content: /**
   * 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 org.apache.activemq.broker.region.policy.SimpleDispatchSelector;
  import org.apache.activemq.command.ActiveMQDestination;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Queue dispatch policy that determines if a message can be sent to a subscription
   *
   * @org.apache.xbean.XBean
   *
   */
  public class QueueDispatchSelector extends SimpleDispatchSelector {
      private static final Logger LOG = LoggerFactory.getLogger(QueueDispatchSelector.class);
      private Subscription exclusiveConsumer;
      private volatile boolean paused;
  
      /**
       * @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 {
  
          boolean result = !paused && super.canDispatch(subscription, m);
          if (result && !subscription.isBrowser()) {
              result = exclusiveConsumer == null || exclusiveConsumer == subscription;
          }
          return result;
      }
  
      public void pause() {
          paused = true;
      }
  
      public void resume() {
          paused = false;
      }
  
      public boolean isPaused() {
          return paused;
      }
  }
  