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Class java.awt.Toolkit

java.lang.Object
    |
    +----java.awt.Toolkit

public abstract class Toolkit

extends Object

Most applications should not call any of the methods in this class directly. The methods defined by Toolkit are the "glue" that joins the platform-independent classes in the java.awt package with their counterparts in java.awt.peer. Some methods defined by Toolkit query the native operating system directly.

Since:

JDK1.0

Toolkit()

beep()

Emits an audio beep.

checkImage(Image, int, int, ImageObserver)

Indicates the construction status of a specified image that is being prepared for display.

createButton(Button)

Creates this toolkit's implementation of Button using the specified peer interface.

createCanvas(Canvas)

Creates this toolkit's implementation of Canvas using the specified peer interface.

createCheckbox(Checkbox)

Creates this toolkit's implementation of Checkbox using the specified peer interface.

createCheckboxMenuItem(CheckboxMenuItem)

Creates this toolkit's implementation of CheckboxMenuItem using the specified peer interface.

createChoice(Choice)

Creates this toolkit's implementation of Choice using the specified peer interface.

createComponent(Component)

Creates a peer for a component or container.

createCustomCursor(Image, Point, String)

Creates a new custom cursor object.

createDialog(Dialog)

Creates this toolkit's implementation of Dialog using the specified peer interface.

createDragSourceContextPeer(DragSource, Component)

create the peer for a DragSourceContext

createFileDialog(FileDialog)

Creates this toolkit's implementation of FileDialog using the specified peer interface.

createFrame(Frame)

Creates this toolkit's implementation of Frame using the specified peer interface.

createImage(byte[])

Creates an image which decodes the image stored in the specified byte array.

createImage(byte[], int, int)

Creates an image which decodes the image stored in the specified byte array, and at the specified offset and length.

createImage(ImageProducer)

Creates an image with the specified image producer.

createLabel(Label)

Creates this toolkit's implementation of Label using the specified peer interface.

createList(List)

Creates this toolkit's implementation of List using the specified peer interface.

createMenu(Menu)

Creates this toolkit's implementation of Menu using the specified peer interface.

createMenuBar(MenuBar)

Creates this toolkit's implementation of MenuBar using the specified peer interface.

createMenuItem(MenuItem)

Creates this toolkit's implementation of MenuItem using the specified peer interface.

createPanel(Panel)

Creates this toolkit's implementation of Panel using the specified peer interface.

createPopupMenu(PopupMenu)

Creates this toolkit's implementation of PopupMenu using the specified peer interface.

createScrollbar(Scrollbar)

Creates this toolkit's implementation of Scrollbar using the specified peer interface.

createScrollPane(ScrollPane)

Creates this toolkit's implementation of ScrollPane using the specified peer interface.

createTextArea(TextArea)

Creates this toolkit's implementation of TextArea using the specified peer interface.

createTextField(TextField)

Creates this toolkit's implementation of TextField using the specified peer interface.

createWindow(Window)

Creates this toolkit's implementation of Window using the specified peer interface.

getBestCursorSize(int, int)

Returns the supported cursor dimension which is closest to the desired sizes.

getColorModel()

Determines the color model of this toolkit's screen.

getDefaultToolkit()

Gets the default toolkit.

getFontList()

Returns the names of the available fonts in this toolkit.

For 1.1, the following font names are deprecated (the replacement name follows):

• TimesRoman (use Serif)
• Helvetica (use SansSerif)
• Courier (use Monospaced)

The ZapfDingbats font is also deprecated in 1.1, but only as a separate fontname.

getFontMetrics(Font)

Gets the screen metrics of the font.

getFontPeer(String, int)

Creates this toolkit's implementation of Font using the specified peer interface.

getImage(String)

Returns an image which gets pixel data from the specified file.

getImage(URL)

Returns an image which gets pixel data from the specified URL.

getMaximumCursorColors()

Returns the maximum number of colors the Toolkit supports in a custom cursor palette.

