org.eclipse.swt.widgets
Class Display

java.lang.Object
  org.eclipse.swt.graphics.Device
      org.eclipse.swt.widgets.Display

All Implemented Interfaces:

Adaptable, Drawable

public class Display

extends Device

implements Adaptable

Instances of this class are responsible for managing the connection between SWT and the underlying operating system. Their most important function is to implement the SWT event loop in terms of the platform event model. They also provide various methods for accessing information about the operating system, and have overall control over the operating system resources which SWT allocates.

Applications which are built with SWT will almost always require only a single display. In particular, some platforms which SWT supports will not allow more than one active display. In other words, some platforms do not support creating a new display if one already exists that has not been sent the dispose() message.

In SWT, the thread which creates a Display instance is distinguished as the user-interface thread for that display.

The user-interface thread for a particular display has the following special attributes:

• The event loop for that display must be run from the thread.
• Some SWT API methods (notably, most of the public methods in Widget and its subclasses), may only be called from the thread. (To support multi-threaded user-interface applications, class Display provides inter-thread communication methods which allow threads other than the user-interface thread to request that it perform operations on their behalf.)
• The thread is not allowed to construct other Displays until that display has been disposed. (Note that, this is in addition to the restriction mentioned above concerning platform support for multiple displays. Thus, the only way to have multiple simultaneously active displays, even on platforms which support it, is to have multiple threads.)

Enforcing these attributes allows SWT to be implemented directly on the underlying operating system's event model. This has numerous benefits including smaller footprint, better use of resources, safer memory management, clearer program logic, better performance, and fewer overall operating system threads required. The down side however, is that care must be taken (only) when constructing multi-threaded applications to use the inter-thread communication mechanisms which this class provides when required.

All SWT API methods which may only be called from the user-interface thread are distinguished in their documentation by indicating that they throw the "ERROR_THREAD_INVALID_ACCESS" SWT exception.

Styles:

(none)

Events:

Close, Dispose, Skin

IMPORTANT: This class is not intended to be subclassed.

Since:

1.0

See Also:

syncExec(java.lang.Runnable), asyncExec(java.lang.Runnable), wake(), readAndDispatch(), sleep(), Device.dispose()

Field Summary

Fields inherited from class org.eclipse.swt.graphics.Device

deviceLock

Constructor Summary

Display()
Constructs a new instance of this class.

