Save This Page
Home » activemq-parent-5.3.1-source-release » org.apache » activemq » broker » region » policy » [javadoc | source]
    1   /**
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
   10    *
   11    * Unless required by applicable law or agreed to in writing, software
   12    * distributed under the License is distributed on an "AS IS" BASIS,
   13    * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   14    * See the License for the specific language governing permissions and
   15    * limitations under the License.
   16    */
   17   package org.apache.activemq.broker.region.policy;
   18   
   19   import java.io.IOException;
   20   import java.util.Iterator;
   21   import java.util.LinkedList;
   22   
   23   import org.apache.activemq.broker.region.MessageReference;
   24   
   25   /**
   26    * An eviction strategy which evicts the oldest message with the lowest priority first.
   27    * 
   28    * @org.apache.xbean.XBean
   29    * 
   30    * @version $Revision: 564057 $messageEvictionStrategy
   31    */
   32   public class OldestMessageWithLowestPriorityEvictionStrategy extends MessageEvictionStrategySupport {
   33   
   34       public MessageReference[] evictMessages(LinkedList messages) throws IOException {
   35           byte lowestPriority = Byte.MAX_VALUE;
   36           int pivot = 0;
   37           Iterator iter = messages.iterator();
   38           for (int i = 0; iter.hasNext(); i++) {
   39               MessageReference reference = (MessageReference) iter.next();
   40               byte priority = reference.getMessage().getPriority();
   41               if (priority < lowestPriority) {
   42                   lowestPriority = priority;
   43                   pivot = i;
   44               }
   45           }
   46           return new MessageReference[] {(MessageReference) messages.remove(pivot)};
   47       }
   48   }

Save This Page
Home » activemq-parent-5.3.1-source-release » org.apache » activemq » broker » region » policy » [javadoc | source]