Note: if an image is used which has more colors in its palette than the supported maximum, the Toolkit implementation will attempt to flatten the palette to the maximum.

getMenuShortcutKeyMask()

Determines which modifier key is the appropriate accelerator key for menu shortcuts.

getNativeContainer(Component)

Give native peers the ability to query the native container given a native component (eg the direct parent may be lightweight).

getPrintJob(Frame, String, Properties)

Gets a PrintJob object which is the result of initiating a print operation on the toolkit's platform.

getProperty(String, String)

Gets a property with the specified key and default.

getScreenResolution()

Returns the screen resolution in dots-per-inch.

getScreenSize()

Gets the size of the screen.

getSystemClipboard()

Gets an instance of the system clipboard which interfaces with clipboard facilities provided by the native platform.

getSystemEventQueue()

Get the application's or applet's EventQueue instance.

getSystemEventQueueImpl()

hasSetupPage()

Returns true if this Toolkit supports a Page Setup dialog for allowing a user to modify a PageFormat in the setupPage() method.

loadSystemColors(int[])

Fills in the integer array that is supplied as an argument with the current system color values.

prepareImage(Image, int, int, ImageObserver)

Prepares an image for rendering.

setupPage(PageFormat)

Display a dialog to the user allowing the modification of a PageFormat instance.

sync()

Synchronizes this toolkit's graphics state.

public Toolkit()

protected abstract ButtonPeer createButton(Button target)

Creates this toolkit's implementation of Button using the specified peer interface.

Parameters:

target - the button to be implemented.

Returns:

this toolkit's implementation of Button.

See Also:

Button, java.awt.peer.ButtonPeer

protected abstract TextFieldPeer createTextField(TextField target)

Creates this toolkit's implementation of TextField using the specified peer interface.

Parameters:

target - the text field to be implemented.

Returns:

this toolkit's implementation of TextField.

See Also:

TextField, java.awt.peer.TextFieldPeer

protected abstract LabelPeer createLabel(Label target)

Creates this toolkit's implementation of Label using the specified peer interface.

Parameters:

target - the label to be implemented.

Returns:

this toolkit's implementation of Label.

See Also:

Label, java.awt.peer.LabelPeer

protected abstract ListPeer createList(List target)

Creates this toolkit's implementation of List using the specified peer interface.

Parameters:

target - the list to be implemented.

Returns:

this toolkit's implementation of List.

See Also:

List, java.awt.peer.ListPeer

protected abstract CheckboxPeer createCheckbox(Checkbox target)

Creates this toolkit's implementation of Checkbox using the specified peer interface.

Parameters:

target - the check box to be implemented.

Returns:

this toolkit's implementation of Checkbox.

See Also:

Checkbox, java.awt.peer.CheckboxPeer

protected abstract ScrollbarPeer createScrollbar(Scrollbar target)

Creates this toolkit's implementation of Scrollbar using the specified peer interface.

Parameters:

target - the scroll bar to be implemented.

Returns:

this toolkit's implementation of Scrollbar.

See Also:

Scrollbar, java.awt.peer.ScrollbarPeer

protected abstract ScrollPanePeer createScrollPane(ScrollPane target)

Creates this toolkit's implementation of ScrollPane using the specified peer interface.

Parameters:

target - the scroll pane to be implemented.

Returns:

this toolkit's implementation of ScrollPane.

See Also:

ScrollPane, java.awt.peer.ScrollPanePeer

protected abstract TextAreaPeer createTextArea(TextArea target)

Creates this toolkit's implementation of TextArea using the specified peer interface.

Parameters:

target - the text area to be implemented.

Returns:

this toolkit's implementation of TextArea.

See Also:

TextArea, java.awt.peer.TextAreaPeer

protected abstract ChoicePeer createChoice(Choice target)

Creates this toolkit's implementation of Choice using the specified peer interface.

Parameters:

target - the choice to be implemented.

Returns:

this toolkit's implementation of Choice.

See Also:

Choice, java.awt.peer.ChoicePeer

protected abstract FramePeer createFrame(Frame target)

Creates this toolkit's implementation of Frame using the specified peer interface.

Parameters:

target - the frame to be implemented.

Returns:

this toolkit's implementation of Frame.

See Also:

Frame, java.awt.peer.FramePeer

protected abstract CanvasPeer createCanvas(Canvas target)

Creates this toolkit's implementation of Canvas using the specified peer interface.

Parameters:

target - the canvas to be implemented.

Returns:

this toolkit's implementation of Canvas.

See Also:

Canvas, java.awt.peer.CanvasPeer

protected abstract PanelPeer createPanel(Panel target)

Creates this toolkit's implementation of Panel using the specified peer interface.

Parameters:

target - the panel to be implemented.

Returns:

this toolkit's implementation of Panel.

See Also:

Panel, java.awt.peer.PanelPeer

protected abstract WindowPeer createWindow(Window target)

Creates this toolkit's implementation of Window using the specified peer interface.

Parameters:

target - the window to be implemented.

Returns:

this toolkit's implementation of Window.

