javax.swing.plaf.basic
class BasicTextUI

java.lang.Object javax.swing.plaf.ComponentUI javax.swing.plaf.TextUI javax.swing.plaf.basic.BasicTextUI

All Implemented Interfaces:

ViewFactory

Direct Known Subclasses:

BasicEditorPaneUI, BasicTextAreaUI, BasicTextFieldUI, DefaultTextUI

public abstract class BasicTextUI
extends TextUI
implements ViewFactory

Basis of a text components look-and-feel. This provides the basic editor view and controller services that may be useful when creating a look-and-feel for an extension of JTextComponent.

Most state is held in the associated JTextComponent as bound properties, and the UI installs default values for the various properties. This default will install something for all of the properties. Typically, a LAF implementation will do more however. At a minimum, a LAF would generally install key bindings.

This class also provides some concurrency support if the Document associated with the JTextComponent is a subclass of AbstractDocument. Access to the View (or View hierarchy) is serialized between any thread mutating the model and the Swing event thread (which is expected to render, do model/view coordinate translation, etc). Any access to the root view should first acquire a read-lock on the AbstractDocument and release that lock in a finally block.

An important method to define is the {@link #getPropertyPrefix} method which is used as the basis of the keys used to fetch defaults from the UIManager. The string should reflect the type of TextUI (eg. TextField, TextArea, etc) without the particular LAF part of the name (eg Metal, Motif, etc).

To build a view of the model, one of the following strategies can be employed.

1. One strategy is to simply redefine the ViewFactory interface in the UI. By default, this UI itself acts as the factory for View implementations. This is useful for simple factories. To do this reimplement the {@link #create} method.
2. A common strategy for creating more complex types of documents is to have the EditorKit implementation return a factory. Since the EditorKit ties all of the pieces necessary to maintain a type of document, the factory is typically an important part of that and should be produced by the EditorKit implementation.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the java.beans package. Please see {@link java.beans.XMLEncoder}.

BasicTextUI

public BasicTextUI()

Creates a new UI.

create

public View create(Element elem)

Creates a view for an element. If a subclass wishes to directly implement the factory producing the view(s), it should reimplement this method. By default it simply returns null indicating it is unable to represent the element.

Parameters:

elem - the element

Returns:

the view

create

public View create(Element elem,
                   int p0,
                   int p1)

Creates a view for an element. If a subclass wishes to directly implement the factory producing the view(s), it should reimplement this method. By default it simply returns null indicating it is unable to represent the part of the element.

Parameters:

elem - the element

p0 - the starting offset >= 0

p1 - the ending offset >= p0

Returns:

the view

createCaret

protected Caret createCaret()

Creates the object to use for a caret. By default an instance of BasicCaret is created. This method can be redefined to provide something else that implements the InputPosition interface or a subclass of JCaret.

Returns:

the caret object

createHighlighter

protected Highlighter createHighlighter()

Creates the object to use for adding highlights. By default an instance of BasicHighlighter is created. This method can be redefined to provide something else that implements the Highlighter interface or a subclass of DefaultHighlighter.

Returns:

the highlighter

createKeymap

protected Keymap createKeymap()

Creates the keymap to use for the text component, and installs any necessary bindings into it. By default, the keymap is shared between all instances of this type of TextUI. The keymap has the name defined by the getKeymapName method. If the keymap is not found, then DEFAULT_KEYMAP from JTextComponent is used.

The set of bindings used to create the keymap is fetched from the UIManager using a key formed by combining the {@link #getPropertyPrefix} method and the string .keyBindings. The type is expected to be JTextComponent.KeyBinding[].

Returns:

the keymap

damageRange

public void damageRange(JTextComponent tc,
                        int p0,
                        int p1)

Causes the portion of the view responsible for the given part of the model to be repainted. Does nothing if the view is not currently painted.

Overrides:

damageRange in class TextUI

Parameters:

tc - the text component for which this UI is installed

p0 - the beginning of the range >= 0

p1 - the end of the range >= p0

damageRange

public void damageRange(JTextComponent t,
                        int p0,
                        int p1,
                        Position.Bias p0Bias,
                        Position.Bias p1Bias)

Causes the portion of the view responsible for the given part of the model to be repainted.

Overrides:

damageRange in class TextUI

Parameters:

t

p0 - the beginning of the range >= 0

p1 - the end of the range >= p0

p0Bias

p1Bias

getComponent

protected final JTextComponent getComponent()

Fetches the text component associated with this UI implementation. This will be null until the ui has been installed.

