java.awt.event

Class HierarchyEvent

public class HierarchyEvent extends AWTEvent

This class represents an event generated for an ancestor component which may affect this component. These events normally do not need to be handled by the application, since the AWT system automatically takes care of them.

There are two types of hierarchy events. The first type is handled by HierarchyListener, and includes addition or removal of an ancestor, or an ancestor changing its on-screen status (visible and/or displayble). The second type is handled by HierarchyBoundsListener, and includes resizing or moving of an ancestor.

Since: 1.3

UNKNOWN: updated to 1.4

Field Summary
static int	ANCESTOR_MOVED This id indicates that an ancestor was moved.
static int	ANCESTOR_RESIZED This id indicates that an ancestor was resized.
static int	DISPLAYABILITY_CHANGED This indicates that the HIERARCHY_CHANGED is caused by a change in displayability.
static int	HIERARCHY_CHANGED This id indicates that the hierarchy tree changed.
static int	HIERARCHY_FIRST This is the first id in the range of ids used by this class.
static int	HIERARCHY_LAST This is the last id in the range of ids used by this class.
static int	PARENT_CHANGED This indicates that the HIERARCHY_CHANGED is a changed parent.
static int	SHOWING_CHANGED This indicates that the HIERARCHY_CHANGED is a changed visibility.

Constructor Summary
	HierarchyEvent(Component source, int id, Component changed, Container changedParent) Initializes a new instance of `HierarchyEvent` with the specified parameters.
	HierarchyEvent(Component source, int id, Component changed, Container changedParent, long changeFlags) Initializes a new instance of `HierarchyEvent` with the specified parameters.

Method Summary
Component	getChanged() Returns the component at the top of the hierarchy which changed.
Container	getChangedParent() Returns the parent of the component listed in `getChanged()`.
long	getChangeFlags() If this is a HIERARCHY_CHANGED event, this returns a bitmask of the types of changes that took place.
Component	getComponent() This method returns the event source as a `Component`.
String	paramString() This method returns a string identifying this event.

Field Detail

ANCESTOR_MOVED

public static final int ANCESTOR_MOVED

This id indicates that an ancestor was moved.

ANCESTOR_RESIZED

public static final int ANCESTOR_RESIZED

This id indicates that an ancestor was resized.

DISPLAYABILITY_CHANGED

public static final int DISPLAYABILITY_CHANGED

This indicates that the HIERARCHY_CHANGED is caused by a change in displayability.

HIERARCHY_CHANGED

public static final int HIERARCHY_CHANGED

This id indicates that the hierarchy tree changed.

HIERARCHY_FIRST

public static final int HIERARCHY_FIRST

This is the first id in the range of ids used by this class.

HIERARCHY_LAST

public static final int HIERARCHY_LAST

This is the last id in the range of ids used by this class.

PARENT_CHANGED

public static final int PARENT_CHANGED

This indicates that the HIERARCHY_CHANGED is a changed parent.

SHOWING_CHANGED

public static final int SHOWING_CHANGED

This indicates that the HIERARCHY_CHANGED is a changed visibility.

Constructor Detail

HierarchyEvent

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

Initializes a new instance of HierarchyEvent with the specified parameters. Note that an invalid id leads to unspecified results.

Parameters: source the component whose hierarchy changed id the event id changed the top component in the tree of changed hierarchy changedParent the updated parent of this object

Throws: IllegalArgumentException if source is null

HierarchyEvent

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

Initializes a new instance of HierarchyEvent with the specified parameters. Note that an invalid id leads to unspecified results.

Parameters: source the component whose hierarchy changed id the event id changed the top component in the tree of changed hierarchy changedParent the updated parent of this object changeFlags the bitmask of specific HIERARCHY_CHANGED events

Throws: IllegalArgumentException if source is null

Method Detail

getChanged

public Component getChanged()

Returns the component at the top of the hierarchy which changed.

Returns: the top changed component

getChangedParent

public Container getChangedParent()

Returns the parent of the component listed in getChanged(). If the cause of this event was Container.add, this is the new parent; if the cause was Container.remove, this is the old parent; otherwise it is the unchanged parent.

Returns: the parent container of the changed component

getChangeFlags

public long getChangeFlags()

If this is a HIERARCHY_CHANGED event, this returns a bitmask of the types of changes that took place.

Returns: the bitwise or of hierarchy change types, or 0

getComponent

public Component getComponent()

This method returns the event source as a Component. If the source has subsequently been modified to a non-Component, this returns null.

Returns: the event source as a Component, or null

paramString

public String paramString()

This method returns a string identifying this event. This is the field name of the id type, followed by a parenthesized listing of the changed component and its parent container. In addition, if the type is HIERARCHY_CHANGED, the flags preceed the changed component, in the order PARENT_CHANGED, DISPLAYABILITY_CHANGED, and SHOWING_CHANGED.

Returns: a string identifying this event