001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.activemq.broker.region;
018    
019    /**
020     * Queue specific MessageReference.
021     * 
022     * @author fateev@amazon.com
023     * 
024     */
025    public interface QueueMessageReference extends MessageReference {
026    
027        QueueMessageReference NULL_MESSAGE = new NullMessageReference();
028    
029        boolean isAcked();
030        
031        void setAcked(boolean b);
032        
033        void drop();
034     
035        boolean isDropped();
036            
037        boolean lock(LockOwner subscription);
038        
039        boolean unlock();
040        
041        LockOwner getLockOwner();
042    }