Method Summary

void	addFilter(int eventType, Listener listener) Adds the listener to the collection of listeners who will be notified when an event of the given type occurs anywhere in a widget.
void	addListener(int eventType, Listener listener) Adds the listener to the collection of listeners who will be notified when an event of the given type occurs.
void	asyncExec(Runnable runnable) Causes the run() method of the runnable to be invoked by the user-interface thread at the next reasonable opportunity.
void	beep() Causes the system hardware to emit a short sound (if it supports this capability).
protected void	checkDevice() Throws an SWTException if the receiver can not be accessed by the caller.
void	close() Requests that the connection between SWT and the underlying operating system be closed.
protected void	destroy() Destroys the device .
void	disposeExec(Runnable runnable) Causes the run() method of the runnable to be invoked by the user-interface thread just before the receiver is disposed.
static Display	findDisplay(Thread thread) Returns the display which the given thread is the user-interface thread for, or null if the given thread is not a user-interface thread for any display.
Shell	getActiveShell() Returns the currently active Shell, or null if no shell belonging to the currently running application is active.
Object	getAdapter(Class adapter) Returns an object which is an instance of the given class parameter associated with this object or null if no association exists.
static String	getAppName() Returns the application name.
static String	getAppVersion() Returns the application version.
Rectangle	getBounds() Returns a rectangle describing the receiver's size and location.
static Display	getCurrent() Returns the display which the currently running thread is the user-interface thread for, or null if the currently running thread is not a user-interface thread for any display.
Control	getCursorControl() Returns the control which the on-screen pointer is currently over top of, or null if it is not currently over one of the controls built by the currently running application.
Point	getCursorLocation() Returns the location of the on-screen pointer relative to the top left corner of the screen.
Object	getData() Returns the application defined, display specific data associated with the receiver, or null if it has not been set.
Object	getData(String key) Returns the application defined property of the receiver with the specified name, or null if it has not been set.
static Display	getDefault() Returns the default display.
int	getDismissalAlignment() Returns the button dismissal alignment, one of LEFT or RIGHT.
int	getDoubleClickTime() Returns the longest duration, in milliseconds, between two mouse button clicks that will be considered a double click .
Control	getFocusControl() Returns the control which currently has keyboard focus, or null if keyboard events are not currently going to any of the controls built by the currently running application.
boolean	getHighContrast() Returns true when the high contrast mode is enabled.
Menu	getMenuBar() Returns the single instance of the application menu bar or null when there is no application menu bar for the platform.
Monitor[]	getMonitors() Returns an array of monitors attached to the device.
Monitor	getPrimaryMonitor() Returns the primary monitor for that device.
Shell[]	getShells() Returns a (possibly empty) array containing all shells which have not been disposed and have the receiver as their display.
Synchronizer	getSynchronizer() Gets the synchronizer used by the display.
Thread	getSyncThread() Returns the thread that has invoked syncExec or null if no such runnable is currently being invoked by the user-interface thread.
Color	getSystemColor(int id) Returns the matching standard color for the given constant, which should be one of the color constants specified in class SWT.
Cursor	getSystemCursor(int id) Returns the matching standard platform cursor for the given constant, which should be one of the cursor constants specified in class SWT.
Image	getSystemImage(int id) Returns the matching standard platform image for the given constant, which should be one of the icon constants specified in class SWT.
Menu	getSystemMenu() Returns the single instance of the system-provided menu for the application.
TaskBar	getSystemTaskBar() Returns the single instance of the system taskBar or null when there is no system taskBar available for the platform.
Tray	getSystemTray() Returns the single instance of the system tray or null when there is no system tray available for the platform.
Thread	getThread() Returns the user-interface thread for the receiver.
boolean	getTouchEnabled() Returns true if a touch-aware input device is attached to the system, enabled, and ready for use.
Point	map(Control from, Control to, int x, int y) Maps a point from one coordinate system to another.
Rectangle	map(Control from, Control to, int x, int y, int width, int height) Maps a point from one coordinate system to another.
Point	map(Control from, Control to, Point point) Maps a point from one coordinate system to another.
Rectangle	map(Control from, Control to, Rectangle rectangle) Maps a point from one coordinate system to another.
boolean	readAndDispatch() Reads an event from the event queue, dispatches it appropriately, and returns true if there is potentially more work to do, or false if the caller can sleep until another event is placed on the event queue.
protected void	release() Releases any internal resources .
void	removeFilter(int eventType, Listener listener) Removes the listener from the collection of listeners who will be notified when an event of the given type occurs anywhere in a widget.
void	removeListener(int eventType, Listener listener) Removes the listener from the collection of listeners who will be notified when an event of the given type occurs.
static void	setAppName(String name) Sets the application name to the argument.
static void	setAppVersion(String version) Sets the application version to the argument.
void	setData(Object data) Sets the application defined, display specific data associated with the receiver, to the argument.
void	setData(String key, Object value) Sets the application defined property of the receiver with the specified name to the given argument.
void	setSynchronizer(Synchronizer synchronizer) Sets the synchronizer used by the display to be the argument, which can not be null.
boolean	sleep() Causes the user-interface thread to sleep (that is, to be put in a state where it does not consume CPU cycles) until an event is received or it is otherwise awakened.
void	syncExec(Runnable runnable) Causes the run() method of the runnable to be invoked by the user-interface thread at the next reasonable opportunity.
void	timerExec(int milliseconds, Runnable runnable) Causes the run() method of the runnable to be invoked by the user-interface thread after the specified number of milliseconds have elapsed.
void	update() Forces all outstanding paint requests for the display to be processed before this method returns.
void	wake() Notifies the client side to send a life cycle request as UI thread to perform UI-updates.

Methods inherited from class org.eclipse.swt.graphics.Device

dispose, getClientArea, getDepth, getDPI, getFontList, getSystemFont, isDisposed

Methods inherited from class java.lang.Object

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

Constructor Detail

Display

public Display()

Constructs a new instance of this class.

