Name: joT67522 Date: 10/27/97


/*
 * java.awt.Dialog blocking bug
 * Jason Mathews
 * Fri, Oct 24, 06:11:17 PM
 *
 * Problem: Modal dialogs do not block fast enough allowing for multiple
 * modal dialog instances to be created before the block is enabled.
 *
 * Clicking on the "Create Modal Dialog..." button on applet/frame several
 * times in rapid succession brings up multiple dialog windows. It appears
 * that there's a race condition of whether the first modal dialog
 * invokes the modal block or the subsequent Button events are processed by
 * the applet's event handler. The create dialog button event is handled
 * before the first modal dialog instance invokes the modal block, hence
 * multiple dialogs are created when you only want one.
 *
 * Works as expected under JDK 1.0.2 where blocking
 * is immediate. However, the modal block in
 * JDK 1.1.3 is slow to respond to the lock.
 *
 * Same behavior on SGI/IRIX 5.3 and DEC Alpha OSF.
 */

import java.awt.*;
import java.applet.*;

class TestDialog extends Dialog {

  public TestDialog(Frame parent, String title) {
    super(parent, title, true);
    System.err.println("create: " + title);
    setLayout(new BorderLayout(15,15));
    // do something that takes a little time
    for (int i=1; i < 100000; i++)
      new Integer(i);
    add("Center", new Label("This a test", Label.CENTER));
    add("South", new Button("Ok"));
    resize(200,80);
    System.err.println("show: " + title);
    show();
  }

  public boolean action (Event e, Object arg) {
    if (e.target instanceof Button) {
      hide();
      dispose();
      return true;
    }
    return false;
  }

}

------- BugDialog.java ----------


import java.awt.*;
import java.applet.*;

public class BugDialog extends Applet {

  int count = 1;
  boolean workaround = false;

  public BugDialog() {
    add(new Button("Create Modal Dialog..."));
    add(new Checkbox("Enable workaround"));
    resize(100,100);
  }

  public boolean action(Event e, Object o) {
    if (e.target instanceof Button) {
      Container parent = getParent();
      while (parent != null && ! (parent instanceof Frame) )
parent = parent.getParent();
      if (workaround) disable();
      new TestDialog((Frame)parent, "Modal Dialog " + count++);
      if (workaround) enable();
    } else if (e.target instanceof Checkbox) {
      workaround = ((Checkbox)e.target).getState();
      System.err.println("workaround " + workaround);
    } else {
      return false;
    }
      return true;

  }
  
  public static void main (String args[])
  {
    Frame f = new Frame("BugDialog");
    BugDialog d = new BugDialog();
    d.init();
    d.start();
    f.add("Center", d);
    f.pack();
    f.show();
  }

}
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