|
1 package org.lobobrowser.util;
2
3 import java.util.*;
4 import java.util.logging.*;
5
6
10 public class SimpleThreadPool {
11 private static final Logger logger = Logger.getLogger(SimpleThreadPool.class.getName());
12 private final LinkedList taskList = new LinkedList();
13 private final Set runningSet = new HashSet();
14 private final int minThreads;
15 private final int maxThreads;
16 private final String  name;
17 private final int idleAliveMillis;
18 private final Object taskMonitor = new Object ();
19 private int numThreads = 0;
20 private int numIdleThreads = 0;
21 private int threadNumber = 0;
22
23 public SimpleThreadPool(String name, int minShrinkToThreads, int maxThreads, int idleAliveMillis) {
24 this.minThreads = minShrinkToThreads;
25 this.maxThreads = maxThreads;
26 this.idleAliveMillis = idleAliveMillis;
27 this.name = name;
28 }
29
30 public void schedule(SimpleThreadPoolTask task) {
31 if(task == null) {
32 throw new IllegalArgumentException ("null task");
33 }
34 Object monitor = this.taskMonitor;
35 synchronized(monitor) {
36 if(this.numIdleThreads == 0) {
37 this.addThreadImpl();
38 }
39 this.taskList.add(task);
40 monitor.notify();
41 }
42 }
43
44 public void cancel(SimpleThreadPoolTask task) {
45 synchronized(this.taskMonitor) {
46 this.taskList.remove(task);
47 }
48 task.cancel();
49 }
50
51 private void addThreadImpl() {
52 if(this.numThreads < this.maxThreads) {
53 Thread t = new Thread (new ThreadRunnable(), this.name + this.threadNumber++);
54 t.setDaemon(true);
55 t.start();
56 this.numThreads++;
57 }
58 }
59
60
63 public void cancelAll() {
64 synchronized(this.taskMonitor) {
65 this.taskList.clear();
66 Iterator i = this.runningSet.iterator();
67 while(i.hasNext()) {
68 ((SimpleThreadPoolTask) i.next()).cancel();
69 }
70 }
71 }
72
73 private class ThreadRunnable implements Runnable {
74 public void run() {
75 Object monitor = taskMonitor;
76 LinkedList tl = taskList;
77 Set rs = runningSet;
78 int iam = idleAliveMillis;
79 SimpleThreadPoolTask task = null;
80 for(;;) {
81 try {
82 synchronized(monitor) {
83 if(task != null) {
84 rs.remove(task);
85 }
86 numIdleThreads++;
87 try {
88 long waitBase = System.currentTimeMillis();
89 INNER:
90 while(tl.isEmpty()) {
91 long maxWait = iam - (System.currentTimeMillis() - waitBase);
92 if(maxWait <= 0) {
93 if(numThreads > minThreads) {
94 numThreads--;
96 return;
97 }
98 else {
99 waitBase = System.currentTimeMillis();
100 continue INNER;
101 }
102 }
103 monitor.wait(maxWait);
104 }
105 } finally {
106 numIdleThreads--;
107 }
108 task = (SimpleThreadPoolTask) taskList.removeFirst();
109 rs.add(task);
110 }
111 Thread currentThread = Thread.currentThread();
112 String baseName = currentThread.getName();
113 try {
114 try {
115 currentThread.setName(baseName + ":" + task.toString());
116 } catch(Throwable thrown) {
117 logger.log(Level.WARNING, "run(): Unable to set task name.", thrown);
118 }
119 try {
120 task.run();
121 } catch(Throwable thrown) {
122 logger.log(Level.SEVERE, "run(): Error in task: " + task + ".", thrown);
123 }
124 } finally {
125 currentThread.setName(baseName);
126 }
127 } catch(Throwable thrown) {
128 logger.log(Level.SEVERE, "run(): Error in thread pool: " + SimpleThreadPool.this.name + ".", thrown);
129 }
130 }
131 }
132 }
133 }
134 |
Popular Tags |
Java API By Example, From Geeks To Geeks.