Class Display

  • All Implemented Interfaces:
    Drawable

    public class Display
    extends Device
    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, OpenDocument, Settings, Skin

    IMPORTANT: This class is not intended to be subclassed.

    See Also:
    syncExec(java.lang.Runnable), asyncExec(java.lang.Runnable), wake(), readAndDispatch(), sleep(), Device.dispose(), Display snippets, Sample code and further information
    Restriction:
    This class is not intended to be subclassed by clients.
    • Field Summary

      Fields 
      Modifier and Type Field Description
      org.eclipse.swt.internal.win32.MSG msg
      the handle to the OS message queue (Warning: This field is platform dependent)
    • Constructor Summary

      Constructors 
      Constructor Description
      Display()
      Constructs a new instance of this class.
      Display​(DeviceData data)
      Constructs a new instance of this class using the parameter.
    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      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.
      protected void checkSubclass()
      Checks that this class can be subclassed.
      void close()
      Requests that the connection between SWT and the underlying operating system be closed.
      protected void create​(DeviceData data)
      Creates the device in the operating system.
      protected void destroy()
      Destroys the device in the operating system and releases the device's handle.
      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.
      Widget findWidget​(long handle)
      Given the operating system handle for a widget, returns the instance of the Widget subclass which represents it in the currently running application, if such exists, or null if no matching widget can be found.
      Widget findWidget​(long handle, long id)
      Given the operating system handle for a widget, and widget-specific id, returns the instance of the Widget subclass which represents the handle/id pair in the currently running application, if such exists, or null if no matching widget can be found.
      Widget findWidget​(Widget widget, long id)
      Given a widget and a widget-specific id, returns the instance of the Widget subclass which represents the widget/id pair in the currently running application, if such exists, or null if no matching widget can be found.
      Shell getActiveShell()
      Returns the currently active Shell, or null if no shell belonging to the currently running application is active.
      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.
      Rectangle getClientArea()
      Returns a rectangle which describes the area of the receiver which is capable of displaying data.
      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.
      Point[] getCursorSizes()
      Returns an array containing the recommended cursor sizes.
      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.
      protected int getDeviceZoom()
      Gets the scaling factor from the device and calculates the zoom level.
      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 by the underlying operating system.
      Consumer<Error> getErrorHandler()
      Returns the current exception handler.
      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.
      int getIconDepth()
      Returns the maximum allowed depth of icons on this display, in bits per pixel.
      Point[] getIconSizes()
      Returns an array containing the recommended icon sizes.
      Menu getMenuBar()
      Returns the single instance of the application menu bar, or null if 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.
      Consumer<RuntimeException> getRuntimeExceptionHandler()
      Returns the current exception handler.
      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.
      Font getSystemFont()
      Returns a reasonable font for applications to use.
      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, or null on platforms where no menu is provided 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 a boolean indicating whether a touch-aware input device is attached to the system and is ready for use.
      protected void init()
      Initializes any internal resources needed by the device.
      void internal_dispose_GC​(long hDC, GCData data)
      Invokes platform specific functionality to dispose a GC handle.
      long internal_new_GC​(GCData data)
      Invokes platform specific functionality to allocate a new GC handle.
      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 post​(Event event)
      Generate a low level system event.
      boolean readAndDispatch()
      Reads an event from the operating system's 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 back to the operating system and clears all fields except the device handle.
      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.
      void sendPostExternalEventDispatchEvent()
      Sends a SWT.PostExternalEventDispatch event.
      void sendPreExternalEventDispatchEvent()
      Sends a SWT.PreExternalEventDispatch event.
      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 setCursorLocation​(int x, int y)
      Sets the location of the on-screen pointer relative to the top left corner of the screen.
      void setCursorLocation​(Point point)
      Sets the location of the on-screen pointer relative to the top left corner of the screen.
      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 setErrorHandler​(Consumer<Error> errorHandler)
      Sets a callback that will be invoked whenever an error is thrown by a listener or external callback function.
      void setRuntimeExceptionHandler​(Consumer<RuntimeException> runtimeExceptionHandler)
      Sets a callback that will be invoked whenever an exception is thrown by a listener or external callback function.
      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()
      If the receiver's user-interface thread was sleeping, causes it to be awakened and start running again.
    • Field Detail

      • msg

        public org.eclipse.swt.internal.win32.MSG msg
        the handle to the OS message queue (Warning: This field is platform dependent)

        IMPORTANT: This field is not part of the SWT public API. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms and should never be accessed from application code.

