1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. 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, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package org.jboss.netty.util.internal;
17
18 import java.util.concurrent.BlockingQueue;
19
20 import org.jboss.netty.logging.InternalLogger;
21 import org.jboss.netty.logging.InternalLoggerFactory;
22
23 /**
24 * This factory should be used to create the "optimal" {@link BlockingQueue}
25 * instance for the running JVM.
26 */
27 @Deprecated
28 public final class QueueFactory {
29
30 private static final boolean useUnsafe = DetectionUtil.hasUnsafe();
31 private static final InternalLogger LOGGER = InternalLoggerFactory.getInstance(QueueFactory.class);
32
33 private QueueFactory() {
34 // only use static methods!
35 }
36
37
38 /**
39 * Create a new unbound {@link BlockingQueue}
40 *
41 * @param itemClass the {@link Class} type which will be used as {@link BlockingQueue} items
42 * @return queue the {@link BlockingQueue} implementation
43 */
44 public static <T> BlockingQueue<T> createQueue(Class<T> itemClass) {
45 // if we run in java >=7 its the best to just use the LinkedTransferQueue which
46 // comes with java bundled. See #273
47 if (DetectionUtil.javaVersion() >= 7) {
48 return new java.util.concurrent.LinkedTransferQueue<T>();
49 }
50
51 try {
52 if (useUnsafe) {
53 return new LinkedTransferQueue<T>();
54 }
55 } catch (Throwable t) {
56 // For whatever reason an exception was thrown while loading the LinkedTransferQueue
57 //
58 // This mostly happens because of a custom classloader or security policy that did not
59 // allow us to access the com.sun.Unmisc class. So just log it and fallback to the old
60 // LegacyLinkedTransferQueue that works in all cases
61 if (LOGGER.isDebugEnabled()) {
62 LOGGER.debug("Unable to instance LinkedTransferQueue, fallback to LegacyLinkedTransferQueue", t);
63 }
64 }
65
66 return new LegacyLinkedTransferQueue<T>();
67
68 }
69 }