Name: dsC58869 Date: 09/03/97



java.beans.VetoableChangeSupport constructor() works wrong if called with null parameter.
It creates an object with invalid state:
firePropertyChange() call causes IllegalArgumentException

This constructor shoud probably throw an IllegalArgumentException
(as java.util.EventObject does) or a NullPointerException.

java.beans.PropertyChangeSupport has the same problem.

==== Here is the test demonstrating the bug ====

import java.beans.*;

public class TestVCS {
  
  public static void main (String args[]) {
        System.out.println("passing a null source");
        NewVetoableChangeSupport changes = new NewVetoableChangeSupport(null);
ChangeHandler alpha = new ChangeHandler();

        System.out.println("adding a listener");
changes.addVetoableChangeListener(alpha);

        System.out.println("trying to fire an event");
alpha.clear();
try {
changes.fireVetoableChange("fred", "foo","bah");
} catch (PropertyVetoException pve) {
pve.printStackTrace();
}
alpha.checkEvent(changes);

System.out.println("passed");
        
  }

}

class NewVetoableChangeSupport extends VetoableChangeSupport {
  public NewVetoableChangeSupport(java.lang.Object source) {
    super(source);
  }
}

class ChangeHandler implements VetoableChangeListener {

    private PropertyChangeEvent lastEvent;

    public void vetoableChange(PropertyChangeEvent evt) {
lastEvent = evt;
    }

    public void checkEvent(Object source) {
        if (lastEvent==null || source!=lastEvent.getSource()) {
System.out.println("failed: wrong event");
System.exit(1);
}
    }

    public void checkNoEvent() {
        if (lastEvent!=null) {
System.out.println("failed: no event expected");
System.exit(2);
}
    }

    public void clear() {
lastEvent = null;
    }
}

==== Here is the output of the test ====

%java TestVCS
passing a null source
adding a listener
trying to fire an event
java.lang.IllegalArgumentException: null source
at java.util.EventObject.<init>(EventObject.java:30)
at java.beans.PropertyChangeEvent.<init>(PropertyChangeEvent.java:54)
at java.beans.VetoableChangeSupport.fireVetoableChange(VetoableChangeSupport.java:143)
at TestVCS.main(TestVCS.java:16)

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