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    import org.apache.activemq.broker.Broker;
020    import org.apache.activemq.broker.region.DurableTopicSubscription;
021    import org.apache.activemq.broker.region.Subscription;
022    import org.apache.activemq.broker.region.cursors.PendingMessageCursor;
023    import org.apache.activemq.broker.region.cursors.StoreDurableSubscriberCursor;
024    import org.apache.activemq.kaha.Store;
025    
026    /**
027     * Creates a PendingMessageCursor that access the persistent store to retrieve
028     * messages
029     * 
030     * @org.apache.xbean.XBean element="storeDurableSubscriberCursor"
031     *                         description="Pending messages for a durable
032     *                         subscriber are referenced from the Store"
033     * 
034     */
035    public class StorePendingDurableSubscriberMessageStoragePolicy implements PendingDurableSubscriberMessageStoragePolicy {
036        boolean immediatePriorityDispatch = true;
037        boolean useCache = true;
038    
039        public boolean isImmediatePriorityDispatch() {
040            return immediatePriorityDispatch;
041        }
042    
043        /**
044         * Ensure that new higher priority messages will get an immediate dispatch
045         * rather than wait for the end of the current cursor batch.
046         * Useful when there is a large message backlog and intermittent high priority messages.
047         *
048         * @param immediatePriorityDispatch
049         */
050        public void setImmediatePriorityDispatch(boolean immediatePriorityDispatch) {
051            this.immediatePriorityDispatch = immediatePriorityDispatch;
052        }
053    
054        public boolean isUseCache() {
055            return useCache;
056        }
057    
058        public void setUseCache(boolean useCache) {
059            this.useCache = useCache;
060        }
061    
062        /**
063         * Retrieve the configured pending message storage cursor;
064         * @param broker 
065         * 
066         * @param clientId
067         * @param name
068         * @param maxBatchSize
069         * @param sub 
070         * @return the Pending Message cursor
071         */
072        public PendingMessageCursor getSubscriberPendingMessageCursor(Broker broker,String clientId, String name, int maxBatchSize, DurableTopicSubscription sub) {
073            StoreDurableSubscriberCursor cursor = new StoreDurableSubscriberCursor(broker,clientId, name, maxBatchSize, sub);
074            cursor.setUseCache(isUseCache());
075            cursor.setImmediatePriorityDispatch(isImmediatePriorityDispatch());
076            return cursor;
077        }
078    }