blob: f696e175877bed9420c7e0e1f35d4f558f290239 (
plain)
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
|
package com.orbekk.same;
import java.util.concurrent.atomic.AtomicBoolean;
/** Updates a variable on-demand.
*/
public class VariableUpdaterTask<T> extends Thread
implements Variable.OnChangeListener<T> {
private Variable<T> variable;
private volatile T newValue;
private AtomicBoolean hasNewValue = new AtomicBoolean(false);
private AtomicBoolean isReady = new AtomicBoolean(true);
public VariableUpdaterTask(Variable<T> variable) {
super("VariableUpdater");
this.variable = variable;
}
public synchronized void set(T newValue) {
this.newValue = newValue;
hasNewValue.set(true);
notifyAll();
}
/** Update the variable once. */
public void performWork() {
boolean shouldDoWork = false;
synchronized(this) {
shouldDoWork = hasNewValue.get() && isReady.get();
hasNewValue.set(false);
isReady.set(false);
}
if (shouldDoWork) {
variable.set(newValue);
}
}
private synchronized void waitFor(AtomicBoolean v) {
if (Thread.interrupted()) {
return;
}
while(!v.get()) {
try {
wait();
} catch (InterruptedException e) {
return;
}
}
}
@Override
public void run() {
variable.addOnChangeListener(this);
while (true) {
waitFor(isReady);
waitFor(hasNewValue);
if (Thread.interrupted()) {
break;
}
performWork();
}
variable.removeOnChangeListener(this);
}
@Override
public synchronized void valueChanged(Variable<T> unused) {
isReady.set(true);
notifyAll();
}
}
|
