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Eclipse Platform
Release 3.0

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org.eclipse.jface.window
Class Window

java.lang.Object
  org.eclipse.jface.window.Window

Direct Known Subclasses:

ApplicationWindow, Dialog

public abstract class Window

extends Object

A JFace window is an object that has no visual representation (no widgets) until it is told to open.

Creating a window involves the following steps:

• creating an instance of a concrete subclass of Window
• creating the window's shell and widget tree by calling create (optional)
• assigning the window to a window manager using WindowManager.add (optional)
• opening the window by calling open

Opening the window will create its shell and widget tree if they have not already been created. When the window is closed, the shell and widget tree are disposed of and are no longer referenced, and the window is automatically removed from its window manager. A window may be reopened.

The JFace window framework (this package) consists of this class, Window, the abstract base of all windows, and one concrete window classes (ApplicationWindow) which may also be subclassed. Clients may define additional window subclasses as required.

The Window class provides the following methods which subclasses may override:

• close - extend to free other SWT resources
• configureShell - extend or reimplement to set shell properties before window opens
• createContents - extend or reimplement to create controls before window opens
• getInitialSize - reimplement to give the initial size for the shell
• getInitialLocation - reimplement to give the initial location for the shell
• getShellListener - extend or reimplement to receive shell events
• getToolTipText - reimplement to add tool tips
• handleFontChange - reimplement to respond to font changes
• handleShellCloseEvent - extend or reimplement to handle shell closings

Nested Class Summary

static interface

Window.IExceptionHandler This interface defines a Exception Handler which can be set as a global handler and will be called if an exception happens in the event loop.

Field Summary

static int	CANCEL Standard return code constant (value 1) indicating that the window was canceled.
static int	OK Standard return code constant (value 0) indicating that the window was opened.

Constructor Summary

protected

Window(Shell parentShell) Creates a window instance, whose shell will be created under the given parent shell.

Method Summary

protected boolean	canHandleShellCloseEvent() Determines if the window should handle the close event or do nothing.
boolean	close() Closes this window, disposes its shell, and removes this window from its window manager (if it has one).
protected void	configureShell(Shell newShell) Configures the given shell in preparation for opening this window in it.
protected void	constrainShellSize() Constrain the shell size to be no larger than the display bounds.
void	create() Creates this window's widgetry in a new top-level shell.
protected Control	createContents(Composite parent) Creates and returns this window's contents.
protected Shell	createShell() Creates and returns this window's shell.
protected Rectangle	getConstrainedShellBounds(Rectangle preferredSize) Given the desired position of the window, this method returns an adjusted position such that the window is no larger than its monitor, and does not extend beyond the edge of the monitor.
protected Control	getContents() Returns the top level control for this window.
static Image	getDefaultImage() Returns the default image.
static Image[]	getDefaultImages() Returns the array of default images to use for newly opened windows.
protected Point	getInitialLocation(Point initialSize) Returns the initial location to use for the shell.
protected Point	getInitialSize() Returns the initial size to use for the shell.
protected Layout	getLayout() Creates the layout for the shell.
protected Shell	getParentShell() Returns parent shell, under which this window's shell is created.
int	getReturnCode() Returns this window's return code.
Shell	getShell() Returns this window's shell.
protected ShellListener	getShellListener() Returns a shell listener.
protected int	getShellStyle() Returns the shell style bits.
WindowManager	getWindowManager() Returns the window manager of this window.
protected void	handleFontChange(PropertyChangeEvent event) Notifies of a font property change.
protected void	handleShellCloseEvent() Notifies that the window's close button was pressed, the close menu was selected, or the ESCAPE key pressed.
protected void	initializeBounds() Initializes the location and size of this window's SWT shell after it has been created.
int	open() Opens this window, creating it first if it has not yet been created.
void	setBlockOnOpen(boolean shouldBlock) Sets whether the open method should block until the window closes.
static void	setDefaultImage(Image image) Sets the default image.
static void	setDefaultImages(Image[] images) Sets the array of default images to use for newly opened windows.
static void	setExceptionHandler(Window.IExceptionHandler handler) Sets the exception handler for this application.
protected void	setReturnCode(int code) Sets this window's return code.
protected void	setShellStyle(int newShellStyle) Sets the shell style bits.
void	setWindowManager(WindowManager manager) Sets the window manager of this window.

Methods inherited from class java.lang.Object

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

Field Detail

OK

public static final int OK

Standard return code constant (value 0) indicating that the window was opened.

