ContainerEvent
Class ContainerEvent
- java.lang.Object
-
- java.util.EventObject
-
- java.awt.AWTEvent
-
- java.awt.event.ComponentEvent
-
- java.awt.event.ContainerEvent
- All Implemented Interfaces:
- Serializable
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.
An unspecified behavior will be caused if the id
parameter of any particular ContainerEvent
instance is not in the range from CONTAINER_FIRST
to CONTAINER_LAST
.
- Since:
- 1.1
- See Also:
-
ContainerAdapter
,ContainerListener
, Tutorial: Writing a Container Listener, Serialized Form
Fields
CONTAINER_FIRST
public static final int CONTAINER_FIRST
The first number in the range of ids used for container events.
CONTAINER_LAST
public static final int CONTAINER_LAST
The last number in the range of ids used for container events.
COMPONENT_ADDED
public static final int COMPONENT_ADDED
This event indicates that a component was added to the container.
COMPONENT_REMOVED
public static final int COMPONENT_REMOVED
This event indicates that a component was removed from the container.
Constructors
ContainerEvent
public ContainerEvent(Component source, int id, Component child)
Constructs a ContainerEvent
object.
This method throws an IllegalArgumentException
if source
is null
.
- Parameters:
-
source
- TheComponent
object (container) that originated the event -
id
- An integer indicating the type of event. For information on allowable values, see the class description forContainerEvent
-
child
- the component that was added or removed - Throws:
-
IllegalArgumentException
- ifsource
is null - See Also:
-
getContainer()
,AWTEvent.getID()
,getChild()
Methods
getContainer
public Container getContainer()
Returns the originator of the event.
- Returns:
- the
Container
object that originated the event, ornull
if the object is not aContainer
.
getChild
public Component getChild()
Returns the component that was affected by the event.
- Returns:
- the Component object that was added or removed
paramString
public String paramString()
Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.
- Overrides:
-
paramString
in classComponentEvent
- Returns:
- a string identifying the event and its attributes
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