Returns:

the editor component

getEditorKit

public EditorKit getEditorKit(JTextComponent tc)

Fetches the EditorKit for the UI.

Overrides:

getEditorKit in class TextUI

Parameters:

tc - the text component for which this UI is installed

Returns:

the editor capabilities

getKeymapName

protected String getKeymapName()

Fetches the name of the keymap that will be installed/used by default for this UI. This is implemented to create a name based upon the classname. The name is the the name of the class with the package prefix removed.

Returns:

the name

getMaximumSize

public Dimension getMaximumSize(JComponent c)

Gets the maximum size for the editor component.

Overrides:

getMaximumSize in class ComponentUI

Parameters:

c - the editor component

Returns:

the size

getMinimumSize

public Dimension getMinimumSize(JComponent c)

Gets the minimum size for the editor component.

Overrides:

getMinimumSize in class ComponentUI

Parameters:

c - the editor component

Returns:

the size

getNextVisualPositionFrom

public int getNextVisualPositionFrom(JTextComponent t,
                                     int pos,
                                     Position.Bias b,
                                     int direction,
                                     Position.Bias[] biasRet)
                              throws BadLocationException

{@inheritDoc}

Overrides:

getNextVisualPositionFrom in class TextUI

Parameters:

t

pos

b

direction

biasRet

Throws:

BadLocationException

getPreferredSize

public Dimension getPreferredSize(JComponent c)

Gets the preferred size for the editor component. If the component has been given a size prior to receiving this request, it will set the size of the view hierarchy to reflect the size of the component before requesting the preferred size of the view hierarchy. This allows formatted views to format to the current component size before answering the request. Other views don't care about currently formatted size and give the same answer either way.

Overrides:

getPreferredSize in class ComponentUI

Parameters:

c - the editor component

Returns:

the size

getPropertyPrefix

protected abstract String getPropertyPrefix()

Gets the name used as a key to look up properties through the UIManager. This is used as a prefix to all the standard text properties.

Returns:

the name

getRootView

public View getRootView(JTextComponent tc)

Fetches a View with the allocation of the associated text component (i.e. the root of the hierarchy) that can be traversed to determine how the model is being represented spatially.

NOTE:The View hierarchy can be traversed from the root view, and other things can be done as well. Things done in this way cannot be protected like simple method calls through the TextUI. Therefore, proper operation in the presence of concurrency must be arranged by any logic that calls this method!

Overrides:

getRootView in class TextUI

Parameters:

tc - the text component for which this UI is installed

Returns:

the view

getToolTipText

public String getToolTipText(JTextComponent t,
                             Point pt)

Returns the string to be used as the tooltip at the passed in location. This forwards the method onto the root View.

Overrides:

getToolTipText in class TextUI

Parameters:

t

pt

getVisibleEditorRect

protected Rectangle getVisibleEditorRect()

Gets the allocation to give the root View. Due to an unfortunate set of historical events this method is inappropriately named. The Rectangle returned has nothing to do with visibility. The component must have a non-zero positive size for this translation to be computed.

Returns:

the bounding box for the root view

installDefaults

protected void installDefaults()

Initializes component properties, e.g. font, foreground, background, caret color, selection color, selected text color, disabled text color, and border color. The font, foreground, and background properties are only set if their current value is either null or a UIResource, other properties are set if the current value is null.

installKeyboardActions

protected void installKeyboardActions()

installListeners

protected void installListeners()

Installs listeners for the UI.

installUI

public void installUI(JComponent c)

Installs the UI for a component. This does the following things.

1. Set the associated component to opaque (can be changed easily by a subclass or on JTextComponent directly), which is the most common case. This will cause the component's background color to be painted.
2. Install the default caret and highlighter into the associated component.
3. Attach to the editor and model. If there is no model, a default one is created.
4. create the view factory and the view hierarchy used to represent the model.

Overrides:

installUI in class ComponentUI

Parameters:

c - the editor component

modelChanged

protected void modelChanged()

Flags model changes. This is called whenever the model has changed. It is implemented to rebuild the view hierarchy to represent the default root element of the associated model.

modelToView

public Rectangle modelToView(JTextComponent tc,
                             int pos)
                      throws BadLocationException

Converts the given location in the model to a place in the view coordinate system. The component must have a non-zero positive size for this translation to be computed.