See Also:

Window, java.awt.peer.WindowPeer

protected abstract DialogPeer createDialog(Dialog target)

Creates this toolkit's implementation of Dialog using the specified peer interface.

Parameters:

target - the dialog to be implemented.

Returns:

this toolkit's implementation of Dialog.

See Also:

Dialog, java.awt.peer.DialogPeer

protected abstract MenuBarPeer createMenuBar(MenuBar target)

Creates this toolkit's implementation of MenuBar using the specified peer interface.

Parameters:

target - the menu bar to be implemented.

Returns:

this toolkit's implementation of MenuBar.

See Also:

MenuBar, java.awt.peer.MenuBarPeer

protected abstract MenuPeer createMenu(Menu target)

Creates this toolkit's implementation of Menu using the specified peer interface.

Parameters:

target - the menu to be implemented.

Returns:

this toolkit's implementation of Menu.

See Also:

Menu, java.awt.peer.MenuPeer

protected abstract PopupMenuPeer createPopupMenu(PopupMenu target)

Creates this toolkit's implementation of PopupMenu using the specified peer interface.

Parameters:

target - the popup menu to be implemented.

Returns:

this toolkit's implementation of PopupMenu.

See Also:

PopupMenu, java.awt.peer.PopupMenuPeer

protected abstract MenuItemPeer createMenuItem(MenuItem target)

Creates this toolkit's implementation of MenuItem using the specified peer interface.

Parameters:

target - the menu item to be implemented.

Returns:

this toolkit's implementation of MenuItem.

See Also:

MenuItem, java.awt.peer.MenuItemPeer

protected abstract FileDialogPeer createFileDialog(FileDialog target)

Creates this toolkit's implementation of FileDialog using the specified peer interface.

Parameters:

target - the file dialog to be implemented.

Returns:

this toolkit's implementation of FileDialog.

See Also:

FileDialog, java.awt.peer.FileDialogPeer

protected abstract CheckboxMenuItemPeer createCheckboxMenuItem(CheckboxMenuItem target)

Creates this toolkit's implementation of CheckboxMenuItem using the specified peer interface.

Parameters:

target - the checkbox menu item to be implemented.

Returns:

this toolkit's implementation of CheckboxMenuItem.

See Also:

CheckboxMenuItem, java.awt.peer.CheckboxMenuItemPeer

protected LightweightPeer createComponent(Component target)

Creates a peer for a component or container. This peer is windowless and allows the Component and Container classes to be extended directly to create windowless components that are defined entirely in java.

Parameters:

target - The Component to be created.

protected abstract FontPeer getFontPeer(String name,
                                        int style)

Creates this toolkit's implementation of Font using the specified peer interface.

Parameters:

target - the font to be implemented.

Returns:

this toolkit's implementation of Font.

See Also:

Font, java.awt.peer.FontPeer

protected void loadSystemColors(int[] systemColors)

Fills in the integer array that is supplied as an argument with the current system color values.

This method is called by the method updateSystemColors in the SystemColor class.

Parameters:

an - integer array.

See Also:

java.awt.SystemColor#updateSystemColors

public abstract Dimension getScreenSize()

Gets the size of the screen.

Returns:

the size of this toolkit's screen, in pixels.

public abstract int getScreenResolution()

Returns the screen resolution in dots-per-inch.

Returns:

this toolkit's screen resolution, in dots-per-inch.

public abstract ColorModel getColorModel()

Determines the color model of this toolkit's screen.

ColorModel is an abstract class that encapsulates the ability to translate between the pixel values of an image and its red, green, blue, and alpha components.

This toolkit method is called by the getColorModel method of the Component class.

Returns:

the color model of this toolkit's screen.

See Also:

ColorModel, getColorModel

public abstract String[] getFontList()

Returns the names of the available fonts in this toolkit.

For 1.1, the following font names are deprecated (the replacement name follows):

• TimesRoman (use Serif)
• Helvetica (use SansSerif)
• Courier (use Monospaced)

The ZapfDingbats font is also deprecated in 1.1, but only as a separate fontname. Unicode defines the ZapfDingbat characters starting at ?, and as of 1.1 Java supports those characters.

Returns:

the names of the available fonts in this toolkit.

public abstract FontMetrics getFontMetrics(Font font)

Gets the screen metrics of the font.

Parameters:

font - a font.

Returns:

the screen metrics of the specified font in this toolkit.

public abstract void sync()

Synchronizes this toolkit's graphics state. Some window systems may do buffering of graphics events.