Note: The resulting display is marked as the current display. If this is the first display which has been constructed since the application started, it is also marked as the default display.

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if called from a thread that already created an existing display
• ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass

See Also:

getCurrent(), getDefault(), Widget.checkSubclass(), Shell

Method Detail

getCurrent

public static Display getCurrent()

Returns the display which the currently running thread is the user-interface thread for, or null if the currently running thread is not a user-interface thread for any display.

Returns:

the current display

getDefault

public static Display getDefault()

Returns the default display. One is created if it did not already exist.

Note: In RWT, a new display is only created if the calling thread is the user-interface thread.

Returns:

the default display

getBounds

public Rectangle getBounds()

Returns a rectangle describing the receiver's size and location.

Overrides:

getBounds in class Device

Returns:

the bounding rectangle

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

getFocusControl

public Control getFocusControl()

Returns the control which currently has keyboard focus, or null if keyboard events are not currently going to any of the controls built by the currently running application.

Returns:

the control under the cursor

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

map

public Point map(Control from,
                 Control to,
                 Point point)

Maps a point from one coordinate system to another. When the control is null, coordinates are mapped to the display.

NOTE: On right-to-left platforms where the coordinate systems are mirrored, special care needs to be taken when mapping coordinates from one control to another to ensure the result is correctly mirrored. Mapping a point that is the origin of a rectangle and then adding the width and height is not equivalent to mapping the rectangle. When one control is mirrored and the other is not, adding the width and height to a point that was mapped causes the rectangle to extend in the wrong direction. Mapping the entire rectangle instead of just one point causes both the origin and the corner of the rectangle to be mapped.

Parameters:

from - the source Control or null

to - the destination Control or null

point - to be mapped

Returns:

point with mapped coordinates

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the point is null
• ERROR_INVALID_ARGUMENT - if the Control from or the Control to have been disposed

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

map

public Point map(Control from,
                 Control to,
                 int x,
                 int y)

Maps a point from one coordinate system to another. When the control is null, coordinates are mapped to the display.

NOTE: On right-to-left platforms where the coordinate systems are mirrored, special care needs to be taken when mapping coordinates from one control to another to ensure the result is correctly mirrored. Mapping a point that is the origin of a rectangle and then adding the width and height is not equivalent to mapping the rectangle. When one control is mirrored and the other is not, adding the width and height to a point that was mapped causes the rectangle to extend in the wrong direction. Mapping the entire rectangle instead of just one point causes both the origin and the corner of the rectangle to be mapped.

Parameters:

from - the source Control or null

to - the destination Control or null

x - coordinates to be mapped

y - coordinates to be mapped

Returns:

point with mapped coordinates

Throws:

IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the Control from or the Control to have been disposed

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

map

public Rectangle map(Control from,
                     Control to,
                     Rectangle rectangle)

Maps a point from one coordinate system to another. When the control is null, coordinates are mapped to the display.

NOTE: On right-to-left platforms where the coordinate systems are mirrored, special care needs to be taken when mapping coordinates from one control to another to ensure the result is correctly mirrored. Mapping a point that is the origin of a rectangle and then adding the width and height is not equivalent to mapping the rectangle. When one control is mirrored and the other is not, adding the width and height to a point that was mapped causes the rectangle to extend in the wrong direction. Mapping the entire rectangle instead of just one point causes both the origin and the corner of the rectangle to be mapped.

Parameters:

from - the source Control or null

to - the destination Control or null

rectangle - to be mapped

Returns:

rectangle with mapped coordinates

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the rectangle is null
• ERROR_INVALID_ARGUMENT - if the Control from or the Control to have been disposed

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

map

public Rectangle map(Control from,
                     Control to,
                     int x,
                     int y,
                     int width,
                     int height)

Maps a point from one coordinate system to another. When the control is null, coordinates are mapped to the display.

