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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.tomcat.websocket.server;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.ConcurrentSkipListSet;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.tomcat.websocket.BackgroundProcess;
import org.apache.tomcat.websocket.BackgroundProcessManager;
/**
* Provides timeouts for asynchronous web socket writes. On the server side we
* only have access to {@link javax.servlet.ServletOutputStream} and
* {@link javax.servlet.ServletInputStream} so there is no way to set a timeout
* for writes to the client.
*/
public class WsWriteTimeout implements BackgroundProcess {
private final Set<WsRemoteEndpointImplServer> endpoints =
new ConcurrentSkipListSet<WsRemoteEndpointImplServer>(new EndpointComparator());
private final AtomicInteger count = new AtomicInteger(0);
private int backgroundProcessCount = 0;
private volatile int processPeriod = 1;
@Override
public void backgroundProcess() {
// This method gets called once a second.
backgroundProcessCount ++;
if (backgroundProcessCount >= processPeriod) {
backgroundProcessCount = 0;
long now = System.currentTimeMillis();
Iterator<WsRemoteEndpointImplServer> iter = endpoints.iterator();
while (iter.hasNext()) {
WsRemoteEndpointImplServer endpoint = iter.next();
if (endpoint.getTimeoutExpiry() < now) {
// Background thread, not the thread that triggered the
// write so no need to use a dispatch
endpoint.onTimeout(false);
} else {
// Endpoints are ordered by timeout expiry so if this point
// is reached there is no need to check the remaining
// endpoints
break;
}
}
}
}
@Override
public void setProcessPeriod(int period) {
this.processPeriod = period;
}
/**
* {@inheritDoc}
*
* The default value is 1 which means asynchronous write timeouts are
* processed every 1 second.
*/
@Override
public int getProcessPeriod() {
return processPeriod;
}
public void register(WsRemoteEndpointImplServer endpoint) {
boolean result = endpoints.add(endpoint);
if (result) {
int newCount = count.incrementAndGet();
if (newCount == 1) {
BackgroundProcessManager.getInstance().register(this);
}
}
}
public void unregister(WsRemoteEndpointImplServer endpoint) {
boolean result = endpoints.remove(endpoint);
if (result) {
int newCount = count.decrementAndGet();
if (newCount == 0) {
BackgroundProcessManager.getInstance().unregister(this);
}
}
}
/**
* Note: this comparator imposes orderings that are inconsistent with equals
*/
private static class EndpointComparator implements
Comparator<WsRemoteEndpointImplServer> {
@Override
public int compare(WsRemoteEndpointImplServer o1,
WsRemoteEndpointImplServer o2) {
long t1 = o1.getTimeoutExpiry();
long t2 = o2.getTimeoutExpiry();
if (t1 < t2) {
return -1;
} else if (t1 == t2) {
return 0;
} else {
return 1;
}
}
}
}
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