        Restriction:
        This field is not intended to be referenced by clients.
    • 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
      • Display

        public Display​(DeviceData data)
        Constructs a new instance of this class using the parameter.
        Parameters:
        data - the device data
    • Method Detail

      • 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
        Since:
        3.0
        See Also:
        Listener, SWT, removeFilter(int, org.eclipse.swt.widgets.Listener), removeListener(int, org.eclipse.swt.widgets.Listener)
      • 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:
        2.0
        See Also:
        Listener, SWT, removeListener(int, org.eclipse.swt.widgets.Listener)
      • 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. 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)
      • 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
      • checkSubclass

        protected void checkSubclass()
        Checks that this class can be subclassed.

        IMPORTANT: See the comment in Widget.checkSubclass().

        Throws:
        SWTException -
        • ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass
        See Also:
        Widget.checkSubclass()
      • 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
      • 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:
        2.0
        See Also:
        Device.dispose()
      • create

        protected void create​(DeviceData data)
        Creates the device in the operating system. If the device does not have a handle, this method may do nothing depending on the device.

        This method is called before init.

        Overrides:
        create in class Device
        Parameters:
        data - the DeviceData which describes the receiver
        See Also:
        init()
      • destroy

        protected void destroy()
        Destroys the device in the operating system and releases the device's handle. If the device does not have a handle, this method may do nothing depending on the device.

        This method is called after release.

        Overrides:
        destroy in class Device
        See Also:
        Device.dispose(), release()
      • 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
      • findWidget

        public Widget findWidget​(long handle)
        Given the operating system handle for a widget, returns the instance of the Widget subclass which represents it in the currently running application, if such exists, or null if no matching widget can be found.

        IMPORTANT: This method should not be called from application code. The arguments are platform-specific.

        Parameters:
        handle - the handle for the widget
        Returns:
        the SWT widget that the handle represents
        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
        Restriction:
        This method is not intended to be referenced by clients.
      • findWidget

        public Widget findWidget​(long handle,
                                 long id)
        Given the operating system handle for a widget, and widget-specific id, returns the instance of the Widget subclass which represents the handle/id pair in the currently running application, if such exists, or null if no matching widget can be found.

        IMPORTANT: This method should not be called from application code. The arguments are platform-specific.

        Parameters:
        handle - the handle for the widget
        id - the id for the subwidget (usually an item)
        Returns:
        the SWT widget that the handle/id pair represents
        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:
        3.1
        Restriction:
        This method is not intended to be referenced by clients.
      • findWidget

        public Widget findWidget​(Widget widget,
                                 long id)
        Given a widget and a widget-specific id, returns the instance of the Widget subclass which represents the widget/id pair in the currently running application, if such exists, or null if no matching widget can be found.
        Parameters:
        widget - the widget
        id - the id for the subwidget (usually an item)
        Returns:
        the SWT subwidget (usually an item) that the widget/id pair represents
        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:
        3.3
        Restriction:
        This method is not intended to be referenced by clients.
      • 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
      • 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
      • getMenuBar

        public Menu getMenuBar()
        Returns the single instance of the application menu bar, or null if 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:
        3.7
      • getBounds

        public Rectangle getBounds()
        Returns a rectangle describing the receiver's size and location. Note that on multi-monitor systems the origin can be negative.
        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
      • 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
      • getClientArea

        public Rectangle getClientArea()
        Returns a rectangle which describes the area of the receiver which is capable of displaying data.
        Overrides:
        getClientArea in class Device
        Returns:
        the client area
        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:
        getBounds()
      • 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
      • 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
      • getCursorSizes

        public Point[] getCursorSizes()
        Returns an array containing the recommended cursor sizes.
        Returns:
        the array of cursor sizes
        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:
        3.0
      • getDefault

        public static Display getDefault()
        Returns the default display. One is created (making the thread that invokes this method its user-interface thread) if it did not already exist.
        Returns:
        the default display
      • getDeviceZoom

        protected int getDeviceZoom()
        Description copied from class: Device
        Gets the scaling factor from the device and calculates the zoom level.
        Overrides:
        getDeviceZoom in class Device
        Returns:
        zoom in percentage
        Since:
        3.108
      • 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
        See Also:
        setData(String, Object), disposeExec(Runnable)
      • 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
        See Also:
        setData(Object), disposeExec(Runnable)
      • 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:
        2.1
      • getDoubleClickTime

        public int getDoubleClickTime()
        Returns the longest duration, in milliseconds, between two mouse button clicks that will be considered a double click by the underlying operating system.
        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
      • 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 focus control 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
      • 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:
        3.0
      • getIconDepth

        public int getIconDepth()
        Returns the maximum allowed depth of icons on this display, in bits per pixel. On some platforms, this may be different than the actual depth of the display.
        Returns:
        the maximum icon depth
        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:
        Device.getDepth()
      • getIconSizes

