summaryrefslogtreecommitdiff
path: root/qpid/java/broker-core/src/main/java/org/apache/qpid/server/queue/AssignedConsumerMessageGroupManager.java
blob: efc82c0ab450524847f51a397ae3cf6dcbedb082 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 */
package org.apache.qpid.server.queue;

import org.apache.qpid.server.consumer.Consumer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Iterator;
import java.util.concurrent.ConcurrentHashMap;


public class AssignedConsumerMessageGroupManager<E extends QueueEntryImpl<E,Q,L>, Q extends SimpleAMQQueue<E,Q,L>, L extends SimpleQueueEntryList<E,Q,L>> implements MessageGroupManager<E,Q,L>
{
    private static final Logger _logger = LoggerFactory.getLogger(AssignedConsumerMessageGroupManager.class);


    private final String _groupId;
    private final ConcurrentHashMap<Integer, QueueConsumer> _groupMap = new ConcurrentHashMap<Integer, QueueConsumer>();
    private final int _groupMask;

    public AssignedConsumerMessageGroupManager(final String groupId, final int maxGroups)
    {
        _groupId = groupId;
        _groupMask = pow2(maxGroups)-1;
    }

    private static int pow2(final int i)
    {
        int val = 1;
        while(val < i)
        {
            val<<=1;
        }
        return val;
    }

    public QueueConsumer getAssignedConsumer(final E entry)
    {
        Object groupVal = entry.getMessage().getMessageHeader().getHeader(_groupId);
        return groupVal == null ? null : _groupMap.get(groupVal.hashCode() & _groupMask);
    }

    public boolean acceptMessage(QueueConsumer<?,E,Q,L> sub, E entry)
    {
        return assignMessage(sub, entry) && entry.acquire(sub);
    }

    private boolean assignMessage(QueueConsumer sub, E entry)
    {
        Object groupVal = entry.getMessage().getMessageHeader().getHeader(_groupId);
        if(groupVal == null)
        {
            return true;
        }
        else
        {
            Integer group = groupVal.hashCode() & _groupMask;
            QueueConsumer assignedSub = _groupMap.get(group);
            if(assignedSub == sub)
            {
                return true;
            }
            else
            {
                if(assignedSub == null)
                {
                    if(_logger.isDebugEnabled())
                    {
                        _logger.debug("Assigning group " + groupVal + " to sub " + sub);
                    }
                    assignedSub = _groupMap.putIfAbsent(group, sub);
                    return assignedSub == null || assignedSub == sub;
                }
                else
                {
                    return false;
                }
            }
        }
    }
    
    public E findEarliestAssignedAvailableEntry(QueueConsumer sub)
    {
        EntryFinder visitor = new EntryFinder(sub);
        sub.getQueue().visit(visitor);
        return visitor.getEntry();
    }

    private class EntryFinder implements QueueEntryVisitor<E>
    {
        private E _entry;
        private QueueConsumer _sub;

        public EntryFinder(final QueueConsumer sub)
        {
            _sub = sub;
        }

        public boolean visit(final E entry)
        {
            if(!entry.isAvailable())
            {
                return false;
            }

            Object groupId = entry.getMessage().getMessageHeader().getHeader(_groupId);
            if(groupId == null)
            {
                return false;
            }

            Integer group = groupId.hashCode() & _groupMask;
            Consumer assignedSub = _groupMap.get(group);
            if(assignedSub == _sub)
            {
                _entry = entry;
                return true;
            }
            else
            {
                return false;
            }
        }

        public E getEntry()
        {
            return _entry;
        }
    }

    public void clearAssignments(QueueConsumer sub)
    {
        Iterator<QueueConsumer> subIter = _groupMap.values().iterator();
        while(subIter.hasNext())
        {
            if(subIter.next() == sub)
            {
                subIter.remove();
            }
        }
    }
}