components/camel-jms/src/main/java/org/apache/camel/component/jms/reply/SharedQueueMessageListenerContainer.java

/**
 * 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.camel.component.jms.reply;

import org.apache.camel.component.jms.DefaultJmsMessageListenerContainer;
import org.apache.camel.component.jms.JmsEndpoint;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.jms.listener.DefaultMessageListenerContainer;

/**
 * This {@link DefaultMessageListenerContainer} is used for reply queues which are shared.
 * <p/>
 * This implementation supports using a fixed or dynamic JMS Message Selector to pickup the
 * designated reply messages from the shared queue. Since the queue is shared, then we can only
 * pickup the reply messages which is intended for us, so to support that we must use JMS
 * Message Selectors.
 * <p/>
 * See more details at <a href="http://camel.apache.org/jms">camel-jms</a>.
 *
 * @see ExclusiveQueueMessageListenerContainer
 */
public class SharedQueueMessageListenerContainer extends DefaultJmsMessageListenerContainer {

    private static final Logger LOG = LoggerFactory.getLogger(SharedQueueMessageListenerContainer.class);

    private String fixedMessageSelector;
    private MessageSelectorCreator creator;

    /**
     * Use a fixed JMS message selector
     *
     * @param endpoint the endpoint
     * @param fixedMessageSelector the fixed selector
     */
    public SharedQueueMessageListenerContainer(JmsEndpoint endpoint, String fixedMessageSelector) {
        super(endpoint, endpoint.isAllowReplyManagerQuickStop());
        this.fixedMessageSelector = fixedMessageSelector;
    }

    /**
     * Use a dynamic JMS message selector
     *
     * @param endpoint the endpoint
     * @param creator the create to create the dynamic selector
     */
    public SharedQueueMessageListenerContainer(JmsEndpoint endpoint, MessageSelectorCreator creator) {
        super(endpoint, endpoint.isAllowReplyManagerQuickStop());
        this.creator = creator;
    }

    @Override
    public String getMessageSelector() {
        // override this method and return the appropriate selector
        String id = null;
        if (fixedMessageSelector != null) {
            id = fixedMessageSelector;
        } else if (creator != null) {
            id = creator.get();
        }
        LOG.trace("Using MessageSelector[{}]", id);
        return id;
    }

}