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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
/*
* Copyright (c) 2009 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* - Redistribution of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
* INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
* MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
* ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
* DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
* DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
* ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
* SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed or intended for use
* in the design, construction, operation or maintenance of any nuclear
* facility.
*/
package demos.newt.util;
import java.util.*;
public class TaskManager {
private ThreadGroup threadGroup;
private volatile boolean shouldStop = false;
private TaskWorker taskWorker = null;
private Object taskWorkerLock = new Object();
private ArrayList tasks = new ArrayList();
private String name;
public TaskManager(String name) {
threadGroup = new ThreadGroup(name);
this.name=name;
}
public String getName() { return name; }
public ThreadGroup getThreadGroup() { return threadGroup; }
public void start() {
start(false);
}
/**
* @param externalStimuli true indicates that another thread stimulates,
* ie. calls this TaskManager's run() loop method.
* Hence no own thread is started in this case.
*
* @return The started Runnable, which handles the run-loop.
* Usefull in combination with externalStimuli=true,
* so an external stimuli can call it.
*/
public Runnable start(boolean externalStimuli) {
synchronized(taskWorkerLock) {
if(null==taskWorker) {
taskWorker = new TaskWorker(name);
}
if(!taskWorker.isRunning()) {
shouldStop = false;
taskWorker.start(externalStimuli);
}
taskWorkerLock.notifyAll();
}
return taskWorker;
}
public void stop() {
synchronized(taskWorkerLock) {
if(null!=taskWorker && taskWorker.isRunning()) {
shouldStop = true;
}
taskWorkerLock.notifyAll();
}
}
public void addTask(Runnable task) {
if(task == null) {
return;
}
synchronized(taskWorkerLock) {
tasks.add(task);
taskWorkerLock.notifyAll();
}
}
public void removeTask(Runnable task) {
if (task == null) {
return;
}
synchronized(taskWorkerLock) {
tasks.remove(task);
taskWorkerLock.notifyAll();
}
}
public Runnable[] getTasks() {
Runnable[] res;
synchronized(taskWorkerLock) {
res = (Runnable[]) tasks.toArray();
}
return res;
}
public void waitOnWorker() {
synchronized(taskWorkerLock) {
if(null!=taskWorker && taskWorker.isRunning()) {
try {
taskWorkerLock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public void waitUntilStopped() {
synchronized(taskWorkerLock) {
while(null!=taskWorker && taskWorker.isRunning()) {
try {
taskWorkerLock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
class TaskWorker extends Thread {
volatile boolean isRunning = false;
volatile boolean externalStimuli = false;
public TaskWorker(String name) {
super(threadGroup, name);
}
public synchronized boolean isRunning() {
return isRunning;
}
public void start(boolean externalStimuli) throws IllegalThreadStateException {
synchronized(this) {
this.externalStimuli = externalStimuli;
isRunning = true;
}
if(!externalStimuli) {
super.start();
}
}
public void run() {
while(!shouldStop) {
try {
// prolog - lock stuff you may wanne do ..
ArrayList clonedTasks;
// wait for something todo ..
synchronized(taskWorkerLock) {
while(!shouldStop && tasks.size()==0) {
try {
taskWorkerLock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
// make a safe clone of the list
// since it may change while working on it
clonedTasks = (ArrayList) tasks.clone();
}
// do it for all tasks
for(Iterator i = clonedTasks.iterator(); i.hasNext(); ) {
Runnable task = (Runnable) i.next();
task.run();
}
} catch (Throwable t) {
// handle errors ..
t.printStackTrace();
} finally {
// epilog - unlock locked stuff
}
if(externalStimuli) break; // no loop if called by external stimuli
}
synchronized(this) {
isRunning = !shouldStop;
}
if(!isRunning) {
synchronized(taskWorkerLock) {
taskWorkerLock.notifyAll();
}
}
}
}
}
|
