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

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

Constructors

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

Methods

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

Fields

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

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 - 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()

Methods

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

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https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/java/awt/event/ContainerEvent.html