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;
025
026import org.apache.activemq.broker.region.MessageReference;
027import org.apache.activemq.command.MessageId;
028
029public class PrioritizedPendingList implements PendingList {
030
031    private static final Integer MAX_PRIORITY = 10;
032    private final OrderedPendingList[] lists = new OrderedPendingList[MAX_PRIORITY];
033    private final Map<MessageId, PendingNode> map = new HashMap<MessageId, PendingNode>();
034
035    public PrioritizedPendingList() {
036        for (int i = 0; i < MAX_PRIORITY; i++) {
037            this.lists[i] = new OrderedPendingList();
038        }
039    }
040
041    public PendingNode addMessageFirst(MessageReference message) {
042        PendingNode node = getList(message).addMessageFirst(message);
043        this.map.put(message.getMessageId(), node);
044        return node;
045    }
046
047    public PendingNode addMessageLast(MessageReference message) {
048        PendingNode node = getList(message).addMessageLast(message);
049        this.map.put(message.getMessageId(), node);
050        return node;
051    }
052
053    public void clear() {
054        for (int i = 0; i < MAX_PRIORITY; i++) {
055            this.lists[i].clear();
056        }
057        this.map.clear();
058    }
059
060    public boolean isEmpty() {
061        return this.map.isEmpty();
062    }
063
064    public Iterator<MessageReference> iterator() {
065        return new PrioritizedPendingListIterator();
066    }
067
068    public PendingNode remove(MessageReference message) {
069        PendingNode node = null;
070        if (message != null) {
071            node = this.map.remove(message.getMessageId());
072            if (node != null) {
073                node.getList().removeNode(node);
074            }
075        }
076        return node;
077    }
078
079    public int size() {
080        return this.map.size();
081    }
082
083    @Override
084    public String toString() {
085        return "PrioritizedPendingList(" + System.identityHashCode(this) + ")";
086    }
087
088    protected int getPriority(MessageReference message) {
089        int priority = javax.jms.Message.DEFAULT_PRIORITY;
090        if (message.getMessageId() != null) {
091            priority = Math.max(message.getMessage().getPriority(), 0);
092            priority = Math.min(priority, 9);
093        }
094        return priority;
095    }
096
097    protected OrderedPendingList getList(MessageReference msg) {
098        return lists[getPriority(msg)];
099    }
100
101    private class PrioritizedPendingListIterator implements Iterator<MessageReference> {
102        private int index = 0;
103        private int currentIndex = 0;
104        List<PendingNode> list = new ArrayList<PendingNode>(size());
105
106        PrioritizedPendingListIterator() {
107            for (int i = MAX_PRIORITY - 1; i >= 0; i--) {
108                OrderedPendingList orderedPendingList = lists[i];
109                if (!orderedPendingList.isEmpty()) {
110                    list.addAll(orderedPendingList.getAsList());
111                }
112            }
113        }
114        public boolean hasNext() {
115            return list.size() > index;
116        }
117
118        public MessageReference next() {
119            PendingNode node = list.get(this.index);
120            this.currentIndex = this.index;
121            this.index++;
122            return node.getMessage();
123        }
124
125        public void remove() {
126            PendingNode node = list.get(this.currentIndex);
127            if (node != null) {
128                map.remove(node.getMessage().getMessageId());
129                node.getList().removeNode(node);
130            }
131        }
132    }
133
134    @Override
135    public boolean contains(MessageReference message) {
136        if (map.values().contains(message)) {
137            return true;
138        }
139
140        return false;
141    }
142
143    @Override
144    public Collection<MessageReference> values() {
145        List<MessageReference> messageReferences = new ArrayList<MessageReference>();
146        for (PendingNode pendingNode : map.values()) {
147            messageReferences.add(pendingNode.getMessage());
148        }
149        return messageReferences;
150    }
151
152    @Override
153    public void addAll(PendingList pendingList) {
154        for(MessageReference messageReference : pendingList) {
155            addMessageLast(messageReference);
156        }
157    }
158
159}