/* * Swing version. * XXX: This should probably use a SwingWorker instead of a custom thread. */import java.awt.*;import java.awt.event.*;import javax.swing.*;public class AppletButton extends JApplet                          implements Runnable,                                      ActionListener {    int frameNumber = 1;    String windowClass;    String buttonText;    String windowTitle;    int requestedWidth = 0;    int requestedHeight = 0;    JButton button;    Thread windowThread;    JLabel label;    boolean pleaseShow = false;    boolean shouldInitialize = true;    Class windowClassObject;    public void init() {        //Look up the parameters we need right away.        windowClass = getParameter("WINDOWCLASS");        if (windowClass == null) {            windowClass = "TestWindow";        }        buttonText = getParameter("BUTTONTEXT");        if (buttonText == null) {            buttonText = "Click here to bring up a " + windowClass;        }        //Set up the button and label this applet displays.        button = new JButton(buttonText);        button.addActionListener(this);        label = new JLabel("", JLabel.CENTER);        //Add the button and label to this applet.        Container contentPane = getContentPane();        contentPane.setLayout(new GridLayout(2,0));        contentPane.add(button);        contentPane.add(label);    }    public void start() {        if (windowThread == null) {            windowThread = new Thread(this, "Bringing Up " + windowClass);            windowThread.start();        }    }    public void stop() {        windowThread = null;    }    public synchronized void run() {        Object object = null;        JFrame window = null;        String name = null;                if (shouldInitialize) {            //Look up the rest of the parameters.            windowTitle = getParameter("WINDOWTITLE");            if (windowTitle == null) {                windowTitle = windowClass;            }            String windowWidthString = getParameter("WINDOWWIDTH");            if (windowWidthString != null) {                try {                    requestedWidth = Integer.parseInt(windowWidthString);                } catch (NumberFormatException e) {                    //Use default width.                }            }            String windowHeightString = getParameter("WINDOWHEIGHT");            if (windowHeightString != null) {                try {                    requestedHeight = Integer.parseInt(windowHeightString);                } catch (NumberFormatException e) {                    //Use default height.                }            }             //Make sure the window class exists.            try {                windowClassObject = Class.forName(windowClass);            } catch (Exception e) {                //The specified class isn't anywhere that we can find.                label.setText("Bad parameter: Couldn't find class "                              + windowClass);                button.setEnabled(false);                return;            }                //Create an invisible instance.            window = createWindow(windowTitle);            if (window == null) {                return;            }            shouldInitialize = false;        }        Thread currentThread = Thread.currentThread();        while (currentThread == windowThread) {            //Wait until we're asked to show a window.            while (pleaseShow == false) {                try {                    wait();                } catch (InterruptedException e) {                }            }            //We've been asked to bring up a window.            pleaseShow = false;            //Create another window if necessary.            if (window == null) {                 window = createWindow(windowTitle + ": "                                       + ++frameNumber);            }             window.setVisible(true);            label.setText("");            window = null;        } //end thread loop    }    private JFrame createWindow(String title) {        Object object = null;        JFrame window = null;        //Instantiate the window class.        try {            object = windowClassObject.newInstance();         } catch (Exception e) {            label.setText("Bad parameter: Can't instantiate "                          + windowClassObject);            button.setEnabled(false);            return null;        }        //Make sure it's a frame.        try {            window = (JFrame)object;        } catch (Exception e) {            label.setText("Bad parameter: "                          + windowClassObject +                          " isn't a JFrame subclass.");            button.setEnabled(false);            return null;        }        window.setTitle(title);        //Set its size.        window.pack();        if ((requestedWidth > 0)           | (requestedHeight > 0)) {            window.setSize(Math.max(requestedWidth,                                    window.getSize().width),                           Math.max(requestedHeight,                                    window.getSize().height));        }        return window;    }                    /* Signal the window thread to build a window. */    public synchronized void actionPerformed(ActionEvent event) {        label.setText("Please wait while the window comes up...");        pleaseShow = true;        notify();    }}class TestWindow extends JFrame {    public TestWindow() {        setDefaultCloseOperation(DISPOSE_ON_CLOSE);    }}