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ContainerEvent.javaAPI DocJava SE 6 API4351Tue Jun 10 00:25:24 BST 2008java.awt.event

ContainerEvent

public class ContainerEvent extends ComponentEvent
A low-level event which indicates that a container's contents changed because a component was added or removed.

Container events are provided for notification purposes ONLY; The AWT will automatically handle changes to the containers contents internally so that the program works properly regardless of whether the program is receiving these events or not.

This low-level event is generated by a container object (such as a Panel) when a component is added to it or removed from it. The event is passed to every ContainerListener or ContainerAdapter object which registered to receive such events using the component's addContainerListener method. (ContainerAdapter objects implement the ContainerListener interface.) Each such listener object gets this ContainerEvent when the event occurs.

see
ContainerAdapter
see
ContainerListener
see
Tutorial: Writing a Container Listener
author
Tim Prinzing
author
Amy Fowler
version
1.20 04/13/06
since
1.1

Fields Summary
public static final int
CONTAINER_FIRST
The first number in the range of ids used for container events.
public static final int
CONTAINER_LAST
The last number in the range of ids used for container events.
public static final int
COMPONENT_ADDED
This event indicates that a component was added to the container.
public static final int
COMPONENT_REMOVED
This event indicates that a component was removed from the container.
Component
child
The non-null component that is being added or removed from the Container.
private static final long
serialVersionUID
Constructors Summary
public ContainerEvent(Component source, int id, Component child)
Constructs a ContainerEvent object.

Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null.

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
throws
IllegalArgumentException if source is null


                                                                                       
           
        super(source, id);
        this.child = child;
Methods Summary
public java.awt.ComponentgetChild()
Returns the component that was affected by the event.

return
the Component object that was added or removed

        return child;
public java.awt.ContainergetContainer()
Returns the originator of the event.

return
the Container object that originated the event, or null if the object is not a Container.

        return (source instanceof Container) ? (Container)source : null;
public java.lang.StringparamString()
Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.

return
a string identifying the event and its attributes

        String typeStr;
        switch(id) {
          case COMPONENT_ADDED:
              typeStr = "COMPONENT_ADDED";
              break;
          case COMPONENT_REMOVED:
              typeStr = "COMPONENT_REMOVED";
              break;
          default:
              typeStr = "unknown type";
        }
        return typeStr + ",child="+child.getName();