This method ensures that the display is up-to-date. It is useful for animation.

public static Toolkit getDefaultToolkit()

Gets the default toolkit.

If there is a system property named "awt.toolkit", that property is treated as the name of a class that is a subclass of Toolkit.

If the system property does not exist, then the default toolkit used is the class named "sun.awt.motif.MToolkit", which is a motif implementation of the Abstract Window Toolkit.

Also loads additional classes into the VM using the property 'AWT.assistive_technologies' specified in the 'awt.properties' file. The form is "AWT.assistive_technologies=..." where the "..." is a comma-separated list of assistive technology classes to load. Each class is loaded in the order given and a single instance of each is created using Class.forName(class).newInstance(). This is done just after the AWT toolkit is created. All errors are handled via an AWTError exception.

Returns:

the default toolkit.

Throws: AWTError

if a toolkit could not be found, or if one could not be accessed or instantiated.

public abstract Image getImage(String filename)

Returns an image which gets pixel data from the specified file.

Parameters:

filename - the name of a file containing pixel data in a recognized file format.

Returns:

an image which gets its pixel data from the specified file.

public abstract Image getImage(URL url)

Returns an image which gets pixel data from the specified URL.

Parameters:

url - the URL to use in fetching the pixel data.

Returns:

an image which gets its pixel data from the specified URL.

public abstract boolean prepareImage(Image image,
                                     int width,
                                     int height,
                                     ImageObserver observer)

Prepares an image for rendering.

If the values of the width and height arguments are both -1, this method prepares the image for rendering on the default screen; otherwise, this method prepares an image for rendering on the default screen at the specified width and height.

The image data is downloaded asynchronously in another thread, and an appropriately scaled screen representation of the image is generated.

This method is called by components prepareImage methods.

Information on the flags returned by this method can be found with the definition of the ImageObserver interface.

Parameters:

image - the image for which to prepare a screen representation.

width - the width of the desired screen representation, or -1.

height - the height of the desired screen representation, or -1.

observer - the ImageObserver object to be notified as the image is being prepared.

Returns:

true if the image has already been fully prepared; false otherwise.

See Also:

java.awt.Component#prepareImage(java.awt.Image, java.awt.image.ImageObserver), java.awt.Component#prepareImage(java.awt.Image, int, int, java.awt.image.ImageObserver), ImageObserver

public abstract int checkImage(Image image,
                               int width,
                               int height,
                               ImageObserver observer)

Indicates the construction status of a specified image that is being prepared for display.

If the values of the width and height arguments are both -1, this method returns the construction status of a screen representation of the specified image in this toolkit. Otherwise, this method returns the construction status of a scaled representation of the image at the specified width and height.

This method does not cause the image to begin loading. An application must call prepareImage to force the loading of an image.

This method is called by the component's checkImage methods.

Information on the flags returned by this method can be found with the definition of the ImageObserver interface.

Parameters:

image - the image whose status is being checked.

width - the width of the scaled version whose status is being checked, or -1.

height - the height of the scaled version whose status is being checked, or -1.

observer - the ImageObserver object to be notified as the image is being prepared.

Returns:

the bitwise inclusive OR of the ImageObserver flags for the image data that is currently available.

See Also:

java.awt.Toolkit#prepareImage(java.awt.Image, int, int, java.awt.image.ImageObserver), java.awt.Component#checkImage(java.awt.Image, java.awt.image.ImageObserver), java.awt.Component#checkImage(java.awt.Image, int, int, java.awt.image.ImageObserver), ImageObserver

public abstract Image createImage(ImageProducer producer)

Creates an image with the specified image producer.

Parameters:

producer - the image producer to be used.

Returns:

an image with the specified image producer.

See Also:

Image, ImageProducer, createImage

public Image createImage(byte[] imagedata)

Creates an image which decodes the image stored in the specified byte array.

The data must be in some image format, such as GIF or JPEG, that is supported by this toolkit.

Parameters:

imagedata - an array of bytes, representing image data in a supported image format.

Returns:

an image.

public abstract Image createImage(byte[] imagedata,
                                  int imageoffset,
                                  int imagelength)

Creates an image which decodes the image stored in the specified byte array, and at the specified offset and length. The data must be in some image format, such as GIF or JPEG, that is supported by this toolkit.

Parameters:

imagedata - an array of bytes, representing image data in a supported image format.

imageoffset - the offset of the beginning of the data in the array.

imagelength - the length of the data in the array.

