Source code: org/altara/util/Worker.java
1 /* Altara Utility Classes
2 Copyright (c) 2001,2002 Brian H. Trammell
3
4 This library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 This library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with this library; if not, it is available at
16 http://www.gnu.org/copyleft/lesser.html, or by writing to the
17 Free Software Foundation, Inc., 59 Temple Place, Suite 330,
18 Boston, MA 02111-1307 USA
19 */
20
21 package org.altara.util;
22
23 public abstract class Worker extends Thread {
24
25 private boolean running;
26 private boolean awake;
27
28 protected Worker() {
29 super();
30 }
31
32 protected Worker(String name) {
33 super(name);
34 }
35
36 // thread control methods
37
38 public void start() {
39 this.running = true;
40 this.awake = true;
41 super.start();
42 }
43
44 public void startAsleep() {
45 this.running = true;
46 this.awake = false;
47 super.start();
48 }
49
50 public synchronized void lull() {
51 this.awake = false;
52 }
53
54 public synchronized void wake() {
55 this.awake = true;
56 this.notify();
57 }
58
59 public synchronized void kill() {
60 this.awake = true;
61 this.running = false;
62 this.interrupt();
63 }
64
65 // thread body
66
67 public final void run() {
68 while (running) {
69 // Check to see if I should sleep
70 if (!awake) {
71 synchronized(this) {
72 try {
73 this.wait();
74 } catch (InterruptedException ex) {
75 // We must skip over our action, since
76 // this interrupt may be a kill() interrupt.
77 continue;
78 }
79 }
80 }
81
82 // this can block too
83 try {
84 work();
85 } catch (Exception ex) {
86 workException(ex);
87 }
88 }
89 workExit();
90 }
91
92 protected abstract void work() throws Exception;
93
94 protected void workException(Exception ex) {
95 // do nothing by default
96 }
97
98 protected void workExit() {
99 // do nothing by default
100 }
101 }