- java.lang.Object
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- java.util.EventObject
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- java.awt.AWTEvent
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- java.awt.event.HierarchyEvent
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- All Implemented Interfaces:
Serializable
public class HierarchyEvent extends AWTEvent
An event which indicates a change to theComponenthierarchy to whichComponentbelongs.- 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, orhidemethod is called. TheANCESTOR_MOVEDandANCESTOR_RESIZEDevents are dispatched to everyHierarchyBoundsListenerorHierarchyBoundsAdapterobject which registered to receive such events using the Component'saddHierarchyBoundsListenermethod. (HierarchyBoundsAdapterobjects implement theHierarchyBoundsListenerinterface.) TheHIERARCHY_CHANGEDevents are dispatched to everyHierarchyListenerobject which registered to receive such events using the Component'saddHierarchyListenermethod. Each such listener object gets thisHierarchyEventwhen the event occurs.An unspecified behavior will be caused if the
idparameter of any particularHierarchyEventinstance is not in the range fromHIERARCHY_FIRSTtoHIERARCHY_LAST.
ThechangeFlagsparameter of anyHierarchyEventinstance takes one of the following values:-
HierarchyEvent.PARENT_CHANGED -
HierarchyEvent.DISPLAYABILITY_CHANGED -
HierarchyEvent.SHOWING_CHANGED
- Since:
- 1.3
- See Also:
HierarchyListener,HierarchyBoundsAdapter,HierarchyBoundsListener, Serialized Form
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Field Summary
Fields Modifier and Type Field Description static intANCESTOR_MOVEDThe event id indicating an ancestor-Container was moved.static intANCESTOR_RESIZEDThe event id indicating an ancestor-Container was resized.static intDISPLAYABILITY_CHANGEDA change flag indicates that theHIERARCHY_CHANGEDevent was generated due to the changing of the hierarchy displayability.static intHIERARCHY_CHANGEDThe event id indicating that modification was made to the entire hierarchy tree.static intHIERARCHY_FIRSTMarks the first integer id for the range of hierarchy event ids.static intHIERARCHY_LASTMarks the last integer id for the range of ancestor event ids.static intPARENT_CHANGEDA change flag indicates that theHIERARCHY_CHANGEDevent was generated by a reparenting operation.static intSHOWING_CHANGEDA change flag indicates that theHIERARCHY_CHANGEDevent was generated due to the changing of the hierarchy showing state.-
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
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Fields declared in class java.util.EventObject
source
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Constructor Summary
Constructors Constructor Description HierarchyEvent(Component source, int id, Component changed, Container changedParent)Constructs anHierarchyEventobject to identify a change in theComponenthierarchy.HierarchyEvent(Component source, int id, Component changed, Container changedParent, long changeFlags)Constructs anHierarchyEventobject to identify a change in theComponenthierarchy.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description ComponentgetChanged()Returns the Component at the top of the hierarchy which was changed.ContainergetChangedParent()Returns the parent of the Component returned bygetChanged().longgetChangeFlags()Returns a bitmask which indicates the type(s) of HIERARCHY_CHANGED events represented in this event object.ComponentgetComponent()Returns the originator of the event.StringparamString()Returns a parameter string identifying this event.-
Methods declared in class java.util.EventObject
getSource
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Field Detail
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HIERARCHY_FIRST
public static final int HIERARCHY_FIRST
Marks the first integer id for the range of hierarchy event ids.- See Also:
- Constant Field Values
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HIERARCHY_CHANGED
public static final int HIERARCHY_CHANGED
The event id indicating that modification was made to the entire hierarchy tree.- See Also:
- Constant Field Values
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ANCESTOR_MOVED
public static final int ANCESTOR_MOVED
The event id indicating an ancestor-Container was moved.- See Also:
- Constant Field Values
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ANCESTOR_RESIZED
public static final int ANCESTOR_RESIZED
The event id indicating an ancestor-Container was resized.- See Also:
- Constant Field Values
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HIERARCHY_LAST
public static final int HIERARCHY_LAST
Marks the last integer id for the range of ancestor event ids.- See Also:
- Constant Field Values
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PARENT_CHANGED
public static final int PARENT_CHANGED
A change flag indicates that theHIERARCHY_CHANGEDevent was generated by a reparenting operation.- See Also:
- Constant Field Values
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DISPLAYABILITY_CHANGED
public static final int DISPLAYABILITY_CHANGED
A change flag indicates that theHIERARCHY_CHANGEDevent was generated due to the changing of the hierarchy displayability. To discern the current displayability of the hierarchy, call theComponent.isDisplayablemethod. Displayability changes occur in response to explicit or implicit calls of theComponent.addNotifyandComponent.removeNotifymethods.
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SHOWING_CHANGED
public static final int SHOWING_CHANGED
A change flag indicates that theHIERARCHY_CHANGEDevent was generated due to the changing of the hierarchy showing state. To discern the current showing state of the hierarchy, call theComponent.isShowingmethod. 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.showandComponent.hidemethods.
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Constructor Detail
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HierarchyEvent
public HierarchyEvent(Component source, int id, Component changed, Container changedParent)
Constructs anHierarchyEventobject to identify a change in theComponenthierarchy.This method throws an
IllegalArgumentExceptionifsourceisnull.- Parameters:
source- TheComponentobject that originated the eventid- An integer indicating the type of event. For information on allowable values, see the class description forHierarchyEventchanged- TheComponentat the top of the hierarchy which was changedchangedParent- The parent of thechangedcomponent. This may be the parent before or after the change, depending on the type of change- Throws:
IllegalArgumentException- ifsourceisnull- See Also:
EventObject.getSource(),AWTEvent.getID(),getChanged(),getChangedParent()
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HierarchyEvent
public HierarchyEvent(Component source, int id, Component changed, Container changedParent, long changeFlags)
Constructs anHierarchyEventobject to identify a change in theComponenthierarchy.This method throws an
IllegalArgumentExceptionifsourceisnull.- Parameters:
source- TheComponentobject that originated the eventid- An integer indicating the type of event. For information on allowable values, see the class description forHierarchyEventchanged- TheComponentat the top of the hierarchy which was changedchangedParent- The parent of thechangedcomponent. 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_CHANGEDevents represented in this event object. For information on allowable values, see the class description forHierarchyEvent- Throws:
IllegalArgumentException- ifsourceis null- See Also:
EventObject.getSource(),AWTEvent.getID(),getChanged(),getChangedParent(),getChangeFlags()
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Method Detail
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getComponent
public Component getComponent()
Returns the originator of the event.- Returns:
- the
Componentobject that originated the event, ornullif the object is not aComponent.
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getChanged
public Component getChanged()
Returns the Component at the top of the hierarchy which was changed.- Returns:
- the changed Component
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getChangedParent
public Container 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
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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
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paramString
public String paramString()
Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.- Overrides:
paramStringin classAWTEvent- Returns:
- a string identifying the event and its attributes
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