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.cursors; 018 019import java.util.ArrayList; 020import java.util.Collection; 021import java.util.HashMap; 022import java.util.Iterator; 023import java.util.List; 024import java.util.Map; 025import org.apache.activemq.broker.region.MessageReference; 026import org.apache.activemq.command.MessageId; 027 028public class OrderedPendingList implements PendingList { 029 030 private PendingNode root = null; 031 private PendingNode tail = null; 032 private final Map<MessageId, PendingNode> map = new HashMap<MessageId, PendingNode>(); 033 034 public PendingNode addMessageFirst(MessageReference message) { 035 PendingNode node = new PendingNode(this, message); 036 if (root == null) { 037 root = node; 038 tail = node; 039 } else { 040 root.linkBefore(node); 041 } 042 this.map.put(message.getMessageId(), node); 043 return node; 044 } 045 046 public PendingNode addMessageLast(MessageReference message) { 047 PendingNode node = new PendingNode(this, message); 048 if (root == null) { 049 root = node; 050 } else { 051 tail.linkAfter(node); 052 } 053 tail = node; 054 this.map.put(message.getMessageId(), node); 055 return node; 056 } 057 058 public void clear() { 059 this.root = null; 060 this.tail = null; 061 this.map.clear(); 062 } 063 064 public boolean isEmpty() { 065 return this.map.isEmpty(); 066 } 067 068 public Iterator<MessageReference> iterator() { 069 return new Iterator<MessageReference>() { 070 private PendingNode current = null; 071 private PendingNode next = root; 072 073 public boolean hasNext() { 074 return next != null; 075 } 076 077 public MessageReference next() { 078 MessageReference result = null; 079 this.current = this.next; 080 result = this.current.getMessage(); 081 this.next = (PendingNode) this.next.getNext(); 082 return result; 083 } 084 085 public void remove() { 086 if (this.current != null && this.current.getMessage() != null) { 087 map.remove(this.current.getMessage().getMessageId()); 088 } 089 removeNode(this.current); 090 } 091 }; 092 } 093 094 public PendingNode remove(MessageReference message) { 095 PendingNode node = null; 096 if (message != null) { 097 node = this.map.remove(message.getMessageId()); 098 removeNode(node); 099 } 100 return node; 101 } 102 103 public int size() { 104 return this.map.size(); 105 } 106 107 void removeNode(PendingNode node) { 108 if (node != null) { 109 map.remove(node.getMessage().getMessageId()); 110 if (root == node) { 111 root = (PendingNode) node.getNext(); 112 } 113 if (tail == node) { 114 tail = (PendingNode) node.getPrevious(); 115 } 116 node.unlink(); 117 } 118 } 119 120 List<PendingNode> getAsList() { 121 List<PendingNode> result = new ArrayList<PendingNode>(size()); 122 PendingNode node = root; 123 while (node != null) { 124 result.add(node); 125 node = (PendingNode) node.getNext(); 126 } 127 return result; 128 } 129 130 @Override 131 public String toString() { 132 return "OrderedPendingList(" + System.identityHashCode(this) + ")"; 133 } 134 135 @Override 136 public boolean contains(MessageReference message) { 137 if(map.values().contains(message)) { 138 return true; 139 } else { 140 return false; 141 } 142 } 143 144 @Override 145 public Collection<MessageReference> values() { 146 List<MessageReference> messageReferences = new ArrayList<MessageReference>(); 147 for(PendingNode pendingNode : map.values()) { 148 messageReferences.add(pendingNode.getMessage()); 149 } 150 return messageReferences; 151 } 152 153 @Override 154 public void addAll(PendingList pendingList) { 155 for(MessageReference messageReference : pendingList) { 156 addMessageLast(messageReference); 157 } 158 } 159}