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.cursors;
018
019 import java.util.ArrayList;
020 import java.util.Collection;
021 import java.util.HashMap;
022 import java.util.Iterator;
023 import java.util.List;
024 import java.util.Map;
025
026 import org.apache.activemq.broker.region.MessageReference;
027 import org.apache.activemq.command.MessageId;
028
029 public class OrderedPendingList implements PendingList {
030
031 private PendingNode root = null;
032 private PendingNode tail = null;
033 private final Map<MessageId, PendingNode> map = new HashMap<MessageId, PendingNode>();
034
035 public PendingNode addMessageFirst(MessageReference message) {
036 PendingNode node = new PendingNode(this, message);
037 if (root == null) {
038 root = node;
039 tail = node;
040 } else {
041 root.linkBefore(node);
042 root = node;
043 }
044 this.map.put(message.getMessageId(), node);
045 return node;
046 }
047
048 public PendingNode addMessageLast(MessageReference message) {
049 PendingNode node = new PendingNode(this, message);
050 if (root == null) {
051 root = node;
052 } else {
053 tail.linkAfter(node);
054 }
055 tail = node;
056 this.map.put(message.getMessageId(), node);
057 return node;
058 }
059
060 public void clear() {
061 this.root = null;
062 this.tail = null;
063 this.map.clear();
064 }
065
066 public boolean isEmpty() {
067 return this.map.isEmpty();
068 }
069
070 public Iterator<MessageReference> iterator() {
071 return new Iterator<MessageReference>() {
072 private PendingNode current = null;
073 private PendingNode next = root;
074
075 public boolean hasNext() {
076 return next != null;
077 }
078
079 public MessageReference next() {
080 MessageReference result = null;
081 this.current = this.next;
082 result = this.current.getMessage();
083 this.next = (PendingNode) this.next.getNext();
084 return result;
085 }
086
087 public void remove() {
088 if (this.current != null && this.current.getMessage() != null) {
089 map.remove(this.current.getMessage().getMessageId());
090 }
091 removeNode(this.current);
092 }
093 };
094 }
095
096 public PendingNode remove(MessageReference message) {
097 PendingNode node = null;
098 if (message != null) {
099 node = this.map.remove(message.getMessageId());
100 removeNode(node);
101 }
102 return node;
103 }
104
105 public int size() {
106 return this.map.size();
107 }
108
109 void removeNode(PendingNode node) {
110 if (node != null) {
111 map.remove(node.getMessage().getMessageId());
112 if (root == node) {
113 root = (PendingNode) node.getNext();
114 }
115 if (tail == node) {
116 tail = (PendingNode) node.getPrevious();
117 }
118 node.unlink();
119 }
120 }
121
122 List<PendingNode> getAsList() {
123 List<PendingNode> result = new ArrayList<PendingNode>(size());
124 PendingNode node = root;
125 while (node != null) {
126 result.add(node);
127 node = (PendingNode) node.getNext();
128 }
129 return result;
130 }
131
132 @Override
133 public String toString() {
134 return "OrderedPendingList(" + System.identityHashCode(this) + ")";
135 }
136
137 @Override
138 public boolean contains(MessageReference message) {
139 if (message != null) {
140 for (PendingNode value : map.values()) {
141 if (value.getMessage().equals(message)) {
142 return true;
143 }
144 }
145 }
146 return false;
147 }
148
149 @Override
150 public Collection<MessageReference> values() {
151 List<MessageReference> messageReferences = new ArrayList<MessageReference>();
152 for(PendingNode pendingNode : map.values()) {
153 messageReferences.add(pendingNode.getMessage());
154 }
155 return messageReferences;
156 }
157
158 @Override
159 public void addAll(PendingList pendingList) {
160 if (pendingList != null) {
161 for(MessageReference messageReference : pendingList) {
162 addMessageLast(messageReference);
163 }
164 }
165 }
166 }