Fix eclipse/checkstyle warnings
[yangtools.git] / common / util / src / main / java / org / opendaylight / yangtools / util / concurrent / FastThreadPoolExecutor.java
1 /*
2  * Copyright (c) 2014 Brocade Communications Systems, Inc. and others.  All rights reserved.
3  *
4  * This program and the accompanying materials are made available under the
5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6  * and is available at http://www.eclipse.org/legal/epl-v10.html
7  */
8
9 package org.opendaylight.yangtools.util.concurrent;
10
11 import com.google.common.base.MoreObjects;
12 import com.google.common.base.MoreObjects.ToStringHelper;
13 import com.google.common.util.concurrent.ThreadFactoryBuilder;
14 import java.util.concurrent.ThreadPoolExecutor;
15 import java.util.concurrent.TimeUnit;
16
17 /**
18  * A ThreadPoolExecutor with a specified bounded queue capacity that favors creating new threads
19  * over queuing, as the former is faster.
20  *
21  * <p>See {@link SpecialExecutors#newBoundedFastThreadPool} for more details.
22  *
23  * @author Thomas Pantelis
24  */
25 public class FastThreadPoolExecutor extends ThreadPoolExecutor {
26
27     private static final long DEFAULT_IDLE_TIMEOUT_IN_SEC = 15L;
28
29     private final String threadPrefix;
30     private final int maximumQueueSize;
31
32     /**
33      * Constructs a FastThreadPoolExecutor instance.
34      *
35      * @param maximumPoolSize
36      *            the maximum number of threads to allow in the pool. Threads will terminate after
37      *            being idle for 15 seconds.
38      * @param maximumQueueSize
39      *            the capacity of the queue.
40      * @param threadPrefix
41      *            the name prefix for threads created by this executor.
42      */
43     public FastThreadPoolExecutor(final int maximumPoolSize, final int maximumQueueSize, final String threadPrefix) {
44         this(maximumPoolSize, maximumQueueSize, DEFAULT_IDLE_TIMEOUT_IN_SEC, TimeUnit.SECONDS,
45               threadPrefix);
46     }
47
48     /**
49      * Constructs a FastThreadPoolExecutor instance.
50      *
51      * @param maximumPoolSize
52      *            the maximum number of threads to allow in the pool.
53      * @param maximumQueueSize
54      *            the capacity of the queue.
55      * @param keepAliveTime
56      *            the maximum time that idle threads will wait for new tasks before terminating.
57      * @param unit
58      *            the time unit for the keepAliveTime argument
59      * @param threadPrefix
60      *            the name prefix for threads created by this executor.
61      */
62     public FastThreadPoolExecutor(final int maximumPoolSize, final int maximumQueueSize, final long keepAliveTime,
63             final TimeUnit unit, final String threadPrefix) {
64         // We use all core threads (the first 2 parameters below equal) so, when a task is submitted,
65         // if the thread limit hasn't been reached, a new thread will be spawned to execute
66         // the task even if there is an existing idle thread in the pool. This is faster than
67         // handing the task to an existing idle thread via the queue. Once the thread limit is
68         // reached, subsequent tasks will be queued. If the queue is full, tasks will be rejected.
69
70         super(maximumPoolSize, maximumPoolSize, keepAliveTime, unit,
71                 new TrackingLinkedBlockingQueue<>(maximumQueueSize));
72
73         this.threadPrefix = threadPrefix;
74         this.maximumQueueSize = maximumQueueSize;
75
76         setThreadFactory(new ThreadFactoryBuilder().setDaemon(true)
77                                                  .setNameFormat(threadPrefix + "-%d").build());
78
79         if (keepAliveTime > 0) {
80             // Need to specifically configure core threads to timeout.
81             allowCoreThreadTimeOut(true);
82         }
83
84         setRejectedExecutionHandler(CountingRejectedExecutionHandler.newAbortPolicy());
85     }
86
87     public long getLargestQueueSize() {
88         return ((TrackingLinkedBlockingQueue<?>)getQueue()).getLargestQueueSize();
89     }
90
91     protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
92         return toStringHelper;
93     }
94
95     @Override
96     public final String toString() {
97         return addToStringAttributes(MoreObjects.toStringHelper(this)
98                 .add("Thread Prefix", threadPrefix)
99                 .add("Current Thread Pool Size", getPoolSize())
100                 .add("Largest Thread Pool Size", getLargestPoolSize())
101                 .add("Max Thread Pool Size", getMaximumPoolSize())
102                 .add("Current Queue Size", getQueue().size())
103                 .add("Largest Queue Size", getLargestQueueSize())
104                 .add("Max Queue Size", maximumQueueSize)
105                 .add("Active Thread Count", getActiveCount())
106                 .add("Completed Task Count", getCompletedTaskCount())
107                 .add("Total Task Count", getTaskCount())).toString();
108     }
109 }