OpenJDK 27 · java.awt.event.HierarchyEvent · APIdia, the JavaDoc alternative

An event which indicates a change to the 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

Assigning the value different from listed above will cause unspecified behavior.

Field Summary

Modifier and Type	Field and Description
public static final int	ANCESTOR_MOVED The event id indicating an ancestor-Container was moved.
public static final int	ANCESTOR_RESIZED The event id indicating an ancestor-Container was resized.
pack-priv Component	changed
pack-priv Container	changedParent
pack-priv long	changeFlags
public static final int	DISPLAYABILITY_CHANGED A change flag indicates that the `HIERARCHY_CHANGED` event was generated due to the changing of the hierarchy displayability.
public static final int	HIERARCHY_CHANGED The event id indicating that modification was made to the entire hierarchy tree.
public static final int	HIERARCHY_FIRST Marks the first integer id for the range of hierarchy event ids.
public static final int	HIERARCHY_LAST Marks the last integer id for the range of ancestor event ids.
public static final int	PARENT_CHANGED A change flag indicates that the `HIERARCHY_CHANGED` event was generated by a reparenting operation.
private static final long	serialVersionUID Hides java.awt.AWTEvent.serialVersionUID. Use serialVersionUID from JDK 1.6 for interoperability.
public static final int	SHOWING_CHANGED A change flag indicates that the `HIERARCHY_CHANGED` event was generated due to the changing of the hierarchy showing state.

Constructor Summary

Access Constructor and Description

Access	Constructor and Description
public	HierarchyEvent(Component The `Component` object that originated the event source, int An integer indicating the type of event. For information on allowable values, see the class description for `HierarchyEvent` id, Component The `Component` at the top of the hierarchy which was changed changed, Container The parent of the `changed` component. This may be the parent before or after the change, depending on the type of change changedParent) Constructs an `HierarchyEvent` object to identify a change in the `Component` hierarchy.
public	HierarchyEvent(Component The `Component` object that originated the event source, int An integer indicating the type of event. For information on allowable values, see the class description for `HierarchyEvent` id, Component The `Component` at the top of the hierarchy which was changed changed, Container The parent of the `changed` component. This may be the parent before or after the change, depending on the type of change changedParent, long A bitmask which indicates the type(s) of the `HIERARCHY_CHANGED` events represented in this event object. For information on allowable values, see the class description for `HierarchyEvent` changeFlags) Constructs an `HierarchyEvent` object to identify a change in the `Component` hierarchy.

public

HierarchyEvent(Component

The Component object that originated the event

source, int

An integer indicating the type of event. For information on allowable values, see the class description for HierarchyEvent

id, Component

The Component at the top of the hierarchy which was changed

changed, Container

The parent of the changed component. This may be the parent before or after the change, depending on the type of change

changedParent)

Constructs an HierarchyEvent object to identify a change in the Component hierarchy.

public

HierarchyEvent(Component

The Component object that originated the event

source, int

An integer indicating the type of event. For information on allowable values, see the class description for HierarchyEvent

id, Component

The Component at the top of the hierarchy which was changed

changed, Container

The parent of the changed component. This may be the parent before or after the change, depending on the type of change

changedParent, long

A bitmask which indicates the type(s) of the HIERARCHY_CHANGED events represented in this event object. For information on allowable values, see the class description for HierarchyEvent

changeFlags)

Constructs an HierarchyEvent object to identify a change in the Component hierarchy.

Method Summary

Modifier and Type	Method and Description
public Component	Returns: the changed Component getChanged() Returns the Component at the top of the hierarchy which was changed.
public Container	Returns: the parent of the changed Component getChangedParent() Returns the parent of the Component returned by `getChanged()`.
public long	Returns: the bitmask, or 0 if this is not an HIERARCHY_CHANGED event getChangeFlags() Returns a bitmask which indicates the type(s) of HIERARCHY_CHANGED events represented in this event object.
public Component	Returns: the `Component` object that originated the event, or `null` if the object is not a `Component`. getComponent() Returns the originator of the event.
public String	Returns: a string identifying the event and its attributes paramString() Overrides java.awt.AWTEvent.paramString. Returns a parameter string identifying this event.

