Class HierarchyEvent
- All Implemented Interfaces:
Serializable
Component
hierarchy to which Component
belongs.
- Hierarchy Change Events (HierarchyListener)
- addition of an ancestor
- removal of an ancestor
- hierarchy made displayable
- hierarchy made undisplayable
- hierarchy shown on the screen (both visible and displayable)
- hierarchy hidden on the screen (either invisible or undisplayable)
- Ancestor Reshape Events (HierarchyBoundsListener)
- an ancestor was resized
- an ancestor was moved
Hierarchy events are provided for notification purposes ONLY. The AWT will automatically handle changes to the hierarchy internally so that GUI layout and displayability works properly regardless of whether a program is receiving these events or not.
This event is generated by a Container object (such as a Panel) when the
Container is added, removed, moved, or resized, and passed down the
hierarchy. It is also generated by a Component object when that object's
addNotify
, removeNotify
, show
, or
hide
method is called. The ANCESTOR_MOVED
and
ANCESTOR_RESIZED
events are dispatched to every HierarchyBoundsListener
or
HierarchyBoundsAdapter
object which registered to receive
such events using the Component's addHierarchyBoundsListener
method. (HierarchyBoundsAdapter
objects implement the
HierarchyBoundsListener
interface.) The HIERARCHY_CHANGED
events are
dispatched to every HierarchyListener
object which registered
to receive such events using the Component's addHierarchyListener
method. Each such listener object gets this HierarchyEvent
when the event occurs.
An unspecified behavior will be caused if the id
parameter
of any particular HierarchyEvent
instance is not
in the range from HIERARCHY_FIRST
to HIERARCHY_LAST
.
The changeFlags
parameter of any HierarchyEvent
instance takes one of the following
values:
-
HierarchyEvent.PARENT_CHANGED
-
HierarchyEvent.DISPLAYABILITY_CHANGED
-
HierarchyEvent.SHOWING_CHANGED
- Since:
- 1.3
- See Also:
-
Field Summary
Modifier and TypeFieldDescriptionstatic final int
The event id indicating an ancestor-Container was moved.static final int
The event id indicating an ancestor-Container was resized.static final int
A change flag indicates that theHIERARCHY_CHANGED
event was generated due to the changing of the hierarchy displayability.static final int
The event id indicating that modification was made to the entire hierarchy tree.static final int
Marks the first integer id for the range of hierarchy event ids.static final int
Marks the last integer id for the range of ancestor event ids.static final int
A change flag indicates that theHIERARCHY_CHANGED
event was generated by a reparenting operation.static final int
A change flag indicates that theHIERARCHY_CHANGED
event was generated due to the changing of the hierarchy showing state.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
ConstructorDescriptionHierarchyEvent
(Component source, int id, Component changed, Container changedParent) Constructs anHierarchyEvent
object to identify a change in theComponent
hierarchy.HierarchyEvent
(Component source, int id, Component changed, Container changedParent, long changeFlags) Constructs anHierarchyEvent
object to identify a change in theComponent
hierarchy. -
Method Summary
Modifier and TypeMethodDescriptionReturns the Component at the top of the hierarchy which was changed.Returns the parent of the Component returned bygetChanged()
.long
Returns a bitmask which indicates the type(s) of HIERARCHY_CHANGED events represented in this event object.Returns the originator of the event.Returns a parameter string identifying this event.Methods inherited from class java.util.EventObject
getSource
-
Field Details
-
HIERARCHY_FIRST
public static final int HIERARCHY_FIRSTMarks the first integer id for the range of hierarchy event ids.- See Also:
-
HIERARCHY_CHANGED
public static final int HIERARCHY_CHANGEDThe event id indicating that modification was made to the entire hierarchy tree.- See Also:
-
ANCESTOR_MOVED
public static final int ANCESTOR_MOVEDThe event id indicating an ancestor-Container was moved.- See Also:
-
ANCESTOR_RESIZED
public static final int ANCESTOR_RESIZEDThe event id indicating an ancestor-Container was resized.- See Also:
-
HIERARCHY_LAST
public static final int HIERARCHY_LASTMarks the last integer id for the range of ancestor event ids.- See Also:
-
PARENT_CHANGED
public static final int PARENT_CHANGEDA change flag indicates that theHIERARCHY_CHANGED
event was generated by a reparenting operation.- See Also:
-
DISPLAYABILITY_CHANGED
public static final int DISPLAYABILITY_CHANGEDA change flag indicates that theHIERARCHY_CHANGED
event was generated due to the changing of the hierarchy displayability. To discern the current displayability of the hierarchy, call theComponent.isDisplayable
method. Displayability changes occur in response to explicit or implicit calls of theComponent.addNotify
andComponent.removeNotify
methods.- See Also:
-
SHOWING_CHANGED
public static final int SHOWING_CHANGEDA change flag indicates that theHIERARCHY_CHANGED
event was generated due to the changing of the hierarchy showing state. To discern the current showing state of the hierarchy, call theComponent.isShowing
method. Showing state changes occur when either the displayability or visibility of the hierarchy occurs. Visibility changes occur in response to explicit or implicit calls of theComponent.show
andComponent.hide
methods.- See Also:
-
-
Constructor Details
-
HierarchyEvent
Constructs anHierarchyEvent
object to identify a change in theComponent
hierarchy.This method throws an
IllegalArgumentException
ifsource
isnull
.- Parameters:
source
- TheComponent
object that originated the eventid
- An integer indicating the type of event. For information on allowable values, see the class description forHierarchyEvent
changed
- TheComponent
at the top of the hierarchy which was changedchangedParent
- The parent of thechanged
component. This may be the parent before or after the change, depending on the type of change- Throws:
IllegalArgumentException
- ifsource
isnull
- See Also:
-
HierarchyEvent
public HierarchyEvent(Component source, int id, Component changed, Container changedParent, long changeFlags) Constructs anHierarchyEvent
object to identify a change in theComponent
hierarchy.This method throws an
IllegalArgumentException
ifsource
isnull
.- Parameters:
source
- TheComponent
object that originated the eventid
- An integer indicating the type of event. For information on allowable values, see the class description forHierarchyEvent
changed
- TheComponent
at the top of the hierarchy which was changedchangedParent
- The parent of thechanged
component. This may be the parent before or after the change, depending on the type of changechangeFlags
- A bitmask which indicates the type(s) of theHIERARCHY_CHANGED
events represented in this event object. For information on allowable values, see the class description forHierarchyEvent
- Throws:
IllegalArgumentException
- ifsource
is null- See Also:
-
-
Method Details
-
getComponent
Returns the originator of the event.- Returns:
- the
Component
object that originated the event, ornull
if the object is not aComponent
.
-
getChanged
Returns the Component at the top of the hierarchy which was changed.- Returns:
- the changed Component
-
getChangedParent
Returns the parent of the Component returned bygetChanged()
. For a HIERARCHY_CHANGED event where the change was of type PARENT_CHANGED via a call toContainer.add
, the parent returned is the parent after the add operation. For a HIERARCHY_CHANGED event where the change was of type PARENT_CHANGED via a call toContainer.remove
, the parent returned is the parent before the remove operation. For all other events and types, the parent returned is the parent during the operation.- Returns:
- the parent of the changed Component
-
getChangeFlags
public long getChangeFlags()Returns a bitmask which indicates the type(s) of HIERARCHY_CHANGED events represented in this event object. The bits have been bitwise-ored together.- Returns:
- the bitmask, or 0 if this is not an HIERARCHY_CHANGED event
-
paramString
Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.- Overrides:
paramString
in classAWTEvent
- Returns:
- a string identifying the event and its attributes
-