1 /***
2 * Copyright 2003-2010 Terracotta, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package net.sf.ehcache.writer.writebehind;
18
19 import net.sf.ehcache.CacheEntry;
20 import net.sf.ehcache.CacheException;
21 import net.sf.ehcache.Element;
22 import net.sf.ehcache.config.CacheConfiguration;
23 import net.sf.ehcache.config.CacheWriterConfiguration;
24 import net.sf.ehcache.writer.CacheWriter;
25
26 import java.util.ArrayList;
27 import java.util.List;
28 import java.util.concurrent.locks.ReentrantReadWriteLock;
29
30 /***
31 * @author Alex Snaps
32 */
33 public class WriteBehindQueueManager implements WriteBehind {
34
35 private final ReentrantReadWriteLock rwLock = new ReentrantReadWriteLock();
36 private final ReentrantReadWriteLock.ReadLock readLock = rwLock.readLock();
37 private final ReentrantReadWriteLock.WriteLock writeLock = rwLock.writeLock();
38
39 private List<WriteBehindQueue> queues = new ArrayList<WriteBehindQueue>();
40
41 /***
42 * Create a new write behind queue manager. Which in turn will create as many queues as
43 * required by the {@link net.sf.ehcache.config.CacheWriterConfiguration#getWriteBehindConcurrency}
44 *
45 * @param config the configuration for the queue
46 */
47 public WriteBehindQueueManager(CacheConfiguration config) {
48 CacheWriterConfiguration cacheWriterConfiguration = config.getCacheWriterConfiguration();
49 int writeBehindConcurrency = cacheWriterConfiguration.getWriteBehindConcurrency();
50 for (int i = 0; i < writeBehindConcurrency; i++) {
51 this.queues.add(new WriteBehindQueue(config));
52 }
53 }
54
55 /***
56 * {@inheritDoc}
57 */
58 public void start(final CacheWriter writer) throws CacheException {
59 writeLock.lock();
60 try {
61 for (WriteBehindQueue queue : queues) {
62 queue.start(writer);
63 }
64 } finally {
65 writeLock.unlock();
66 }
67 }
68
69 /***
70 * {@inheritDoc}
71 */
72 public void write(final Element element) {
73 readLock.lock();
74 try {
75 getQueue(element.getKey()).write(element);
76 } finally {
77 readLock.unlock();
78 }
79 }
80
81 private WriteBehindQueue getQueue(final Object key) {
82 return queues.get(Math.abs(key.hashCode() % queues.size()));
83 }
84
85 /***
86 * {@inheritDoc}
87 */
88 public void delete(final CacheEntry entry) {
89 readLock.lock();
90 try {
91 getQueue(entry.getKey()).delete(entry);
92 } finally {
93 readLock.unlock();
94 }
95 }
96
97 /***
98 * {@inheritDoc}
99 */
100 public void setOperationsFilter(final OperationsFilter filter) {
101 readLock.lock();
102 try {
103 for (WriteBehindQueue queue : queues) {
104 queue.setOperationsFilter(filter);
105 }
106 } finally {
107 readLock.unlock();
108 }
109 }
110
111 /***
112 * {@inheritDoc}
113 */
114 public void stop() throws CacheException {
115 writeLock.lock();
116 try {
117 for (WriteBehindQueue queue : queues) {
118 queue.stop();
119 }
120 } finally {
121 writeLock.unlock();
122 }
123 }
124
125 /***
126 * {@inheritDoc}
127 */
128 public long getQueueSize() {
129 int size = 0;
130 readLock.lock();
131 try {
132 for (WriteBehindQueue queue : queues) {
133 size += queue.getQueueSize();
134 }
135 } finally {
136 readLock.unlock();
137 }
138 return size;
139 }
140 }