        public Point[] getIconSizes()
        Returns an array containing the recommended icon sizes.
        Returns:
        the array of icon sizes
        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:
        3.0
        See Also:
        Decorations.setImages(Image[])
      • getMonitors

        public Monitor[] getMonitors()
        Returns an array of monitors attached to the device.
        Returns:
        the array of monitors
        Since:
        3.0
      • getPrimaryMonitor

        public Monitor getPrimaryMonitor()
        Returns the primary monitor for that device.
        Returns:
        the primary monitor
        Since:
        3.0
      • 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
      • 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:
        3.4
      • 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
      • 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
      • getSystemFont

        public Font getSystemFont()
        Returns a reasonable font for applications to use. On some platforms, this will match the "default font" or "system font" if such can be found. This font should not be free'd because it was allocated by the system, not the application.

        Typically, applications which want the default look should simply not set the font on the widgets they create. Widgets are always created with the correct default font for the class of user-interface component they represent.

        Overrides:
        getSystemFont in class Device
        Returns:
        a font
        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
      • 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
        Since:
        3.0
        See Also:
        SWT.ICON_ERROR, SWT.ICON_INFORMATION, SWT.ICON_QUESTION, SWT.ICON_WARNING, SWT.ICON_WORKING
      • getSystemMenu

        public Menu getSystemMenu()
        Returns the single instance of the system-provided menu for the application, or null on platforms where no menu is provided for the application.
        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:
        3.7
      • 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:
        3.6
      • 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:
        3.0
      • getThread

        public Thread getThread()
        Returns the user-interface thread for the receiver.
        Returns:
        the receiver's user-interface thread
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
      • getTouchEnabled

        public boolean getTouchEnabled()
        Returns a boolean indicating whether a touch-aware input device is attached to the system and is ready for use.
        Returns:
        true if a touch-aware input device is detected, or false otherwise
        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:
        3.7
      • internal_new_GC

        public long internal_new_GC​(GCData data)
        Invokes platform specific functionality to allocate a new GC handle.

        IMPORTANT: This method is not part of the public API for Display. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

        Specified by:
        internal_new_GC in interface Drawable
        Specified by:
        internal_new_GC in class Device
        Parameters:
        data - the platform specific GC data
        Returns:
        the platform specific GC handle
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
        SWTError -
        • ERROR_NO_HANDLES if a handle could not be obtained for gc creation
        Restriction:
        This method is not intended to be referenced by clients.
      • internal_dispose_GC

        public void internal_dispose_GC​(long hDC,
                                        GCData data)
        Invokes platform specific functionality to dispose a GC handle.

        IMPORTANT: This method is not part of the public API for Display. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

        Specified by:
        internal_dispose_GC in interface Drawable
        Specified by:
        internal_dispose_GC in class Device
        Parameters:
        hDC - the platform specific GC handle
        data - the platform specific GC data
        Restriction:
        This method is not intended to be referenced by clients.
      • 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
        Since:
        2.1.2
      • 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
        Since:
        2.1.2
      • 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
        Since:
        2.1.2
      • 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
        Since:
        2.1.2
      • post

        public boolean post​(Event event)
        Generate a low level system event. post is used to generate low level keyboard and mouse events. The intent is to enable automated UI testing by simulating the input from the user. Most SWT applications should never need to call this method.

        Note that this operation can fail when the operating system fails to generate the event for any reason. For example, this can happen when there is no such key or mouse button or when the system event queue is full.

        Event Types:

        KeyDown, KeyUp

        The following fields in the Event apply:

        • (in) type KeyDown or KeyUp

        Either one of:

        • (in) character a character that corresponds to a keyboard key
        • (in) keyCode the key code of the key that was typed, as defined by the key code constants in class SWT

        Optional (on some platforms):

        • (in) stateMask the state of the keyboard modifier, as defined by the key code constants in class SWT

        MouseDown, MouseUp

        The following fields in the Event apply:

        • (in) type MouseDown or MouseUp
        • (in) button the button that is pressed or released

        MouseMove

        The following fields in the Event apply:

        • (in) type MouseMove
        • (in) x the x coordinate to move the mouse pointer to in screen coordinates
        • (in) y the y coordinate to move the mouse pointer to in screen coordinates

        MouseWheel

        The following fields in the Event apply:

        • (in) type MouseWheel
        • (in) detail either SWT.SCROLL_LINE or SWT.SCROLL_PAGE
        • (in) count the number of lines or pages to scroll
        Parameters:
        event - the event to be generated
        Returns:
        true if the event was generated or false otherwise
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the event is null
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
        Since:
        3.0
      • readAndDispatch

        public boolean readAndDispatch()
        Reads an event from the operating system's 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
        See Also:
        sleep(), wake()
      • release

        protected void release()
        Releases any internal resources back to the operating system and clears all fields except the device handle.

