asquare.gwt.tk.client.ui.behavior
Class FocusModel

java.lang.Object
  asquare.gwt.tk.client.ui.behavior.FocusModel

public class FocusModel
extends Object

A primitive focus model. Tracks the widgets in a focus cycle and which widget should be focused.

Constructor Summary

FocusModel()

Method Summary

void	add(HasFocus widget) Add a widget to the model.
void	add(HasFocus[] widgets) Add widgets to the model in bulk.
void	addListener(FocusModelListener listener)
void	clear() Remove all widgets from the model.
int	getCurrentIndex() Get the index corresponding to the currently focused widget.
HasFocus	getFocusWidget() Get the widget which is focused.
int	getIndexOf(HasFocus widget) Get the index of the specified widget in the model.
HasFocus	getNextWidget() Get the widget after the currently focused widget.
HasFocus	getNextWidget(boolean forward) Get the next widget in the cycle.
HasFocus	getPreviousWidget() Get the widget previous to the currently focused widget.
int	getSize() Get the number of widgets in the model.
HasFocus	getWidgetAt(int index) Get the widget at the specified index.
void	insert(HasFocus widget, int index) Inserts a widget into to the model at the specified index.
void	remove(HasFocus widget) Removes a widget from the model.
void	removeListener(FocusModelListener listener)
void	setFocusWidget(HasFocus widget) Set the widget which is focused.
protected boolean	shouldAdd(HasFocus widget) Determines whether the specified Widget can be added to the model.
protected boolean	shouldFocus(HasFocus w) Determines whether the specified Widget can receive focus.

Methods inherited from class java.lang.Object

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

Constructor Detail

FocusModel

public FocusModel()

Method Detail

addListener

public void addListener(FocusModelListener listener)

removeListener

public void removeListener(FocusModelListener listener)

getSize

public int getSize()

Get the number of widgets in the model.

clear

public void clear()

Remove all widgets from the model.

add

public void add(HasFocus[] widgets)

Add widgets to the model in bulk.

Parameters:

widgets - an array of 0 or more widgets

Throws:

IllegalArgumentException - if widgets is null

IllegalArgumentException - if an element is null

IllegalArgumentException - if an element is already present in the model

See Also:

shouldAdd(HasFocus)

add

public void add(HasFocus widget)

Add a widget to the model.

Parameters:

widget - a widget

Throws:

IllegalArgumentException - if widget is null

IllegalArgumentException - if widget is already present in the model

See Also:

shouldAdd(HasFocus)

insert

public void insert(HasFocus widget,
                   int index)

Inserts a widget into to the model at the specified index.

Parameters:

widget - a widget

index - an integer greater than 0 and less than or equal to number of widgets in the model

Throws:

IllegalArgumentException - if widget is null

IllegalArgumentException - if widget is already present in the model

IndexOutOfBoundsException - if index < 0 || index > getSize()

See Also:

shouldAdd(HasFocus)

shouldAdd

protected boolean shouldAdd(HasFocus widget)

Determines whether the specified Widget can be added to the model.

Parameters:

widget - a widget which is candidate to be added to the model

Returns:

true if widget.getTabIndex() >= 0

getCurrentIndex

public int getCurrentIndex()

Get the index corresponding to the currently focused widget.

Returns:

a value between 0 and getSize(), or -1 if no widget is focused

getIndexOf

public int getIndexOf(HasFocus widget)

Get the index of the specified widget in the model.

Parameters:

widget - a widget

Returns:

a valid index, or -1 if widget is not present in the model

Throws:

IllegalArgumentException - if widget is null

getWidgetAt

public HasFocus getWidgetAt(int index)

Get the widget at the specified index.

Parameters:

index - an integer greater than 0 and less than or equal to number of widgets in the model

Returns:

the widget

Throws:

IndexOutOfBoundsException - if index is out of range

remove

public void remove(HasFocus widget)

Removes a widget from the model.

Parameters:

widget -

getFocusWidget

public HasFocus getFocusWidget()

Get the widget which is focused.

Returns:

a widget, or null if no widget is focused

setFocusWidget

public void setFocusWidget(HasFocus widget)

Set the widget which is focused.

Parameters:

widget - a widget in the model, or null

Throws:

IllegalArgumentException - if widget is not present in the model and not null

getNextWidget

public HasFocus getNextWidget(boolean forward)

Get the next widget in the cycle. The widget is skipped if (widget.getTabIndex() < 0 || ! widget.isEnabled()).

Parameters:

forward - true to cycle forward, false to cycle backward

Returns:

the next focusable widget, or
the currently focused widget if no other focusable widget is available, or
null no if focusable widget is available

Throws:

IllegalStateException - if the model is empty

getNextWidget

public HasFocus getNextWidget()

Get the widget after the currently focused widget.

Returns:

the next widget

Throws:

IllegalStateException - if the model is empty

getPreviousWidget

public HasFocus getPreviousWidget()

Get the widget previous to the currently focused widget.

Returns:

the previous widget

Throws:

IllegalStateException - if the model is empty

shouldFocus

protected boolean shouldFocus(HasFocus w)

Determines whether the specified Widget can receive focus.

Parameters:

w - a widget in this model which is candidate for focus

Returns:

true unless w is a disabled FocusWidget