Returns:

an image.

public abstract PrintJob getPrintJob(Frame frame,
                                     String jobtitle,
                                     Properties props)

Gets a PrintJob object which is the result of initiating a print operation on the toolkit's platform.

Returns:

a PrintJob object, or null if the user cancelled the print job.

See Also:

PrintJob

public PageFormat setupPage(PageFormat page)

Display a dialog to the user allowing the modification of a PageFormat instance. The page argument is used to initialize controls in the page setup dialog. If the user cancels the dialog, then the method returns the original page object unmodified. If the user okays the dialog then the method returns a new PageFormat object with the indicated changes. In either case the original page object will not be modified. If the OS does not support a setup page dialog then the dialog will act as if the user cancelled the dialog.

Parameters:

page - the default PageFormat presented to the user for modification

Returns:

the original page object if the dialog is cancelled, or a new PageFormat object containing the format indicated by the user if the dialog is acknowledged

public boolean hasSetupPage()

Returns true if this Toolkit supports a Page Setup dialog for allowing a user to modify a PageFormat in the setupPage() method.

public abstract void beep()

Emits an audio beep.

public abstract Clipboard getSystemClipboard()

Gets an instance of the system clipboard which interfaces with clipboard facilities provided by the native platform.

This clipboard enables data transfer between Java programs and native applications which use native clipboard facilities.

Returns:

an instance of the system clipboard.

See Also:

Clipboard

public int getMenuShortcutKeyMask()

Determines which modifier key is the appropriate accelerator key for menu shortcuts.

Menu shortcuts, which are embodied in the MenuShortcut class, are handled by the MenuBar class.

By default, this method returns Event.CTRL_MASK. Toolkit implementations should override this method if the Control key isn't the correct key for accelerators.

Returns:

the modifier mask on the Event class that is used for menu shortcuts on this toolkit.

See Also:

MenuBar, MenuShortcut

protected static Container getNativeContainer(Component c)

Give native peers the ability to query the native container given a native component (eg the direct parent may be lightweight).

public Cursor createCustomCursor(Image cursor,
                                 Point hotSpot,
                                 String name) throws IndexOutOfBoundsException

Creates a new custom cursor object.

Parameters:

image - the image to display when the cursor is active.

hotSpot - the X and Y of the large cursor's hot spot. The hotSpot values must be less than the Dimension returned by getBestCursorSize().

name - a localized description of the cursor, for Java Accessibility use.

Throws: IndexOutOfBoundsException

if the hotSpot values are outside the bounds of the cursor.

public Dimension getBestCursorSize(int preferredWidth,
                                   int preferredHeight)

Returns the supported cursor dimension which is closest to the desired sizes. Systems which only support a single cursor size will return that size regardless of the desired sizes. Systems which don't support custom cursors will return a dimension of 0, 0.

Note: if an image is used whose dimensions don't match a supported size (as returned by this method), the Toolkit implementation will attempt to resize the image to a supported size. Since converting low-resolution images is difficult, no guarantees are made as to the quality of a cursor image which isn't a supported size. It is therefore recommended that this method be called and an appropriate image used so no image conversion is made.

Parameters:

desiredWidth - the preferred cursor width the component would like to use.

desiredHeight - the preferred cursor height the component would like to use.

Returns:

the closest matching supported cursor size, or a dimension of 0,0 if the Toolkit implementation doesn't support custom cursors.

public int getMaximumCursorColors()

Returns the maximum number of colors the Toolkit supports in a custom cursor palette.

Note: if an image is used which has more colors in its palette than the supported maximum, the Toolkit implementation will attempt to flatten the palette to the maximum. Since converting low-resolution images is difficult, no guarantees are made as to the quality of a cursor image which has more colors than the system supports. It is therefore recommended that this method be called and an appropriate image used so no image conversion is made.

Returns:

the maximum number of colors, or zero if custom cursors are not supported by this Toolkit implementation.

public static String getProperty(String key,
                                 String defaultValue)

Gets a property with the specified key and default. This method returns defaultValue if the property is not found.

public final EventQueue getSystemEventQueue()

Get the application's or applet's EventQueue instance. Depending on the Toolkit implementation, different EventQueues may be returned for different applets. Applets should therefore not assume that the EventQueue instance returned by this method will be shared by other applets or the system.

protected abstract EventQueue getSystemEventQueueImpl()

public abstract DragSourceContextPeer createDragSourceContextPeer(DragSource ds,
                                                                  Component c) throws InvalidDnDOperationException

create the peer for a DragSourceContext

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