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## java.awt.event
Class ComponentEvent

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

All Implemented Interfaces:
  Serializable

Direct Known Subclasses:
  ContainerEvent, FocusEvent, InputEvent, PaintEvent, WindowEvent

    public class ComponentEvent

extends AWTEvent

A low-level event which indicates that a component moved, changed size, or changed visibility (also, the root class for the other component-level events).

Component events are provided for notification purposes ONLY; The AWT will automatically handle component moves and resizes internally so that GUI layout works properly regardless of whether a program is receiving these events or not.

In addition to serving as the base class for other component-related events (InputEvent, FocusEvent, WindowEvent, ContainerEvent), this class defines the events that indicate changes in a component's size, position, or visibility.

This low-level event is generated by a component object (such as a List) when the component is moved, resized, rendered invisible, or made visible again. The event is passed to every `ComponentListener` or `ComponentAdapter` object which registered to receive such events using the component's `addComponentListener` method. (`ComponentAdapter` objects implement the `ComponentListener` interface.) Each such listener object gets this `ComponentEvent` when the event occurs.

Since:
  1.1
See Also:
  `ComponentAdapter`, `ComponentListener`, Tutorial: Writing a Component Listener, Reference: The Java Class Libraries (update file), Serialized Form

Field Summary
`static int` | `COMPONENT_FIRST` The first number in the range of ids used for component events.
`static int` | `COMPONENT_HIDDEN` This event indicates that the component was rendered invisible.
`static int` | `COMPONENT_LAST` The last number in the range of ids used for component events.
`static int` | `COMPONENT_MOVED` This event indicates that the component's position changed.
`static int` | `COMPONENT_RESIZED` This event indicates that the component's size changed.
`static int` | `COMPONENT_SHOWN` This event indicates that the component was made visible.

Fields inherited from 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 inherited from class java.util.EventObject
`source`

Constructor Summary
`ComponentEvent(Component source, int id)` Constructs a `ComponentEvent` object.

Method Summary
`Component` | `getComponent()` Returns the originator of the event.
`String` | `paramString()` Returns a parameter string identifying this event.

Methods inherited from class java.awt.AWTEvent
`consume, getID, isConsumed, setSource, toString`

Methods inherited from class java.util.EventObject
`getSource`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Field Detail

### COMPONENT_FIRST

    public static final int COMPONENT_FIRST

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

  See Also:
    Constant Field Values

### COMPONENT_LAST

    public static final int COMPONENT_LAST

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

  See Also:
    Constant Field Values

### COMPONENT_MOVED

    public static final int COMPONENT_MOVED

  This event indicates that the component's position changed.

  See Also:
    Constant Field Values

### COMPONENT_RESIZED

    public static final int COMPONENT_RESIZED

  This event indicates that the component's size changed.

  See Also:
    Constant Field Values

### COMPONENT_SHOWN

    public static final int COMPONENT_SHOWN

  This event indicates that the component was made visible.

  See Also:
    Constant Field Values

### COMPONENT_HIDDEN

    public static final int COMPONENT_HIDDEN

  This event indicates that the component was rendered invisible.

  See Also:
    Constant Field Values

Constructor Detail

### ComponentEvent

    public ComponentEvent(Component source,
                          int id)

  Constructs a `ComponentEvent` object.

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

  Parameters:
    `source` - the `Component` that originated the event
    `id` - an integer indicating the type of event
  Throws:
    `IllegalArgumentException` - if `source` is null

Method Detail

### getComponent

    public Component getComponent()

  Returns the originator of the event.

  Returns:
    the `Component` object that originated the event, or `null` if the object is not a `Component`.

### 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 `AWTEvent`
  Returns:
    a string identifying the event and its attributes

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.