See Also:

open(), Constant Field Values

CANCEL

public static final int CANCEL

Standard return code constant (value 1) indicating that the window was canceled.

See Also:

open(), Constant Field Values

Constructor Detail

Window

protected Window(Shell parentShell)

Creates a window instance, whose shell will be created under the given parent shell. Note that the window will have no visual representation until it is told to open. By default, open does not block.

Parameters:

parentShell - the parent shell, or null to create a top-level shell

See Also:

setBlockOnOpen(boolean)

Method Detail

canHandleShellCloseEvent

protected boolean canHandleShellCloseEvent()

Determines if the window should handle the close event or do nothing.

The default implementation of this framework method returns true, which will allow the handleShellCloseEvent method to be called. Subclasses may extend or reimplement.

Returns:

whether the window should handle the close event.

close

public boolean close()

Closes this window, disposes its shell, and removes this window from its window manager (if it has one).

This framework method may be extended (super.close must be called).

Returns:

true if the window is (or was already) closed, and false if it is still open

configureShell

protected void configureShell(Shell newShell)

Configures the given shell in preparation for opening this window in it.

The default implementation of this framework method sets the shell's image and gives it a grid layout. Subclasses may extend or reimplement.

Parameters:

newShell - the shell

getLayout

protected Layout getLayout()

Creates the layout for the shell. The layout created here will be attached to the composite passed into createContents. The default implementation returns a GridLayout with no margins. Subclasses that change the layout type by overriding this method should also override createContents.

A return value of null indicates that no layout should be attached to the composite. In this case, the layout may be attached within createContents.

Returns:

a newly created Layout or null if no layout should be attached.

Since:

3.0

constrainShellSize

protected void constrainShellSize()

Constrain the shell size to be no larger than the display bounds.

Since:

2.0

create

public void create()

Creates this window's widgetry in a new top-level shell.

The default implementation of this framework method creates this window's shell (by calling createShell), and its controls (by calling createContents), then initializes this window's shell bounds (by calling initializeBounds).

createContents

protected Control createContents(Composite parent)

Creates and returns this window's contents. Subclasses may attach any number of children to the parent. As a convenience, the return value of this method will be remembered and returned by subsequent calls to getControl(). Subclasses may modify the parent's layout if they overload getLayout() to return null.

It is common practise to create and return a single composite that contains the entire window contents.

The default implementation of this framework method creates an instance of Composite. Subclasses may override.

Parameters:

parent - the parent composite for the controls in this window. The type of layout used is determined by getLayout()

Returns:

the control that will be returned by subsequent calls to getControl()

createShell

protected final Shell createShell()

Creates and returns this window's shell.

The default implementation of this framework method creates a new shell and configures it using configureShell. Rather than override this method, subclasses should instead override configureShell.

Returns:

the shell

getContents

protected Control getContents()

Returns the top level control for this window. The parent of this control is the shell.

Returns:

the top level control, or null if this window's control has not been created yet

getDefaultImage

public static Image getDefaultImage()

Returns the default image. This is the image that will be used for windows that have no shell image at the time they are opened. There is no default image unless one is installed via setDefaultImage.

Returns:

the default image, or null if none

See Also:

setDefaultImage(org.eclipse.swt.graphics.Image)

getDefaultImages

public static Image[] getDefaultImages()

Returns the array of default images to use for newly opened windows. It is expected that the array will contain the same icon rendered at different resolutions.

Returns:

the array of images to be used when a new window is opened

Since:

3.0

See Also:

Decorations.setImages(org.eclipse.swt.graphics.Image[]), setDefaultImages(org.eclipse.swt.graphics.Image[])

getInitialLocation

protected Point getInitialLocation(Point initialSize)

Returns the initial location to use for the shell. The default implementation centers the shell horizontally (1/2 of the difference to the left and 1/2 to the right) and vertically (1/3 above and 2/3 below) relative to the parent shell, or display bounds if there is no parent shell.

Parameters:

initialSize - the initial size of the shell, as returned by getInitialSize.

Returns:

the initial location of the shell

getInitialSize

protected Point getInitialSize()

Returns the initial size to use for the shell. The default implementation returns the preferred size of the shell, using Shell.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).

Returns:

the initial size of the shell

getParentShell

protected Shell getParentShell()

Returns parent shell, under which this window's shell is created.

