в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== 14. extends generic SwingWorker ==



<source lang="java">
/*
* Copyright (c) 1995 - 2008 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:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions 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 nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.List;
import java.util.Random;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
import javax.swing.border.Border;
public class Flipper extends JFrame implements ActionListener {
private final GridBagConstraints constraints;
private final JTextField headsText, totalText, devText;
private final Border border = BorderFactory.createLoweredBevelBorder();
private final JButton startButton, stopButton;
private FlipTask flipTask;
private JTextField makeText() {
JTextField t = new JTextField(20);
t.setEditable(false);
t.setHorizontalAlignment(JTextField.RIGHT);
t.setBorder(border);
getContentPane().add(t, constraints);
return t;
}
private JButton makeButton(String caption) {
JButton b = new JButton(caption);
b.setActionCommand(caption);
b.addActionListener(this);
getContentPane().add(b, constraints);
return b;
}
public Flipper() {
super("Flipper");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Make text boxes
getContentPane().setLayout(new GridBagLayout());
constraints = new GridBagConstraints();
constraints.insets = new Insets(3, 10, 3, 10);
headsText = makeText();
totalText = makeText();
devText = makeText();
// Make buttons
startButton = makeButton("Start");
stopButton = makeButton("Stop");
stopButton.setEnabled(false);
// Display the window.
pack();
setVisible(true);
}
private static class FlipPair {
private final long heads, total;
FlipPair(long heads, long total) {
this.heads = heads;
this.total = total;
}
}
private class FlipTask extends SwingWorker<Void, FlipPair> {
@Override
protected Void doInBackground() {
long heads = 0;
long total = 0;
Random random = new Random();
while (!isCancelled()) {
total++;
if (random.nextBoolean()) {
heads++;
}
publish(new FlipPair(heads, total));
}
return null;
}
@Override
protected void process(List<FlipPair> pairs) {
FlipPair pair = pairs.get(pairs.size() - 1);
headsText.setText(String.format("%d", pair.heads));
totalText.setText(String.format("%d", pair.total));
devText.setText(String.format("%.10g", ((double) pair.heads)
/ ((double) pair.total) - 0.5));
}
}
public void actionPerformed(ActionEvent e) {
if ("Start" == e.getActionCommand()) {
startButton.setEnabled(false);
stopButton.setEnabled(true);
(flipTask = new FlipTask()).execute();
} else if ("Stop" == e.getActionCommand()) {
startButton.setEnabled(true);
stopButton.setEnabled(false);
flipTask.cancel(true);
flipTask = null;
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Flipper();
}
});
}
}</source>



