/**
 * 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 org.apache.activemq.command.ConsumerId;
import org.apache.activemq.command.Message;
import org.apache.activemq.command.MessageId;

/**
 * Keeps track of a message that is flowing through the Broker.  This 
 * object may hold a hard reference to the message or only hold the
 * id of the message if the message has been persisted on in a MessageStore.
 * 
 * @version $Revision: 1.15 $
 */
public interface MessageReference {
    
    MessageId getMessageId();
    Message getMessageHardRef();
    Message getMessage() throws IOException;
    boolean isPersistent();
    
    Destination getRegionDestination();
    
    int getRedeliveryCounter();
    void incrementRedeliveryCounter();
    
    int getReferenceCount();
    
    int incrementReferenceCount();
    int decrementReferenceCount();
    ConsumerId getTargetConsumerId();
    int getSize();
    long getExpiration();
    String getGroupID();
    int getGroupSequence();
    
    /**
     * Returns true if this message is expired
     */
    boolean isExpired();

    /**
     * Returns true if this message is dropped.
     */
    boolean isDropped();
    
    /**
     * @return true if the message is an advisory
     */
    boolean isAdvisory();
    
}