Returns:

the parent shell, or null if there is no parent shell

getReturnCode

public int getReturnCode()

Returns this window's return code. A window's return codes are window-specific, although two standard return codes are predefined: OK and CANCEL.

Returns:

the return code

getShell

public Shell getShell()

Returns this window's shell.

Returns:

this window's shell, or null if this window's shell has not been created yet

getShellListener

protected ShellListener getShellListener()

Returns a shell listener. This shell listener gets registered with this window's shell.

The default implementation of this framework method returns a new listener that makes this window the active window for its window manager (if it has one) when the shell is activated, and calls the framework method handleShellCloseEvent when the shell is closed. Subclasses may extend or reimplement.

Returns:

a shell listener

getShellStyle

protected int getShellStyle()

Returns the shell style bits.

The default value is SWT.CLOSE|SWT.MIN|SWT.MAX|SWT.RESIZE. Subclassers should call setShellStyle to change this value, rather than overriding this method.

Returns:

the shell style bits

getWindowManager

public WindowManager getWindowManager()

Returns the window manager of this window.

Returns:

the WindowManager, or null if none

handleFontChange

protected void handleFontChange(PropertyChangeEvent event)

Notifies of a font property change.

The default implementation of this framework method does nothing. Subclasses may reimplement.

Parameters:

event - the property change event detailing what changed

handleShellCloseEvent

protected void handleShellCloseEvent()

Notifies that the window's close button was pressed, the close menu was selected, or the ESCAPE key pressed.

The default implementation of this framework method sets the window's return code to CANCEL and closes the window using close. Subclasses may extend or reimplement.

initializeBounds

protected void initializeBounds()

Initializes the location and size of this window's SWT shell after it has been created.

This framework method is called by the create framework method. The default implementation calls getInitialSize and getInitialLocation and passes the results to Shell.setBounds. This is only done if the bounds of the shell have not already been modified. Subclasses may extend or reimplement.

open

public int open()

Opens this window, creating it first if it has not yet been created.

If this window has been configured to block on open (setBlockOnOpen), this method waits until the window is closed by the end user, and then it returns the window's return code; otherwise, this method returns immediately. A window's return codes are window-specific, although two standard return codes are predefined: OK and CANCEL.

Returns:

the return code

See Also:

create()

setBlockOnOpen

public void setBlockOnOpen(boolean shouldBlock)

Sets whether the open method should block until the window closes.

Parameters:

shouldBlock - true if the open method should not return until the window closes, and false if the open method should return immediately

setDefaultImage

public static void setDefaultImage(Image image)

Sets the default image. This is the image that will be used for windows that have no shell image at the time they are opened. There is no default image unless one is installed via this method.

Parameters:

image - the default image, or null if none

setDefaultImages

public static void setDefaultImages(Image[] images)

Sets the array of default images to use for newly opened windows. It is expected that the array will contain the same icon rendered at different resolutions.

Parameters:

images - the array of images to be used when this window is opened

Since:

3.0

See Also:

Decorations.setImages(org.eclipse.swt.graphics.Image[])

setReturnCode

protected void setReturnCode(int code)

Sets this window's return code. The return code is automatically returned by open if block on open is enabled. For non-blocking opens, the return code needs to be retrieved manually using getReturnCode.

Parameters:

code - the return code

getConstrainedShellBounds

protected Rectangle getConstrainedShellBounds(Rectangle preferredSize)

Given the desired position of the window, this method returns an adjusted position such that the window is no larger than its monitor, and does not extend beyond the edge of the monitor. This is used for computing the initial window position, and subclasses can use this as a utility method if they want to limit the region in which the window may be moved.

Parameters:

preferredSize - the preferred position of the window

Returns:

a rectangle as close as possible to preferredSize that does not extend outside the monitor

Since:

3.0

setShellStyle

protected void setShellStyle(int newShellStyle)

Sets the shell style bits. This method has no effect after the shell is created.

The shell style bits are used by the framework method createShell when creating this window's shell.

Parameters:

newShellStyle - the new shell style bits

setWindowManager

public void setWindowManager(WindowManager manager)

Sets the window manager of this window.

Note that this method is used by WindowManager to maintain a backpointer. Clients must not call the method directly.

Parameters:

manager - the window manager, or null if none

setExceptionHandler

public static void setExceptionHandler(Window.IExceptionHandler handler)

Sets the exception handler for this application.

Note that only one handler may be set. Other calls to this method will be ignored.

Parameters:

handler - the exception handler for the application.