NOTE: On right-to-left platforms where the coordinate systems are mirrored, special care needs to be taken when mapping coordinates from one control to another to ensure the result is correctly mirrored. Mapping a point that is the origin of a rectangle and then adding the width and height is not equivalent to mapping the rectangle. When one control is mirrored and the other is not, adding the width and height to a point that was mapped causes the rectangle to extend in the wrong direction. Mapping the entire rectangle instead of just one point causes both the origin and the corner of the rectangle to be mapped.

Parameters:

from - the source Control or null

to - the destination Control or null

x - coordinates to be mapped

y - coordinates to be mapped

width - coordinates to be mapped

height - coordinates to be mapped

Returns:

rectangle with mapped coordinates

Throws:

IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the Control from or the Control to have been disposed

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

addListener

public void addListener(int eventType,
                        Listener listener)

Adds the listener to the collection of listeners who will be notified when an event of the given type occurs. The event type is one of the event constants defined in class SWT. When the event does occur in the display, the listener is notified by sending it the handleEvent() message.

Parameters:

eventType - the type of event to listen for

listener - the listener which should be notified when the event occurs

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

See Also:

Listener, SWT, removeListener(int, org.eclipse.swt.widgets.Listener)

removeListener

public void removeListener(int eventType,
                           Listener listener)

Removes the listener from the collection of listeners who will be notified when an event of the given type occurs. The event type is one of the event constants defined in class SWT.

Parameters:

eventType - the type of event to listen for

listener - the listener which should no longer be notified

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

See Also:

Listener, SWT, addListener(int, org.eclipse.swt.widgets.Listener)

disposeExec

public void disposeExec(Runnable runnable)

Causes the run() method of the runnable to be invoked by the user-interface thread just before the receiver is disposed. Specifying a null runnable is ignored.

Parameters:

runnable - code to run at dispose time.

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

close

public void close()

Requests that the connection between SWT and the underlying operating system be closed.

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

See Also:

Device.dispose()

release

protected void release()

Description copied from class: Device

Releases any internal resources .

When a device is destroyed, resources that were acquired on behalf of the programmer need to be returned to the operating system. For example, if the device allocated a font to be used as the system font, this font would be freed in release. Also,to assist the garbage collector and minimize the amount of memory that is not reclaimed when the programmer keeps a reference to a disposed device, all fields except the handle are zero'd. The handle is needed by destroy.

This method is called before destroy.

If subclasses reimplement this method, they must call the super implementation.

Overrides:

release in class Device

See Also:

Device.dispose(), Device.destroy()

destroy

protected void destroy()

Description copied from class: Device

Destroys the device . If the device does not have a handle, this method may do nothing depending on the device.

This method is called after release.

Subclasses are supposed to reimplement this method and not call the super implementation.

Overrides:

destroy in class Device

See Also:

Device.dispose(), Device.release()

getAdapter

public Object getAdapter(Class adapter)

Description copied from interface: Adaptable

Returns an object which is an instance of the given class parameter associated with this object or null if no association exists.

Specified by:

getAdapter in interface Adaptable

Parameters:

adapter - the lookup class

Returns:

a object castable to the given class or null if there is no adapter associated with the given class.

getShells

public Shell[] getShells()

Returns a (possibly empty) array containing all shells which have not been disposed and have the receiver as their display.

Returns:

the receiver's shells

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

getActiveShell

public Shell getActiveShell()

Returns the currently active Shell, or null if no shell belonging to the currently running application is active.

Returns:

the active shell or null

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

getThread

public Thread getThread()

Returns the user-interface thread for the receiver. Note that the user-interface thread may change per user-request.

Returns:

the receiver's user-interface thread or null if there's no current user-request executed that belongs to the display.

Throws:

SWTException -

• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

findDisplay

public static Display findDisplay(Thread thread)

Returns the display which the given thread is the user-interface thread for, or null if the given thread is not a user-interface thread for any display. Specifying null as the thread will return null for the display.

Parameters:

thread - the user-interface thread

Returns:

the display for the given thread

Since:

1.3

setSynchronizer

public void setSynchronizer(Synchronizer synchronizer)

Sets the synchronizer used by the display to be the argument, which can not be null.

Parameters:

synchronizer - the new synchronizer for the display (must not be null)

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the synchronizer is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed
• ERROR_FAILED_EXEC - if an exception occurred while running an inter-thread message

Since:

1.3

getSynchronizer

public Synchronizer getSynchronizer()

Gets the synchronizer used by the display.

