//: Counter5.java
//////////////////////////////////////////////////
// Copyright (c) Bruce Eckel, 1998
// Source code file from the book "Thinking in Java"
// All rights reserved EXCEPT as allowed by the
// following statements: You can freely use this file
// for your own work (personal or commercial),
// including modifications and distribution in
// executable form only. Permission is granted to use
// this file in classroom situations, including its
// use in presentation materials, as long as the book
// "Thinking in Java" is cited as the source.
// Except in classroom situations, you cannot copy
// and distribute this code; instead, the sole
// distribution point is http://www.BruceEckel.com
// (and official mirror sites) where it is
// freely available. You cannot remove this
// copyright and notice. You cannot distribute
// modified versions of the source code in this
// package. You cannot use this file in printed
// media without the express permission of the
// author. Bruce Eckel makes no representation about
// the suitability of this software for any purpose.
// It is provided "as is" without express or implied
// warranty of any kind, including any implied
// warranty of merchantability, fitness for a
// particular purpose or non-infringement. The entire
// risk as to the quality and performance of the
// software is with you. Bruce Eckel and the
// publisher shall not be liable for any damages
// suffered by you or any third party as a result of
// using or distributing software. In no event will
// Bruce Eckel or the publisher 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 software, even if Bruce Eckel
// and the publisher have been advised of the
// possibility of such damages. Should the software
// prove defective, you assume the cost of all
// necessary servicing, repair, or correction. If you
// think you've found an error, please email all
// modified files with clearly commented changes to:
// Bruce@EckelObjects.com. (Please use the same
// address for non-code errors found in the book.)
/////////////////////////////////////////////////
// Adjusting the priorities of threads
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
class Ticker2 extends Thread {
private Button
b = new Button("Toggle"),
incPriority = new Button("up"),
decPriority = new Button("down");
private TextField
t = new TextField(10),
pr = new TextField(3); // Display priority
private int count = 0;
private boolean runFlag = true;
public Ticker2(Container c) {
b.addActionListener(new ToggleL());
incPriority.addActionListener(new UpL());
decPriority.addActionListener(new DownL());
Panel p = new Panel();
p.add(t);
p.add(pr);
p.add(b);
p.add(incPriority);
p.add(decPriority);
c.add(p);
}
class ToggleL implements ActionListener {
public void actionPerformed(ActionEvent e) {
runFlag = !runFlag;
}
}
class UpL implements ActionListener {
public void actionPerformed(ActionEvent e) {
int newPriority = getPriority() + 1;
if(newPriority > Thread.MAX_PRIORITY)
newPriority = Thread.MAX_PRIORITY;
setPriority(newPriority);
}
}
class DownL implements ActionListener {
public void actionPerformed(ActionEvent e) {
int newPriority = getPriority() - 1;
if(newPriority < Thread.MIN_PRIORITY)
newPriority = Thread.MIN_PRIORITY;
setPriority(newPriority);
}
}
public void run() {
while (true) {
if(runFlag) {
t.setText(Integer.toString(count++));
pr.setText(
Integer.toString(getPriority()));
}
yield();
}
}
}
public class Counter5 extends Applet {
private Button
start = new Button("Start"),
upMax = new Button("Inc Max Priority"),
downMax = new Button("Dec Max Priority");
private boolean started = false;
private static final int SIZE = 10;
private Ticker2[] s = new Ticker2[SIZE];
private TextField mp = new TextField(3);
public void init() {
for(int i = 0; i < s.length; i++)
s[i] = new Ticker2(this);
add(new Label("MAX_PRIORITY = "
+ Thread.MAX_PRIORITY));
add(new Label("MIN_PRIORITY = "
+ Thread.MIN_PRIORITY));
add(new Label("Group Max Priority = "));
add(mp);
add(start);
add(upMax); add(downMax);
start.addActionListener(new StartL());
upMax.addActionListener(new UpMaxL());
downMax.addActionListener(new DownMaxL());
showMaxPriority();
// Recursively display parent thread groups:
ThreadGroup parent =
s[0].getThreadGroup().getParent();
while(parent != null) {
add(new Label(
"Parent threadgroup max priority = "
+ parent.getMaxPriority()));
parent = parent.getParent();
}
}
public void showMaxPriority() {
mp.setText(Integer.toString(
s[0].getThreadGroup().getMaxPriority()));
}
class StartL implements ActionListener {
public void actionPerformed(ActionEvent e) {
if(!started) {
started = true;
for(int i = 0; i < s.length; i++)
s[i].start();
}
}
}
class UpMaxL implements ActionListener {
public void actionPerformed(ActionEvent e) {
int maxp =
s[0].getThreadGroup().getMaxPriority();
if(++maxp > Thread.MAX_PRIORITY)
maxp = Thread.MAX_PRIORITY;
s[0].getThreadGroup().setMaxPriority(maxp);
showMaxPriority();
}
}
class DownMaxL implements ActionListener {
public void actionPerformed(ActionEvent e) {
int maxp =
s[0].getThreadGroup().getMaxPriority();
if(--maxp < Thread.MIN_PRIORITY)
maxp = Thread.MIN_PRIORITY;
s[0].getThreadGroup().setMaxPriority(maxp);
showMaxPriority();
}
}
public static void main(String[] args) {
Counter5 applet = new Counter5();
Frame aFrame = new Frame("Counter5");
aFrame.addWindowListener(
new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
aFrame.add(applet, BorderLayout.CENTER);
aFrame.setSize(300, 600);
applet.init();
applet.start();
aFrame.setVisible(true);
}
} ///:~ |