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The ActiveMQ Message Broker and Client implementations
/**
* 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.policy;
import java.util.ArrayList;
import java.util.List;
import org.apache.activemq.broker.region.MessageReference;
import org.apache.activemq.broker.region.Subscription;
import org.apache.activemq.command.ConsumerId;
import org.apache.activemq.command.ConsumerInfo;
import org.apache.activemq.filter.MessageEvaluationContext;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* dispatch policy that ignores lower priority duplicate network consumers,
* used in conjunction with network bridge suppresDuplicateTopicSubscriptions
*
* @org.apache.xbean.XBean
*/
public class PriorityNetworkDispatchPolicy extends SimpleDispatchPolicy {
private static final Log LOG = LogFactory.getLog(PriorityNetworkDispatchPolicy.class);
@Override
public boolean dispatch(MessageReference node,
MessageEvaluationContext msgContext,
List consumers) throws Exception {
List duplicateFreeSubs = new ArrayList();
synchronized (consumers) {
for (Subscription sub: consumers) {
ConsumerInfo info = sub.getConsumerInfo();
if (info.isNetworkSubscription()) {
boolean highestPrioritySub = true;
for (Subscription candidate: duplicateFreeSubs) {
if (matches(candidate, info)) {
if (hasLowerPriority(candidate, info)) {
duplicateFreeSubs.remove(candidate);
} else {
// higher priority matching sub exists
highestPrioritySub = false;
if (LOG.isDebugEnabled()) {
LOG.debug("ignoring lower priority: " + candidate
+ "[" +candidate.getConsumerInfo().getNetworkConsumerIds() +", "
+ candidate.getConsumerInfo().getNetworkConsumerIds() +"] in favour of: "
+ sub
+ "[" +sub.getConsumerInfo().getNetworkConsumerIds() +", "
+ sub.getConsumerInfo().getNetworkConsumerIds() +"]");
}
}
}
}
if (highestPrioritySub) {
duplicateFreeSubs.add(sub);
}
} else {
duplicateFreeSubs.add(sub);
}
}
}
return super.dispatch(node, msgContext, duplicateFreeSubs);
}
private boolean hasLowerPriority(Subscription candidate,
ConsumerInfo info) {
return candidate.getConsumerInfo().getPriority() < info.getPriority();
}
private boolean matches(Subscription candidate, ConsumerInfo info) {
boolean matched = false;
for (ConsumerId candidateId: candidate.getConsumerInfo().getNetworkConsumerIds()) {
for (ConsumerId subId: info.getNetworkConsumerIds()) {
if (candidateId.equals(subId)) {
matched = true;
break;
}
}
}
return matched;
}
}