Returns:

the receiver's synchronizer

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

getSyncThread

public Thread getSyncThread()

Returns the thread that has invoked syncExec or null if no such runnable is currently being invoked by the user-interface thread.

Note: If a runnable invoked by asyncExec is currently running, this method will return null.

Returns:

the receiver's sync-interface thread

Throws:

SWTException -

• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

asyncExec

public void asyncExec(Runnable runnable)

Causes the run() method of the runnable to be invoked by the user-interface thread at the next reasonable opportunity. Note that the user-interface thread may change per user-request. The caller of this method continues to run in parallel, and is not notified when the runnable has completed. Specifying null as the runnable simply wakes the user-interface thread when run.

Note that at the time the runnable is invoked, widgets that have the receiver as their display may have been disposed. Therefore, it is necessary to check for this case inside the runnable before accessing the widget.

Parameters:

runnable - code to run on the user-interface thread or null

Throws:

SWTException -

• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

See Also:

syncExec(java.lang.Runnable)

syncExec

public void syncExec(Runnable runnable)

Causes the run() method of the runnable to be invoked by the user-interface thread at the next reasonable opportunity. Note that the user-interface thread may change per user-request. The thread which calls this method is suspended until the runnable completes. Specifying null as the runnable simply wakes the user-interface thread.

Note that at the time the runnable is invoked, widgets that have the receiver as their display may have been disposed. Therefore, it is necessary to check for this case inside the runnable before accessing the widget.

Parameters:

runnable - code to run on the user-interface thread or null

Throws:

SWTException -

• ERROR_FAILED_EXEC - if an exception occured when executing the runnable
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

See Also:

asyncExec(java.lang.Runnable)

timerExec

public void timerExec(int milliseconds,
                      Runnable runnable)

Causes the run() method of the runnable to be invoked by the user-interface thread after the specified number of milliseconds have elapsed. If milliseconds is less than zero, the runnable is not executed.

Note that at the time the runnable is invoked, widgets that have the receiver as their display may have been disposed. Therefore, it is necessary to check for this case inside the runnable before accessing the widget.

Parameters:

milliseconds - the delay before running the runnable

runnable - code to run on the user-interface thread

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the runnable is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.2

See Also:

asyncExec(java.lang.Runnable)

readAndDispatch

public boolean readAndDispatch()

Reads an event from the event queue, dispatches it appropriately, and returns true if there is potentially more work to do, or false if the caller can sleep until another event is placed on the event queue.

In addition to checking the system event queue, this method also checks if any inter-thread messages (created by syncExec() or asyncExec()) are waiting to be processed, and if so handles them before returning.

Returns:

false if the caller can sleep upon return from this method

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed
• ERROR_FAILED_EXEC - if an exception occurred while running an inter-thread message

Since:

1.1

See Also:

sleep(), wake()

sleep

public boolean sleep()

Causes the user-interface thread to sleep (that is, to be put in a state where it does not consume CPU cycles) until an event is received or it is otherwise awakened.

Returns:

true if an event requiring dispatching was placed on the queue.

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.1

See Also:

wake()

wake

public void wake()

Notifies the client side to send a life cycle request as UI thread to perform UI-updates. Note that this method may be called from any thread.

Note that this only works as expected if the UICallBack mechanism is activated.

Throws:

SWTException -

• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

getSystemTray

public Tray getSystemTray()

Returns the single instance of the system tray or null when there is no system tray available for the platform.

Returns:

the system tray or null

Throws:

SWTException -

• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.4

getMenuBar

public Menu getMenuBar()

Returns the single instance of the application menu bar or null when there is no application menu bar for the platform.

Returns:

the application menu bar or null

Throws:

SWTException -

• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.4

getSystemTaskBar

public TaskBar getSystemTaskBar()

Returns the single instance of the system taskBar or null when there is no system taskBar available for the platform.

Returns:

the system taskBar or null

Throws:

SWTException -

• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.4

getSystemMenu

public Menu getSystemMenu()

Returns the single instance of the system-provided menu for the application. On platforms where no menu is provided for the application this method returns null.