Overrides:

modelToView in class TextUI

Parameters:

tc - the text component for which this UI is installed

pos - the local location in the model to translate >= 0

Returns:

the coordinates as a rectangle, null if the model is not painted

Throws:

BadLocationException - if the given position does not represent a valid location in the associated document

modelToView

public Rectangle modelToView(JTextComponent tc,
                             int pos,
                             Position.Bias bias)
                      throws BadLocationException

Converts the given location in the model to a place in the view coordinate system. The component must have a non-zero positive size for this translation to be computed.

Overrides:

modelToView in class TextUI

Parameters:

tc - the text component for which this UI is installed

pos - the local location in the model to translate >= 0

bias

Returns:

the coordinates as a rectangle, null if the model is not painted

Throws:

BadLocationException - if the given position does not represent a valid location in the associated document

paint

public final void paint(Graphics g,
                        JComponent c)

Paints the interface. This is routed to the paintSafely method under the guarantee that the model won't change from the view of this thread while it's rendering (if the associated model is derived from AbstractDocument). This enables the model to potentially be updated asynchronously.

Overrides:

paint in class ComponentUI

Parameters:

g - the graphics context

c - the editor component

paintBackground

protected void paintBackground(Graphics g)

Paints a background for the view. This will only be called if isOpaque() on the associated component is true. The default is to paint the background color of the component.

Parameters:

g - the graphics context

paintSafely

protected void paintSafely(Graphics g)

Paints the interface safely with a guarantee that the model won't change from the view of this thread. This does the following things, rendering from back to front.

1. If the component is marked as opaque, the background is painted in the current background color of the component.
2. The highlights (if any) are painted.
3. The view hierarchy is painted.
4. The caret is painted.

Parameters:

g - the graphics context

propertyChange

protected void propertyChange(PropertyChangeEvent evt)

This method gets called when a bound property is changed on the associated JTextComponent. This is a hook which UI implementations may change to reflect how the UI displays bound properties of JTextComponent subclasses. This is implemented to do nothing (i.e. the response to properties in JTextComponent itself are handled prior to calling this method). This implementation updates the background of the text component if the editable and/or enabled state changes.

Parameters:

evt - the property change event

setView

protected final void setView(View v)

Sets the current root of the view hierarchy and calls invalidate(). If there were any child components, they will be removed (i.e. there are assumed to have come from components embedded in views).

Parameters:

v - the root view

uninstallDefaults

protected void uninstallDefaults()

Sets the component properties that haven't been explicitly overridden to null. A property is considered overridden if its current value is not a UIResource.

uninstallKeyboardActions

protected void uninstallKeyboardActions()

uninstallListeners

protected void uninstallListeners()

Uninstalls listeners for the UI.

uninstallUI

public void uninstallUI(JComponent c)

Deinstalls the UI for a component. This removes the listeners, uninstalls the highlighter, removes views, and nulls out the keymap.

Overrides:

uninstallUI in class ComponentUI

Parameters:

c - the editor component

update

public void update(Graphics g,
                   JComponent c)

Superclass paints background in an uncontrollable way (i.e. one might want an image tiled into the background). To prevent this from happening twice, this method is reimplemented to simply paint.

NOTE: Superclass is also not thread-safe in it's rendering of the background, although that's not an issue with the default rendering.

Overrides:

update in class ComponentUI

Parameters:

g

c

viewToModel

public int viewToModel(JTextComponent tc,
                       Point pt)

Converts the given place in the view coordinate system to the nearest representative location in the model. The component must have a non-zero positive size for this translation to be computed.

Overrides:

viewToModel in class TextUI

Parameters:

tc - the text component for which this UI is installed

pt - the location in the view to translate. This should be in the same coordinate system as the mouse events.

Returns:

the offset from the start of the document >= 0, -1 if not painted

viewToModel

public int viewToModel(JTextComponent tc,
                       Point pt,
                       Position.Bias[] biasReturn)

Converts the given place in the view coordinate system to the nearest representative location in the model. The component must have a non-zero positive size for this translation to be computed.

Overrides:

viewToModel in class TextUI

Parameters:

tc - the text component for which this UI is installed

pt - the location in the view to translate. This should be in the same coordinate system as the mouse events.

biasReturn

Returns:

the offset from the start of the document >= 0, -1 if the component doesn't yet have a positive size.