Name: mgC56079 Date: 09/30/97



The ContainerEvent has the constructor:
    public ContainerEvent(Component source, int id, Component child)
should instead have:
    public ContainerEvent(Container source, int id, Component child)

The getContainer() method will fail if the source is not a container
(comment in this method says that cast is always OK. It isn't.)

---- The ContainerEvent's source ----
    /**
     * Constructs a ContainerEvent object.
     *
     * @param source the Component object (container) that originated the event
     * @param id an integer indicating the type of event
     * @param child the component that was added or removed
     */
    public ContainerEvent(Component source, int id, Component child) {
        super(source, id);
        this.child = child;
    }

    /**
     * Returns the originator of the event.
     *
     * @return the Container object that originated the event
     */
    public Container getContainer() {
        return (Container)source; // cast should always be OK, type was checked in constructor
    }

---- Here is the test (CE.java) ----
import java.awt.Button;
import java.awt.Container;
import java.awt.event.ContainerEvent;

public class CE {
public static void main(String[] args) {
  Button b=new Button("label");
  ContainerEvent ce=new ContainerEvent(b,ContainerEvent.COMPONENT_ADDED,b);
  Container c=ce.getContainer();
  System.exit(0); //will not exit under 1.2 without this line
}
}
---- output from the test ----
% java CE
java.lang.ClassCastException: java.awt.Button
at java.awt.event.ContainerEvent.getContainer(ContainerEvent.java:86)
at CE.main(CE.java:9)
-----------

======================================================================