java.awt.event: public class: ContainerEvent

java.awt.event
public class: ContainerEvent [javadoc | source]

java.lang.Object
   java.util.EventObject
      java.awt.AWTEvent
         java.awt.event.ComponentEvent
            java.awt.event.ContainerEvent

All Implemented Interfaces:
Serializable

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 {@code id} parameter of any particular {@code ContainerEvent} instance is not in the range from {@code CONTAINER_FIRST} to {@code CONTAINER_LAST}.

Also see:

ContainerAdapter

ContainerListener

Tutorial: Writing a Container Listener

author: Tim - Prinzing

author: Amy - Fowler

since: 1.1 -

Field 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. Also see: getChild() serial:

Fields inherited from java.awt.event.ComponentEvent:
COMPONENT_FIRST, COMPONENT_LAST, COMPONENT_MOVED, COMPONENT_RESIZED, COMPONENT_SHOWN, COMPONENT_HIDDEN

Fields inherited from java.awt.AWTEvent:
id, consumed, focusManagerIsDispatching, isPosted, COMPONENT_EVENT_MASK, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, WINDOW_EVENT_MASK, ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, ITEM_EVENT_MASK, TEXT_EVENT_MASK, INPUT_METHOD_EVENT_MASK, INPUT_METHODS_ENABLED_MASK, PAINT_EVENT_MASK, INVOCATION_EVENT_MASK, HIERARCHY_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, WINDOW_STATE_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, RESERVED_ID_MAX

Fields inherited from java.awt.AWTEvent:

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

Fields inherited from java.util.EventObject:
source

Constructor:

Constructor:
public ContainerEvent(Component source, int id, Component child) { super(source, id); this.child = 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 Also see: getContainer() getID() getChild()

 public ContainerEvent(Component source,
    int id,
    Component child) {
                                                                                                                                      
        super(source, id);
        this.child = child;
}

ContainerEvent

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

Also see:

getContainer()

getID()

getChild()

Method from java.awt.event.ContainerEvent Summary:
getChild, getContainer, paramString

Methods from java.awt.event.ComponentEvent:
getComponent, paramString

Methods from java.awt.AWTEvent:
consume, convertToOld, copyPrivateDataInto, dispatched, getID, isConsumed, paramString, setSource, toString

Methods from java.util.EventObject:
getSource, toString

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from java.awt.event.ContainerEvent Detail:
public Component getChild() { return child; } Returns the component that was affected by the event.
public Container getContainer() { return (source instanceof Container) ? (Container)source : null; } Returns the originator of the event.
public String paramString() { 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(); } Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.

Method from java.awt.event.ContainerEvent Detail:

 public Component getChild() {
        return child;
}

Returns the component that was affected by the event.

 public Container getContainer() {
        return (source instanceof Container) ? (Container)source : null;
}

Returns the originator of the event.

 public String paramString() {
        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();
}

Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.