listeners that the shutdown completed.
*/
protected synchronized void handleCompleted() {
latch.countDown();
for (final ShutdownListener listener : listeners) {
listener.handleCompleted();
}
listeners.clear();
}
/**
* This gets called when we receive a new http mgmt request and returns whether
* the request can process or should return a {@code 503} response when the server
* is about to shutdown.
*
* @return {@code true} if the request can be processed; {@code false} if the server is about to shut down
*/
protected boolean beginRequest() {
int oldState, newState;
for (;;) {
oldState = state;
if ((oldState & CLOSED) != 0) {
return false;
}
newState = oldState + 1;
if (newState == Integer.MAX_VALUE) {
return false;
}
if (stateUpdater.compareAndSet(this, oldState, newState)) {
return true;
}
}
}
/**
* End a request and call the {@link #handleCompleted()} if the server is
* shutdown and there are no more active requests.
*/
protected void endRequest() {
int oldState, newState;
do {
oldState = state;
newState = oldState - 1;
} while (!stateUpdater.compareAndSet(this, oldState, newState));
if (newState == CLOSED) {
handleCompleted();
}
}
public interface ShutdownListener {
void handleCompleted();
}
}