Returns:

the system menu or null

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.4

getSystemColor

public Color getSystemColor(int id)

Returns the matching standard color for the given constant, which should be one of the color constants specified in class SWT. Any value other than one of the SWT color constants which is passed in will result in the color black. This color should not be free'd because it was allocated by the system, not the application.

Overrides:

getSystemColor in class Device

Parameters:

id - the color constant

Returns:

the matching color

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

See Also:

SWT

getSystemImage

public Image getSystemImage(int id)

Returns the matching standard platform image for the given constant, which should be one of the icon constants specified in class SWT. This image should not be free'd because it was allocated by the system, not the application. A value of null will be returned either if the supplied constant is not an SWT icon constant or if the platform does not define an image that corresponds to the constant.

Parameters:

id - the SWT icon constant

Returns:

the corresponding image or null

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

See Also:

SWT.ICON_ERROR, SWT.ICON_INFORMATION, SWT.ICON_QUESTION, SWT.ICON_WARNING, SWT.ICON_WORKING

getSystemCursor

public Cursor getSystemCursor(int id)

Returns the matching standard platform cursor for the given constant, which should be one of the cursor constants specified in class SWT. This cursor should not be free'd because it was allocated by the system, not the application. A value of null will be returned if the supplied constant is not an SWT cursor constant.

Parameters:

id - the SWT cursor constant

Returns:

the corresponding cursor or null

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

See Also:

SWT.CURSOR_ARROW, SWT.CURSOR_WAIT, SWT.CURSOR_CROSS, SWT.CURSOR_HELP, SWT.CURSOR_SIZEALL, SWT.CURSOR_SIZENS, SWT.CURSOR_SIZEWE, SWT.CURSOR_SIZEN, SWT.CURSOR_SIZES, SWT.CURSOR_SIZEE, SWT.CURSOR_SIZEW, SWT.CURSOR_SIZENE, SWT.CURSOR_SIZESE, SWT.CURSOR_SIZESW, SWT.CURSOR_SIZENW, SWT.CURSOR_IBEAM, SWT.CURSOR_HAND

getDoubleClickTime

public int getDoubleClickTime()

Returns the longest duration, in milliseconds, between two mouse button clicks that will be considered a double click .

Returns:

the double click time

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.2

getCursorControl

public Control getCursorControl()

Returns the control which the on-screen pointer is currently over top of, or null if it is not currently over one of the controls built by the currently running application.

Returns:

the control under the cursor or null

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

getDismissalAlignment

public int getDismissalAlignment()

Returns the button dismissal alignment, one of LEFT or RIGHT. The button dismissal alignment is the ordering that should be used when positioning the default dismissal button for a dialog. For example, in a dialog that contains an OK and CANCEL button, on platforms where the button dismissal alignment is LEFT, the button ordering should be OK/CANCEL. When button dismissal alignment is RIGHT, the button ordering should be CANCEL/OK.

Returns:

the button dismissal order

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

getHighContrast

public boolean getHighContrast()

Returns true when the high contrast mode is enabled. Otherwise, false is returned.

Note: This operation is a hint and is not supported on platforms that do not have this concept.

Returns:

the high contrast mode

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

getCursorLocation

public Point getCursorLocation()

Returns the location of the on-screen pointer relative to the top left corner of the screen.

Returns:

the cursor location

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

addFilter

public void addFilter(int eventType,
                      Listener listener)

Adds the listener to the collection of listeners who will be notified when an event of the given type occurs anywhere in a widget. The event type is one of the event constants defined in class SWT. When the event does occur, the listener is notified by sending it the handleEvent() message.

Setting the type of an event to SWT.None from within the handleEvent() method can be used to change the event type and stop subsequent Java listeners from running. Because event filters run before other listeners, event filters can both block other listeners and set arbitrary fields within an event. For this reason, event filters are both powerful and dangerous. They should generally be avoided for performance, debugging and code maintenance reasons.

