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