Class EventQueueMonitor

java.lang.Object

com.sun.java.accessibility.util.EventQueueMonitor

All Implemented Interfaces:

AWTEventListener, EventListener

public class EventQueueMonitor
extends Object
implements AWTEventListener

The EventQueueMonitor class provides key core functionality for Assistive Technologies (and other system-level technologies that need some of the same things that Assistive Technology needs).

See Also:

• AWTEventMonitor
• SwingEventMonitor

Constructor Summary

Constructors

Constructor	Description
EventQueueMonitor()	Create a new EventQueueMonitor instance.

Method Summary

Modifier and Type	Method	Description
static void	addGUIInitializedListener(GUIInitializedListener l)	Adds the specified listener to be notified when the GUI subsystem is initialized.
static void	addTopLevelWindowListener(TopLevelWindowListener l)	Adds the specified listener to be notified when a top level window is created or destroyed.
void	eventDispatched(AWTEvent theEvent)	Handle events as a result of registering a listener on the EventQueue in maybeInitialize().
static Accessible	getAccessibleAt(Point p)	Obtain the Accessible object at the given point on the Screen.
static Point	getCurrentMousePosition()	Return the last recorded position of the mouse in screen coordinates.
static Window[]	getTopLevelWindows()	Return the list of top level Windows in use in the Java Virtual Machine.
static Window	getTopLevelWindowWithFocus()	Return the top level Window that currently has keyboard focus.
static boolean	isGUIInitialized()	Says whether the GUI subsystem has been initialized or not.
static void	maybeInitialize()	Tell the EventQueueMonitor to start listening for events.
static void	removeGUIInitializedListener(GUIInitializedListener l)	Removes the specified listener to be notified when the GUI subsystem is initialized.
static void	removeTopLevelWindowListener(TopLevelWindowListener l)	Removes the specified listener to be notified when a top level window is created or destroyed.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

EventQueueMonitor

public EventQueueMonitor()

Create a new EventQueueMonitor instance. Normally, this will be called only by the AWT Toolkit during initialization time. Assistive technologies should not create instances of EventQueueMonitor by themselves. Instead, they should either refer to it directly via the static methods in this class, e.g., getCurrentMousePosition() or obtain the instance by asking the Toolkit, e.g., Toolkit.getSystemEventQueue().

Method Details

maybeInitialize

public static void maybeInitialize()

Tell the EventQueueMonitor to start listening for events.

eventDispatched

public void eventDispatched(AWTEvent theEvent)

Handle events as a result of registering a listener on the EventQueue in maybeInitialize().

Specified by:

eventDispatched in interface AWTEventListener

Parameters:

theEvent - the event to be processed

getAccessibleAt

public static Accessible getAccessibleAt(Point p)

Obtain the Accessible object at the given point on the Screen. The return value may be null if an Accessible object cannot be found at the particular point.

Parameters:

p - the point to be accessed

Returns:

the Accessible at the specified point

isGUIInitialized

public static boolean isGUIInitialized()

Says whether the GUI subsystem has been initialized or not. If this returns true, the assistive technology can freely create GUI component instances. If the return value is false, the assistive technology should register a GUIInitializedListener and wait to create GUI component instances until the listener is called.

Returns:

true if the GUI subsystem has been initialized

See Also:

• addGUIInitializedListener(GUIInitializedListener)

addGUIInitializedListener

public static void addGUIInitializedListener(GUIInitializedListener l)

Adds the specified listener to be notified when the GUI subsystem is initialized. Assistive technologies should get the results of isGUIInitialized() before calling this method.

Parameters:

l - the listener to add

See Also:

• isGUIInitialized()
• removeTopLevelWindowListener(TopLevelWindowListener)

removeGUIInitializedListener

public static void removeGUIInitializedListener(GUIInitializedListener l)

Removes the specified listener to be notified when the GUI subsystem is initialized.

Parameters:

l - the listener to remove

See Also:

• addGUIInitializedListener(GUIInitializedListener)

addTopLevelWindowListener

public static void addTopLevelWindowListener(TopLevelWindowListener l)

Adds the specified listener to be notified when a top level window is created or destroyed.

Parameters:

l - the listener to add

See Also:

• removeTopLevelWindowListener(TopLevelWindowListener)

removeTopLevelWindowListener

public static void removeTopLevelWindowListener(TopLevelWindowListener l)

Removes the specified listener to be notified when a top level window is created or destroyed.

Parameters:

l - the listener to remove

See Also:

• addTopLevelWindowListener(TopLevelWindowListener)

getCurrentMousePosition

public static Point getCurrentMousePosition()

Return the last recorded position of the mouse in screen coordinates.

Returns:

the last recorded position of the mouse in screen coordinates

getTopLevelWindows

public static Window[] getTopLevelWindows()

Return the list of top level Windows in use in the Java Virtual Machine.

Returns:

an array of top level Windows in use in the Java Virtual Machine

getTopLevelWindowWithFocus

public static Window getTopLevelWindowWithFocus()

Return the top level Window that currently has keyboard focus.

Returns:

the top level Window that currently has keyboard focus