Name: el35337 Date: 05/22/98


import java.io.*;
import java.awt.*;
import java.awt.datatransfer.*;
import java.util.*;

/**
 * Test the win32 clipboard. The second setContents only changes the
 * Unicode Text and OEM Text clipboard, not the Text clipboard.
 *
 * @author Senthilvasan Supramaniam
 */


public class ClipTest implements ClipboardOwner{

    public ClipTest() {
    }

    public void lostOwnership(Clipboard clipboard, Transferable contents) {
System.out.println("-->content \""+contents+"\" in clipboard lost ownership...");
    }

    public void setNumber() {
double random = Math.random();
System.out.println("Going to put in clipboard " + random);
Toolkit toolkit = Toolkit.getDefaultToolkit();
Clipboard cb = toolkit.getSystemClipboard();
StringSelection s = new StringSelection(Double.toString(random));
cb.setContents(s, this);
    }

    public void doIt() {
setNumber();
try {
Thread.sleep(1000 * 2);
} catch (InterruptedException e) {
}

setNumber();

    }

    public static void main(String args[]) {

ClipTest t = new ClipTest();
t.doIt();
System.exit(0);
    }
}

If you don't have the sleep it works. Some kind or thread issue here.
(Review ID: 30492)
======================================================================

I've requested more information from the user on how to reproduce this.
 
erik.larsen@Eng 1998-07-13
======================================================================


phil.race@eng 1998-07-21
I could not reproduce the problem with the old test case but included below
is a different, interactive one which does show the problem.

I can reproduce this problem with JDK 1.1.5 and JDK 1.1.6 on my NT 4.0 SP3
system.

I don't understand the different clipboard formats NT supports but
its related to that.

To reproduce
1) compile and execute the test case
2) start each of these 3 standard NT applications :
  - notepad
  - wordpad
  - clipboard viewer

Press the "Copy text to clipboard" button in the test case.
Use the Ctrl-V paste mechanism to copy the clipboard into each of
wordpad and notepad. Also cycle throuh the various formats of the
clipboard viewer.
Notice that they all show the correct text.

Now change the text in the test program and press the "Copy text to clipboard"
button again.
Repeat the paste operation into the notepad and wordpad tools.
notepad gets the change, but NOT wordpad, which pastes the old text again.
Also in the clipboard viewer, only "Unicode text" format reflects the
change.

Repeat this as often as you like and only "Unicode text" and notepad
will see the new clipboard contents.

Again change the text in the test case's text field.
This time use "Ctrl-C to invoke the standard windows functionality to
copy the text to the clipboard.
Now all tools and formats see the change.

This also appears to somehow "reset" something in JDK as the next
"Copy text to clipboard" also works, just like the first one did.
But after that it fails again.

Note that "Swing" text components have to use the clipboard functionality
even for Ctrl-C type copying since they don't get the built-in support
of native peers.
So Swing apps may see this more than AWT apps.


// ClipTest2.java
import java.awt.*;
import java.awt.event.*;
import java.awt.datatransfer.*;

public class ClipTest2 extends Frame
                       implements ClipboardOwner, ActionListener {

    Button setClip;
    TextField text;

    public ClipTest2() {
      add("North", text = new TextField("Here is a text field", 40));
      add("South", setClip = new Button("Copy text to clipboard"));
      setClip.addActionListener(this);
      pack();
      setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
      Toolkit toolkit = Toolkit.getDefaultToolkit();
Clipboard cb = toolkit.getSystemClipboard();
StringSelection s = new StringSelection(text.getText());
      System.out.println("Going to put in clipboard " +text.getText());
cb.setContents(s, this);
    }

    public void lostOwnership(Clipboard clipboard, Transferable contents) {
System.out.println("-->content \""+contents+"\" in clipboard lost ownership...");
    }

    public static void main(String args[]) {

ClipTest2 t = new ClipTest2();
    }
}