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Class com.sun.java.accessibility.util.EventQueueMonitor

java.lang.Object
   |
   +----java.awt.EventQueue
           |
           +----com.sun.java.accessibility.util.EventQueueMonitor

public class EventQueueMonitor

extends EventQueue

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

This class is meant to be automatically loaded by the Toolkit when it starts up. In order for this to happen, this class needs to be in the CLASSPATH environment variable and the following line needs to be in the awt.properties file:

 AWT.EventQueueClass=com.sun.java.accessibility.util.EventQueueMonitor
 

This class also looks for the AWT.assistive_technologies property in the awt.properties file. This is a comma-separated list of classes that represent assistive technologies that should run in the same Java Virtual Machine as the application. If this property exists, this class will load each class in the list and create a single instance of it in the current thread.

This class is commonly used with one or two other classes, AWTEventMonitor and SwingEventMonitor, that track all events generated by AWT obects and Swing objects respectively.

See Also:

AWTEventMonitor, SwingEventMonitor

EventQueueMonitor()

Create a new EventQueueMonitor instance.

addTopLevelWindowListener(TopLevelWindowListener)

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

getAccessibleAt(Point)

Obtain the Accessible object at the given point on the Screen.

getCurrentMousePosition()

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

getTopLevelWindows()

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

getTopLevelWindowWithFocus()

Return the top level Window that currently has keyboard focus.

maybeLoadAssistiveTechnologies()

Loads additional classes into the Java Virtual Machine using the AWT.assistive_technologies property in the awt.properties file.

postEvent(AWTEvent)

Post a 1.1-style event to the EventQueue.

queueWindowEvent(WindowEvent)

Queue up a WindowEvent for later processing by the WindowEventDispatch thread.

removeTopLevelWindowListener(TopLevelWindowListener)

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

 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., EventQueueMonitor.getCurrentMousePosition) or obtain the instance by asking the Toolkit (e.g., Toolkit.getSystemEventQueue).

 protected static void queueWindowEvent(WindowEvent e)

Queue up a WindowEvent for later processing by the WindowEventDispatch thread.

 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.

 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

 public static void removeTopLevelWindowListener(TopLevelWindowListener l)

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

Parameters:

l - the listener to remove

See Also:

addTopLevelWindowListener

 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

 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

 public static Window getTopLevelWindowWithFocus()

Return the top level Window that currently has keyboard focus.

Returns:

the top level Window that currently has keyboard focus

 public void postEvent(AWTEvent theEvent)

Post a 1.1-style event to the EventQueue.

Parameters:

theEvent - the AWTEvent

Overrides:

postEvent in class EventQueue

 protected static void maybeLoadAssistiveTechnologies()

Loads additional classes into the Java Virtual Machine using the AWT.assistive_technologies property in the awt.properties file. The property specifies a comma-separated list of assistive technology classes this class will load just before the first event is posted to the event queue. The classes will be loaded in the order specified in the property, and a single instance of each will be created.

This will only be done if the JDK version is less than 1.2 because Toolkit.java executes this same code as of JDK1.2.

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