        Disposes all shells which are currently open on the display. After this method has been invoked, all related related shells will answer true when sent the message isDisposed().

        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.
        Overrides:
        release in class Device
        See Also:
        Device.dispose(), destroy()
      • 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:
        2.0
        See Also:
        Listener, SWT, addListener(int, org.eclipse.swt.widgets.Listener)
      • sendPreExternalEventDispatchEvent

        public void sendPreExternalEventDispatchEvent()
        Sends a SWT.PreExternalEventDispatch event.
        Restriction:
        This method is not intended to be referenced by clients.
      • sendPostExternalEventDispatchEvent

        public void sendPostExternalEventDispatchEvent()
        Sends a SWT.PostExternalEventDispatch event.
        Restriction:
        This method is not intended to be referenced by clients.
      • setCursorLocation

        public void setCursorLocation​(int x,
                                      int y)
        Sets the location of the on-screen pointer relative to the top left corner of the screen. Note: It is typically considered bad practice for a program to move the on-screen pointer location.
        Parameters:
        x - the new x coordinate for the cursor
        y - the new y coordinate for 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
        Since:
        2.1
      • setCursorLocation

        public void setCursorLocation​(Point point)
        Sets the location of the on-screen pointer relative to the top left corner of the screen. Note: It is typically considered bad practice for a program to move the on-screen pointer location.
        Parameters:
        point - new position
        Throws:
        SWTException -
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        • ERROR_NULL_ARGUMENT - if the point is null
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
        Since:
        2.0
      • 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
        See Also:
        getData(String), 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
        See Also:
        getData(), disposeExec(Runnable)
      • getAppName

        public static String getAppName()
        Returns the application name.
        Returns:
        the application name
        Since:
        3.6
        See Also:
        setAppName(String)
      • getAppVersion

        public static String getAppVersion()
        Returns the application version.
        Returns:
        the application version
        Since:
        3.6
        See Also:
        setAppVersion(String)
      • setAppName

        public static void setAppName​(String name)
        Sets the application name to the argument.

        The application name can be used in several ways, depending on the platform and tools being used. Accessibility tools could ask for the application name. On Windows, if the application name is set to any value other than "SWT" (case insensitive), it is used to set the application user model ID which is used by the OS for taskbar grouping.

        Parameters:
        name - the new app name or null
        See Also:
        AppUserModelID (Windows)

        Specifying null for the name clears it.

      • setAppVersion

        public static void setAppVersion​(String version)
        Sets the application version to the argument.
        Parameters:
        version - the new app version
        Since:
        3.6
      • 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
      • setRuntimeExceptionHandler

        public final void setRuntimeExceptionHandler​(Consumer<RuntimeException> runtimeExceptionHandler)
        Sets a callback that will be invoked whenever an exception is thrown by a listener or external callback function. The application may use this to set a global exception handling policy: the most common policies are either to log and discard the exception or to re-throw the exception.

        The default SWT error handling policy is to rethrow exceptions.

        Parameters:
        runtimeExceptionHandler - new exception handler to be registered.
        Since:
        3.106
      • getRuntimeExceptionHandler

        public final Consumer<RuntimeException> getRuntimeExceptionHandler()
        Returns the current exception handler. It will receive all exceptions thrown by listeners and external callbacks in this display. If code wishes to temporarily replace the exception handler (for example, during a unit test), it is common practice to invoke this method prior to replacing the exception handler so that the old handler may be restored afterward.
        Returns:
        the current exception handler. Never null.
        Since:
        3.106
      • setErrorHandler

        public final void setErrorHandler​(Consumer<Error> errorHandler)
        Sets a callback that will be invoked whenever an error is thrown by a listener or external callback function. The application may use this to set a global exception handling policy: the most common policies are either to log and discard the exception or to re-throw the exception.

        The default SWT error handling policy is to rethrow exceptions.

        Parameters:
        errorHandler - new error handler to be registered.
        Since:
        3.106
      • getErrorHandler

        public final Consumer<Error> getErrorHandler()
        Returns the current exception handler. It will receive all errors thrown by listeners and external callbacks in this display. If code wishes to temporarily replace the error handler (for example, during a unit test), it is common practice to invoke this method prior to replacing the error handler so that the old handler may be restored afterward.
        Returns:
        the current error handler. Never null.
        Since:
        3.106
      • 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
        See Also:
        wake()
      • 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. 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 occurred 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
        See Also:
        asyncExec(java.lang.Runnable)
      • 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
        See Also:
        Control.update()
      • wake

        public void wake()
        If the receiver's user-interface thread was sleeping, causes it to be awakened and start running again. Note that this method may be called from any thread.
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
        See Also:
        sleep()