/**
* 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;
import java.io.IOException;
import java.util.List;
import javax.jms.JMSException;
import org.apache.activemq.broker.region.group.MessageGroupMap;
import org.apache.activemq.broker.region.policy.SimpleDispatchSelector;
import org.apache.activemq.command.ActiveMQDestination;
import org.apache.activemq.command.ActiveMQMessage;
import org.apache.activemq.command.ConsumerId;
import org.apache.activemq.command.Message;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* Queue dispatch policy that determines if a message can be sent to a subscription
*
* @org.apache.xbean.XBean
* @version $Revision$
*/
public class QueueDispatchSelector extends SimpleDispatchSelector {
private static final Log LOG = LogFactory.getLog(QueueDispatchSelector.class);
private Subscription exclusiveConsumer;
/**
* @param destination
*/
public QueueDispatchSelector(ActiveMQDestination destination) {
super(destination);
}
public Subscription getExclusiveConsumer() {
return exclusiveConsumer;
}
public void setExclusiveConsumer(Subscription exclusiveConsumer) {
this.exclusiveConsumer = exclusiveConsumer;
}
public boolean isExclusiveConsumer(Subscription s) {
return s == this.exclusiveConsumer;
}
public boolean canSelect(Subscription subscription,
MessageReference m) throws Exception {
if (subscription.isBrowser() && super.canDispatch(subscription, m)) {
return true;
}
boolean result = super.canDispatch(subscription, m) ;
if (result) {
result = exclusiveConsumer == null
|| exclusiveConsumer == subscription;
if (result) {
QueueMessageReference node = (QueueMessageReference) m;
// Keep message groups together.
String groupId = node.getGroupID();
int sequence = node.getGroupSequence();
if (groupId != null) {
MessageGroupMap messageGroupOwners = ((Queue) node
.getRegionDestination()).getMessageGroupOwners();
// If we can own the first, then no-one else should own the
// rest.
if (sequence == 1) {
assignGroup(subscription, messageGroupOwners, node,groupId);
}else {
// Make sure that the previous owner is still valid, we may
// need to become the new owner.
ConsumerId groupOwner;
groupOwner = messageGroupOwners.get(groupId);
if (groupOwner == null) {
assignGroup(subscription, messageGroupOwners, node,groupId);
} else {
if (groupOwner.equals(subscription.getConsumerInfo().getConsumerId())) {
// A group sequence < 1 is an end of group signal.
if (sequence < 0) {
messageGroupOwners.removeGroup(groupId);
}
} else {
result = false;
}
}
}
}
}
}
return result;
}
protected void assignGroup(Subscription subs,MessageGroupMap messageGroupOwners, MessageReference n, String groupId) throws IOException {
messageGroupOwners.put(groupId, subs.getConsumerInfo().getConsumerId());
Message message = n.getMessage();
if (message instanceof ActiveMQMessage) {
ActiveMQMessage activeMessage = (ActiveMQMessage)message;
try {
activeMessage.setBooleanProperty("JMSXGroupFirstForConsumer", true, false);
} catch (JMSException e) {
LOG.warn("Failed to set boolean header: " + e, e);
}
}
}
}