org.apache.activemq.broker.region.virtual.SelectorAwareVirtualTopicInterceptor Maven / Gradle / Ivy
/**
* 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.broker.region.virtual;
import org.apache.activemq.broker.Broker;
import org.apache.activemq.broker.region.Destination;
import org.apache.activemq.broker.region.Subscription;
import org.apache.activemq.broker.region.Topic;
import org.apache.activemq.command.Message;
import org.apache.activemq.filter.BooleanExpression;
import org.apache.activemq.filter.MessageEvaluationContext;
import org.apache.activemq.filter.NonCachedMessageEvaluationContext;
import org.apache.activemq.plugin.SubQueueSelectorCacheBroker;
import org.apache.activemq.selector.SelectorParser;
import org.apache.activemq.util.LRUCache;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.List;
import java.util.Set;
public class SelectorAwareVirtualTopicInterceptor extends VirtualTopicInterceptor {
private static final Logger LOG = LoggerFactory.getLogger(SelectorAwareVirtualTopicInterceptor.class);
LRUCache expressionCache = new LRUCache();
private final SubQueueSelectorCacheBroker selectorCachePlugin;
public SelectorAwareVirtualTopicInterceptor(Destination next, VirtualTopic virtualTopic) {
super(next, virtualTopic);
selectorCachePlugin = (SubQueueSelectorCacheBroker)
((Topic)next).createConnectionContext().getBroker().getAdaptor(SubQueueSelectorCacheBroker.class);
}
/**
* Respect the selectors of the subscriptions to ensure only matched messages are dispatched to
* the virtual queues, hence there is no build up of unmatched messages on these destinations
*/
@Override
protected boolean shouldDispatch(final Broker broker, Message message, Destination dest) throws IOException {
//first validate that the prefix matches in the super class
if (super.shouldDispatch(broker, message, dest)) {
boolean matches = false;
MessageEvaluationContext msgContext = new NonCachedMessageEvaluationContext();
msgContext.setDestination(dest.getActiveMQDestination());
msgContext.setMessageReference(message);
List subs = dest.getConsumers();
for (Subscription sub : subs) {
if (sub.matches(message, msgContext)) {
matches = true;
break;
}
}
if (matches == false) {
matches = tryMatchingCachedSubs(broker, dest, msgContext);
}
return matches;
}
return false;
}
private boolean tryMatchingCachedSubs(final Broker broker, Destination dest, MessageEvaluationContext msgContext) {
boolean matches = false;
LOG.debug("No active consumer match found. Will try cache if configured...");
if (selectorCachePlugin != null) {
final Set selectors = selectorCachePlugin.getSelectorsForDestination(dest.getActiveMQDestination().getQualifiedName());
if (selectors != null) {
for (String selector : selectors) {
try {
final BooleanExpression expression = getExpression(selector);
matches = expression.matches(msgContext);
if (matches) {
return true;
}
} catch (Exception e) {
LOG.error(e.getMessage(), e);
}
}
}
}
return matches;
}
private BooleanExpression getExpression(String selector) throws Exception{
BooleanExpression result;
synchronized(expressionCache){
result = expressionCache.get(selector);
if (result == null){
result = compileSelector(selector);
expressionCache.put(selector,result);
}
}
return result;
}
/**
* Pre-compile the JMS selector.
*
* @param selectorExpression The non-null JMS selector expression.
*/
private BooleanExpression compileSelector(final String selectorExpression) throws Exception {
return SelectorParser.parse(selectorExpression);
}
}