Parameters:

eventType - the type of event to listen for

listener - the listener which should be notified when the event occurs

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

See Also:

Listener, SWT, removeFilter(int, org.eclipse.swt.widgets.Listener), removeListener(int, org.eclipse.swt.widgets.Listener)

removeFilter

public void removeFilter(int eventType,
                         Listener listener)

Removes the listener from the collection of listeners who will be notified when an event of the given type occurs anywhere in a widget. The event type is one of the event constants defined in class SWT.

Parameters:

eventType - the type of event to listen for

listener - the listener which should no longer be notified when the event occurs

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

See Also:

Listener, SWT, addFilter(int, org.eclipse.swt.widgets.Listener), addListener(int, org.eclipse.swt.widgets.Listener)

getData

public Object getData()

Returns the application defined, display specific data associated with the receiver, or null if it has not been set. The display specific data is a single, unnamed field that is stored with every display.

Applications may put arbitrary objects in this field. If the object stored in the display specific data needs to be notified when the display is disposed of, it is the application's responsibility to provide a disposeExec() handler which does so.

Returns:

the display specific data

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.2

See Also:

setData(Object), disposeExec(Runnable)

setData

public void setData(Object data)

Sets the application defined, display specific data associated with the receiver, to the argument. The display specific data is a single, unnamed field that is stored with every display.

Applications may put arbitrary objects in this field. If the object stored in the display specific data needs to be notified when the display is disposed of, it is the application's responsibility provide a disposeExec() handler which does so.

Parameters:

data - the new display specific data

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.2

See Also:

getData(), disposeExec(Runnable)

setData

public void setData(String key,
                    Object value)

Sets the application defined property of the receiver with the specified name to the given argument.

Applications may have associated arbitrary objects with the receiver in this fashion. If the objects stored in the properties need to be notified when the display is disposed of, it is the application's responsibility provide a disposeExec() handler which does so.

Parameters:

key - the name of the property

value - the new value for the property

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the key is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.2

See Also:

getData(String), disposeExec(Runnable)

getData

public Object getData(String key)

Returns the application defined property of the receiver with the specified name, or null if it has not been set.

Applications may have associated arbitrary objects with the receiver in this fashion. If the objects stored in the properties need to be notified when the display is disposed of, it is the application's responsibility to provide a disposeExec() handler which does so.

Parameters:

key - the name of the property

Returns:

the value of the property or null if it has not been set

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the key is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.2

See Also:

setData(String, Object), disposeExec(Runnable)

getMonitors

public Monitor[] getMonitors()

Returns an array of monitors attached to the device.

Returns:

the array of monitors

Since:

1.2

getPrimaryMonitor

public Monitor getPrimaryMonitor()

Returns the primary monitor for that device.

Returns:

the primary monitor

Since:

1.2

getAppName

public static String getAppName()

Returns the application name.

Returns:

the application name

Since:

1.3

See Also:

setAppName(String)

getAppVersion

public static String getAppVersion()

Returns the application version.

Returns:

the application version

Since:

1.3

See Also:

setAppVersion(String)

setAppName

public static void setAppName(String name)

Sets the application name to the argument.

Specifying null for the name clears it.

Parameters:

name - the new app name or null

Since:

1.3

setAppVersion

public static void setAppVersion(String version)

Sets the application version to the argument.

Parameters:

version - the new app version

Since:

1.3

update

public void update()

Forces all outstanding paint requests for the display to be processed before this method returns.

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

See Also:

Control.update()

beep

public void beep()

Causes the system hardware to emit a short sound (if it supports this capability).

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_DEVICE_DISPOSED - if the receiver has been disposed

Since:

1.3

getTouchEnabled

public boolean getTouchEnabled()

Returns true if a touch-aware input device is attached to the system, enabled, and ready for use.

Since:

1.4

checkDevice

protected void checkDevice()

Description copied from class: Device

Throws an SWTException if the receiver can not be accessed by the caller. This may include both checks on the state of the receiver and more generally on the entire execution context. This method should be called by device implementors to enforce the standard SWT invariants.

Currently, it is an error to invoke any method (other than isDisposed() and dispose()) on a device that has had its dispose() method called.

In future releases of SWT, there may be more or fewer error checks and exceptions may be thrown for different reasons.

Overrides:

checkDevice in class Device