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.policy;
018    
019    
020    import org.apache.activemq.Service;
021    import org.apache.activemq.broker.Broker;
022    import org.apache.activemq.broker.ConnectionContext;
023    import org.apache.activemq.broker.region.MessageReference;
024    import org.apache.activemq.broker.region.SubscriptionRecovery;
025    import org.apache.activemq.broker.region.Topic;
026    import org.apache.activemq.command.ActiveMQDestination;
027    import org.apache.activemq.command.Message;
028    
029    /**
030     * Abstraction to allow different recovery policies to be plugged
031     * into the region implementations.  This is used by a topic to retroactively recover
032     * messages that the subscription missed.
033     * 
034     * 
035     */
036    public interface SubscriptionRecoveryPolicy extends Service {
037        
038        /**
039         * A message was sent to the destination.
040         * 
041         * @param context
042         * @param message 
043         * @param node
044         * @return true if successful
045         * @throws Exception
046         */
047        boolean add(ConnectionContext context, MessageReference message) throws Exception;
048        
049        /**
050         * Let a subscription recover message held by the policy.
051         * 
052         * @param context
053         * @param topic
054         * @param sub 
055         * @param node
056         * @throws Exception
057         */
058        void recover(ConnectionContext context, Topic topic, SubscriptionRecovery sub) throws Exception;
059        
060        
061        /**
062         * @param dest 
063         * @return messages
064         * @throws Exception 
065         */
066        Message[] browse(ActiveMQDestination dest) throws Exception;
067    
068        /**
069         * Used to copy the policy object.
070         * @return the copy
071         */
072        SubscriptionRecoveryPolicy copy();
073        
074        void setBroker(Broker broker);
075    }