Inherited from java.awt.AWTEvent:: consume getID isConsumed setSource toString

Field Detail

ANCESTOR_MOVED	back to summary
public static final int ANCESTOR_MOVED The event id indicating an ancestor-Container was moved.

ANCESTOR_RESIZED	back to summary
public static final int ANCESTOR_RESIZED The event id indicating an ancestor-Container was resized.

changed	back to summary
pack-priv Component changed

changedParent	back to summary
pack-priv Container changedParent

changeFlags	back to summary
pack-priv long changeFlags

DISPLAYABILITY_CHANGED back to summary

DISPLAYABILITY_CHANGED	back to summary
public static final int DISPLAYABILITY_CHANGED A change flag indicates that the `HIERARCHY_CHANGED` event was generated due to the changing of the hierarchy displayability. To discern the current displayability of the hierarchy, call the `Component.isDisplayable` method. Displayability changes occur in response to explicit or implicit calls of the `Component.addNotify` and `Component.removeNotify` methods. See Also `java.awt.Component#isDisplayable()`, `java.awt.Component#addNotify()`, `java.awt.Component#removeNotify()`

public static final int DISPLAYABILITY_CHANGED

A change flag indicates that the HIERARCHY_CHANGED event was generated due to the changing of the hierarchy displayability. To discern the current displayability of the hierarchy, call the Component.isDisplayable method. Displayability changes occur in response to explicit or implicit calls of the Component.addNotify and Component.removeNotify methods.

See Also: java.awt.Component#isDisplayable(), java.awt.Component#addNotify(), java.awt.Component#removeNotify()

HIERARCHY_CHANGED	back to summary
public static final int HIERARCHY_CHANGED The event id indicating that modification was made to the entire hierarchy tree.

HIERARCHY_FIRST	back to summary
public static final int HIERARCHY_FIRST Marks the first integer id for the range of hierarchy event ids.

HIERARCHY_LAST	back to summary
public static final int HIERARCHY_LAST Marks the last integer id for the range of ancestor event ids.

PARENT_CHANGED	back to summary
public static final int PARENT_CHANGED A change flag indicates that the `HIERARCHY_CHANGED` event was generated by a reparenting operation.

serialVersionUID	back to summary
private static final long serialVersionUID Hides java.awt.AWTEvent.serialVersionUID. Use serialVersionUID from JDK 1.6 for interoperability. Annotations @Serial

serialVersionUID

back to summary

private static final long serialVersionUID

Hides java.awt.AWTEvent.serialVersionUID.

Use serialVersionUID from JDK 1.6 for interoperability.

Annotations

@Serial

SHOWING_CHANGED back to summary

SHOWING_CHANGED	back to summary
public static final int SHOWING_CHANGED A change flag indicates that the `HIERARCHY_CHANGED` event was generated due to the changing of the hierarchy showing state. To discern the current showing state of the hierarchy, call the `Component.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 the `Component.show` and `Component.hide` methods. See Also `java.awt.Component#isShowing()`, `java.awt.Component#addNotify()`, `java.awt.Component#removeNotify()`, `java.awt.Component#show()`, `java.awt.Component#hide()`

public static final int SHOWING_CHANGED

A change flag indicates that the HIERARCHY_CHANGED event was generated due to the changing of the hierarchy showing state. To discern the current showing state of the hierarchy, call the Component.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 the Component.show and Component.hide methods.

See Also: java.awt.Component#isShowing(), java.awt.Component#addNotify(), java.awt.Component#removeNotify(), java.awt.Component#show(), java.awt.Component#hide()

Constructor Detail

HierarchyEvent back to summary

HierarchyEvent	back to summary
public HierarchyEvent(Component source, int id, Component changed, Container changedParent) Constructs an `HierarchyEvent` object to identify a change in the `Component` hierarchy. This method throws an `IllegalArgumentException` if `source` is `null`. Parameters source:Component The `Component` object that originated the event id:int An integer indicating the type of event. For information on allowable values, see the class description for `HierarchyEvent` changed:Component The `Component` at the top of the hierarchy which was changed changedParent:Container The parent of the `changed` component. This may be the parent before or after the change, depending on the type of change Exceptions IllegalArgumentException: if `source` is `null` See Also `getSource()`, `getID()`, `getChanged()`, `getChangedParent()`

public HierarchyEvent(Component source, int id, Component changed, Container changedParent)

Constructs an HierarchyEvent object to identify a change in the Component hierarchy.

