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 java.util.Iterator; 020import java.util.List; 021import org.apache.activemq.broker.Broker; 022import org.apache.activemq.broker.ConnectionContext; 023import org.apache.activemq.broker.region.MessageReference; 024import org.apache.activemq.broker.region.SubscriptionRecovery; 025import org.apache.activemq.broker.region.Topic; 026import org.apache.activemq.command.ActiveMQDestination; 027import org.apache.activemq.command.Message; 028import org.apache.activemq.memory.list.DestinationBasedMessageList; 029import org.apache.activemq.memory.list.MessageList; 030import org.apache.activemq.memory.list.SimpleMessageList; 031 032/** 033 * This implementation of {@link SubscriptionRecoveryPolicy} will keep a fixed 034 * amount of memory available in RAM for message history which is evicted in 035 * time order. 036 * 037 * @org.apache.xbean.XBean 038 * 039 */ 040public class FixedSizedSubscriptionRecoveryPolicy implements SubscriptionRecoveryPolicy { 041 042 private MessageList buffer; 043 private int maximumSize = 64 * 1024; 044 private boolean useSharedBuffer = true; 045 046 public FixedSizedSubscriptionRecoveryPolicy() { 047 048 } 049 050 public SubscriptionRecoveryPolicy copy() { 051 FixedSizedSubscriptionRecoveryPolicy rc = new FixedSizedSubscriptionRecoveryPolicy(); 052 rc.setMaximumSize(maximumSize); 053 rc.setUseSharedBuffer(useSharedBuffer); 054 return rc; 055 } 056 057 public boolean add(ConnectionContext context, MessageReference message) throws Exception { 058 buffer.add(message); 059 return true; 060 } 061 062 public void recover(ConnectionContext context, Topic topic, SubscriptionRecovery sub) throws Exception { 063 // Re-dispatch the messages from the buffer. 064 List copy = buffer.getMessages(sub.getActiveMQDestination()); 065 if (!copy.isEmpty()) { 066 for (Iterator iter = copy.iterator(); iter.hasNext();) { 067 MessageReference node = (MessageReference)iter.next(); 068 sub.addRecoveredMessage(context, node); 069 } 070 } 071 } 072 073 public void start() throws Exception { 074 buffer = createMessageList(); 075 } 076 077 public void stop() throws Exception { 078 buffer.clear(); 079 } 080 081 // Properties 082 // ------------------------------------------------------------------------- 083 public MessageList getBuffer() { 084 return buffer; 085 } 086 087 public void setBuffer(MessageList buffer) { 088 this.buffer = buffer; 089 } 090 091 public int getMaximumSize() { 092 return maximumSize; 093 } 094 095 /** 096 * Sets the maximum amount of RAM in bytes that this buffer can hold in RAM 097 */ 098 public void setMaximumSize(int maximumSize) { 099 this.maximumSize = maximumSize; 100 } 101 102 public boolean isUseSharedBuffer() { 103 return useSharedBuffer; 104 } 105 106 public void setUseSharedBuffer(boolean useSharedBuffer) { 107 this.useSharedBuffer = useSharedBuffer; 108 } 109 110 public Message[] browse(ActiveMQDestination destination) throws Exception { 111 return buffer.browse(destination); 112 } 113 114 public void setBroker(Broker broker) { 115 } 116 117 // Implementation methods 118 119 // ------------------------------------------------------------------------- 120 protected MessageList createMessageList() { 121 if (useSharedBuffer) { 122 return new SimpleMessageList(maximumSize); 123 } else { 124 return new DestinationBasedMessageList(maximumSize); 125 } 126 } 127 128}