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 */
017package org.apache.activemq.broker.region.policy;
018
019import org.apache.activemq.broker.Broker;
020import org.apache.activemq.broker.region.DurableTopicSubscription;
021import org.apache.activemq.broker.region.cursors.PendingMessageCursor;
022import 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 */
033public 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}