This method throws an IllegalArgumentException if source is null.

Parameters

source:Component: The Component object that originated the event
id:int: An integer indicating the type of event. For information on allowable values, see the class description for HierarchyEvent
changed:Component: The Component at the top of the hierarchy which was changed
changedParent:Container: The parent of the changed component. This may be the parent before or after the change, depending on the type of change

Exceptions

IllegalArgumentException:: if source is null

HierarchyEvent back to summary

HierarchyEvent	back to summary
public HierarchyEvent(Component source, int id, Component changed, Container changedParent, long changeFlags) Constructs an `HierarchyEvent` object to identify a change in the `Component` hierarchy. This method throws an `IllegalArgumentException` if `source` is `null`. Parameters source:Component The `Component` object that originated the event id:int An integer indicating the type of event. For information on allowable values, see the class description for `HierarchyEvent` changed:Component The `Component` at the top of the hierarchy which was changed changedParent:Container The parent of the `changed` component. This may be the parent before or after the change, depending on the type of change changeFlags:long A bitmask which indicates the type(s) of the `HIERARCHY_CHANGED` events represented in this event object. For information on allowable values, see the class description for `HierarchyEvent` Exceptions IllegalArgumentException: if `source` is null See Also `getSource()`, `getID()`, `getChanged()`, `getChangedParent()`, `getChangeFlags()`

public HierarchyEvent(Component source, int id, Component changed, Container changedParent, long changeFlags)

Constructs an HierarchyEvent object to identify a change in the Component hierarchy.

This method throws an IllegalArgumentException if source is null.

Parameters

source:Component: The Component object that originated the event
id:int: An integer indicating the type of event. For information on allowable values, see the class description for HierarchyEvent
changed:Component: The Component at the top of the hierarchy which was changed
changedParent:Container: The parent of the changed component. This may be the parent before or after the change, depending on the type of change
changeFlags:long: A bitmask which indicates the type(s) of the HIERARCHY_CHANGED events represented in this event object. For information on allowable values, see the class description for HierarchyEvent

Exceptions

IllegalArgumentException:: if source is null

Method Detail

getChanged	back to summary
public Component getChanged() Returns the Component at the top of the hierarchy which was changed. Returns:Component the changed Component

getChanged

back to summary

public Component getChanged()

Returns the Component at the top of the hierarchy which was changed.

Returns:Component: the changed Component

getChangedParent back to summary

getChangedParent	back to summary
public Container getChangedParent() Returns the parent of the Component returned by `getChanged()`. For a HIERARCHY_CHANGED event where the change was of type PARENT_CHANGED via a call to `Container.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 to `Container.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:Container the parent of the changed Component

public Container getChangedParent()

Returns the parent of the Component returned by getChanged(). For a HIERARCHY_CHANGED event where the change was of type PARENT_CHANGED via a call to Container.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 to Container.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:Container: the parent of the changed Component

getChangeFlags	back to summary
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:long the bitmask, or 0 if this is not an HIERARCHY_CHANGED event

getChangeFlags

back to summary

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:long: the bitmask, or 0 if this is not an HIERARCHY_CHANGED event

getComponent back to summary

getComponent	back to summary
public Component getComponent() Returns the originator of the event. Returns:Component the `Component` object that originated the event, or `null` if the object is not a `Component`.

public Component getComponent()

Returns the originator of the event.

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

paramString	back to summary
public String paramString() Overrides java.awt.AWTEvent.paramString. Returns a parameter string identifying this event. This method is useful for event-logging and for debugging. Returns:String a string identifying the event and its attributes

paramString

back to summary

public String paramString()

Overrides java.awt.AWTEvent.paramString.

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

Returns:String: a string identifying the event and its attributes

public Class HierarchyEvent

Field Summary

Constructor Summary

Method Summary

Field Detail

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Method Detail