== 14. Progress Monitor and Swingworker ==



<source lang="java">
/*
* Copyright (c) 1995 - 2008 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:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions 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 nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
import java.awt.BorderLayout;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Random;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.ProgressMonitor;
import javax.swing.SwingWorker;
public class ProgressMonitorDemo extends JPanel implements ActionListener,
PropertyChangeListener {
private ProgressMonitor progressMonitor;
private JButton startButton;
private JTextArea taskOutput;
private Task task;
class Task extends SwingWorker<Void, Void> {
@Override
public Void doInBackground() {
Random random = new Random();
int progress = 0;
setProgress(0);
try {
Thread.sleep(1000);
while (progress < 100 && !isCancelled()) {
// Sleep for up to one second.
Thread.sleep(random.nextInt(1000));
// Make random progress.
progress += random.nextInt(10);
setProgress(Math.min(progress, 100));
}
} catch (InterruptedException ignore) {
}
return null;
}
@Override
public void done() {
Toolkit.getDefaultToolkit().beep();
startButton.setEnabled(true);
progressMonitor.setProgress(0);
}
}
public ProgressMonitorDemo() {
super(new BorderLayout());
// Create the demo"s UI.
startButton = new JButton("Start");
startButton.setActionCommand("start");
startButton.addActionListener(this);
taskOutput = new JTextArea(5, 20);
taskOutput.setMargin(new Insets(5, 5, 5, 5));
taskOutput.setEditable(false);
add(startButton, BorderLayout.PAGE_START);
add(new JScrollPane(taskOutput), BorderLayout.CENTER);
setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
}
/**
* Invoked when the user presses the start button.
*/
public void actionPerformed(ActionEvent evt) {
progressMonitor = new ProgressMonitor(ProgressMonitorDemo.this,
"Running a Long Task", "", 0, 100);
progressMonitor.setProgress(0);
task = new Task();
task.addPropertyChangeListener(this);
task.execute();
startButton.setEnabled(false);
}
/**
* Invoked when task"s progress property changes.
*/
public void propertyChange(PropertyChangeEvent evt) {
if ("progress" == evt.getPropertyName()) {
int progress = (Integer) evt.getNewValue();
progressMonitor.setProgress(progress);
String message = String.format("Completed %d%%.\n", progress);
progressMonitor.setNote(message);
taskOutput.append(message);
if (progressMonitor.isCanceled() || task.isDone()) {
Toolkit.getDefaultToolkit().beep();
if (progressMonitor.isCanceled()) {
task.cancel(true);
taskOutput.append("Task canceled.\n");
} else {
taskOutput.append("Task completed.\n");
}
startButton.setEnabled(true);
}
}
}
/**
* Create the GUI and show it. For thread safety, this method should be
* invoked from the event-dispatching thread.
*/
private static void createAndShowGUI() {
// Create and set up the window.
JFrame frame = new JFrame("ProgressMonitorDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create and set up the content pane.
JComponent newContentPane = new ProgressMonitorDemo();
newContentPane.setOpaque(true); // content panes must be opaque
frame.setContentPane(newContentPane);
// Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
// Schedule a job for the event-dispatching thread:
// creating and showing this application"s GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}</source>



== 14. SwingWorker in Java 6 ==



<source lang="java">
import java.awt.LayoutManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.List;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingWorker;
public class Main{
public static void main(String[] args) {
final JProgressBar progressBar = new JProgressBar(0, 10);
final CounterTask task = new CounterTask();
task.addPropertyChangeListener(new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
if ("progress".equals(evt.getPropertyName())) {
progressBar.setValue((Integer) evt.getNewValue());
}
}
});
JButton startButton = new JButton("Start");
startButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
task.execute();
}
});
JButton cancelButton = new JButton("Cancel");
cancelButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
task.cancel(true);
}
});
JPanel buttonPanel = new JPanel();
buttonPanel.add(startButton);
buttonPanel.add(cancelButton);
JPanel cp = new JPanel();
LayoutManager layout = new BoxLayout(cp, BoxLayout.Y_AXIS);
cp.setLayout(layout);
cp.add(buttonPanel);
cp.add(progressBar);
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(cp);
frame.pack();
frame.setVisible(true);
}
}
class CounterTask extends SwingWorker<Integer, Integer> {
int DELAY = 1000;
@Override
protected Integer doInBackground() throws Exception {
int i = 0;
int count = 10;
while (!isCancelled() && i < count) {
i++;
publish(new Integer[] { i });
setProgress(count * i / count);
Thread.sleep(DELAY);
}
return count;
}
protected void process(List<Integer> chunks) {
System.out.println(chunks);
}
@Override
protected void done() {
if (isCancelled())
System.out.println("Cancelled !");
else
System.out.println("Done !");
}
}</source>



== 14. Use SwingWorker to perform background tasks ==



<source lang="java">
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.SwingWorker;
public class Main extends JFrame {
public Main() {
this.setLayout(new FlowLayout());
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton processButton = new JButton("Start");
JButton helloButton = new JButton("Hello");
processButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
MyTask process = new MyTask();
try {
process.execute();
} catch (Exception e) {
e.printStackTrace();
}
}
});
helloButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(null, "Hello There");
}
});
this.getContentPane().add(processButton);
this.getContentPane().add(helloButton);
this.pack();
setVisible(true);
}
public static void main(String[] args) {
new Main();
}
}
class MyTask extends SwingWorker {
protected Object doInBackground() throws Exception {
Integer result = new Integer(0);
for (int i = 0; i < 10; i++) {
result += i * 10;
try {
Thread.sleep(5000);
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}
}</source>

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