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

Field Summary

Fields

Modifier and Type	Field	Description
static final int	COMPONENT_ADDED	This event indicates that a component was added to the container.
static final int	COMPONENT_REMOVED	This event indicates that a component was removed from the container.
static final int	CONTAINER_FIRST	The first number in the range of ids used for container events.
static final int	CONTAINER_LAST	The last number in the range of ids used for container events.

Fields declared in class java.awt.event.ComponentEvent

COMPONENT_FIRST, COMPONENT_HIDDEN, COMPONENT_LAST, COMPONENT_MOVED, COMPONENT_RESIZED, COMPONENT_SHOWN

Fields declared in class java.awt.AWTEvent

ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, COMPONENT_EVENT_MASK, consumed, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, HIERARCHY_EVENT_MASK, id, INPUT_METHOD_EVENT_MASK, INVOCATION_EVENT_MASK, ITEM_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, PAINT_EVENT_MASK, RESERVED_ID_MAX, TEXT_EVENT_MASK, WINDOW_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, WINDOW_STATE_EVENT_MASK

Fields declared in class java.util.EventObject

source

Constructor Summary

Constructors

Constructor	Description
ContainerEvent(Component source, int id, Component child)	Constructs a ContainerEvent object.

Method Summary

Modifier and Type	Method	Description
Component	getChild()	Returns the component that was affected by the event.
Container	getContainer()	Returns the originator of the event.
String	paramString()	Returns a parameter string identifying this event.

Methods declared in class java.awt.event.ComponentEvent

getComponent

Methods declared in class java.awt.AWTEvent

consume, getID, isConsumed, setSource, toString

Methods declared in class java.util.EventObject

getSource

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

CONTAINER_FIRST

public static final int CONTAINER_FIRST

The first number in the range of ids used for container events.

See Also:

• Constant Field Values

CONTAINER_LAST

public static final int CONTAINER_LAST

The last number in the range of ids used for container events.

See Also:

• Constant Field Values

COMPONENT_ADDED

public static final int COMPONENT_ADDED

This event indicates that a component was added to the container.

See Also:

• Constant Field Values

COMPONENT_REMOVED

public static final int COMPONENT_REMOVED

This event indicates that a component was removed from the container.

See Also:

• Constant Field Values

Constructor Details

ContainerEvent

public ContainerEvent(Component source,
 int id,
 Component child)

Constructs a ContainerEvent object.

This method throws an IllegalArgumentException if source is null.

Parameters:

source - The Component object (container) that originated the event

id - An integer indicating the type of event. For information on allowable values, see the class description for ContainerEvent

child - the component that was added or removed

Throws:

IllegalArgumentException - if source is null

See Also:

• getContainer()
• AWTEvent.getID()
• getChild()

Method Details

getContainer

public Container getContainer()

Returns the originator of the event.

Returns:

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

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 class ComponentEvent

Returns:

a string identifying the event and its attributes