Adds an AttachEvent handler.

@param handler the handler @return the handler registration

HandlerRegistration addAttachHandler(AttachEventHandler handler) {
 return addHandler(handler, AttachEvent.TYPE);
}

For <a href= "http://code.google.com/p/google-web-toolkit/wiki/UnderstandingMemoryLeaks"

browsers which do not leak</a>, adds a native event handler to the widget.

Note that, unlike the {@link #addDomHandler(EventHandler, com.google.gwt.event.dom.client.DomEvent.Type)} implementation, there is no need to attach the widget to the DOM in order to cause the event handlers to be attached.

@param <H> the type of handler to add @param type the event key @param handler the handler @return {@link HandlerRegistration} used to remove the handler

HandlerRegistration addBitlessDomHandler(EventHandler handler, DomEventType type) {
 assert (handler != null);; // : "handler must not be null";
 assert (type != null); // : "type must not be null";
 sinkBitlessEvent(type.eventName);
 return ensureHandlers().addHandler(type, handler);
}

HandlerRegistration addBlurHandler(BlurHandler handler) {
 return addDomHandler(handler, BlurEvent.TYPE);
}

Adds a {@link ClickEvent} handler.

@param handler the click handler @return {@link HandlerRegistration} used to remove this handler

HandlerRegistration addClickHandler(ClickHandler handler) {
 return addDomHandler(handler, ClickEvent.TYPE);
}

Adds a native event handler to the widget and sinks the corresponding native event. If you do not want to sink the native event, use the generic addHandler method instead.

@param <H> the type of handler to add @param type the event key @param handler the handler @return {@link HandlerRegistration} used to remove the handler

HandlerRegistration addDomHandler(EventHandler handler, DomEventType type) {
 assert (handler != null); // : "handler must not be null";
 assert (type != null); // : "type must not be null";
 int typeInt = IEvent.getTypeInt(type.eventName);
 if (typeInt == -1) {
   sinkBitlessEvent(type.eventName);
 } else {
   sinkEvents(typeInt);
 }
 return ensureHandlers().addHandler(type, handler);
}

HandlerRegistration addDoubleClickHandler(DoubleClickHandler handler) {
 return addDomHandler(handler, DoubleClickEvent.TYPE);
}

HandlerRegistration addDragEndHandler(DragEndHandler handler) {
 return addBitlessDomHandler(handler, DragEndEvent.TYPE);
}

HandlerRegistration addDragEnterHandler(DragEnterHandler handler) {
 return addBitlessDomHandler(handler, DragEnterEvent.TYPE);
}

HandlerRegistration addDragHandler(DragHandler handler) {
 return addBitlessDomHandler(handler, DragEvent.TYPE);
}

HandlerRegistration addDragLeaveHandler(DragLeaveHandler handler) {
 return addBitlessDomHandler(handler, DragLeaveEvent.TYPE);
}

HandlerRegistration addDragOverHandler(DragOverHandler handler) {
 return addBitlessDomHandler(handler, DragOverEvent.TYPE);
}

HandlerRegistration addDragStartHandler(DragStartHandler handler) {
 return addBitlessDomHandler(handler, DragStartEvent.TYPE);
}

HandlerRegistration addDropHandler(DropHandler handler) {
 return addBitlessDomHandler(handler, DropEvent.TYPE);
}

HandlerRegistration addFocusHandler(FocusHandler handler) {
 return addDomHandler(handler, FocusEvent.TYPE);
}

HandlerRegistration addGestureChangeHandler(GestureChangeHandler handler) {
 return addDomHandler(handler, GestureChangeEvent.TYPE);
}

HandlerRegistration addGestureEndHandler(GestureEndHandler handler) {
 return addDomHandler(handler, GestureEndEvent.TYPE);
}

HandlerRegistration addGestureStartHandler(GestureStartHandler handler) {
 return addDomHandler(handler, GestureStartEvent.TYPE);
}

Adds this handler to the widget.

@param <H> the type of handler to add @param type the event type @param handler the handler @return {@link HandlerRegistration} used to remove the handler

HandlerRegistration addHandler(EventHandler handler, EventType<EventHandler> type) {
 return ensureHandlers().addHandler(type, handler);
}

HandlerRegistration addKeyDownHandler(KeyDownHandler handler) {
 return addDomHandler(handler, KeyDownEvent.TYPE);
}

HandlerRegistration addKeyPressHandler(KeyPressHandler handler) {
 return addDomHandler(handler, KeyPressEvent.TYPE);
}

HandlerRegistration addKeyUpHandler(KeyUpHandler handler) {
 return addDomHandler(handler, KeyUpEvent.TYPE);
}

HandlerRegistration addMouseDownHandler(MouseDownHandler handler) {
 return addDomHandler(handler, MouseDownEvent.TYPE);
}

HandlerRegistration addMouseMoveHandler(MouseMoveHandler handler) {
 return addDomHandler(handler, MouseMoveEvent.TYPE);
}

HandlerRegistration addMouseOutHandler(MouseOutHandler handler) {
 return addDomHandler(handler, MouseOutEvent.TYPE);
}

HandlerRegistration addMouseOverHandler(MouseOverHandler handler) {
 return addDomHandler(handler, MouseOverEvent.TYPE);
}

HandlerRegistration addMouseUpHandler(MouseUpHandler handler) {
 return addDomHandler(handler, MouseUpEvent.TYPE);
}

HandlerRegistration addMouseWheelHandler(MouseWheelHandler handler) {
 return addDomHandler(handler, MouseWheelEvent.TYPE);
}

Adds a dependent style name by specifying the style name's suffix. The actual form of the style name that is added is:

getStylePrimaryName() + '-' + styleSuffix

@param styleSuffix the suffix of the dependent style to be added. @see #setStylePrimaryName(String) @see #removeStyleDependentName(String) @see #setStyleDependentName(String, boolean) @see #addStyleName(String)

void addStyleDependentName(String styleSuffix) {
 setStyleDependentName(styleSuffix, true);
}

Adds a secondary or dependent style name to this object. A secondary style name is an additional style name that is, in HTML/CSS terms, included as a space-separated token in the value of the CSS <code>class</code> attribute for this object's root element.

The most important use for this method is to add a special kind of secondary style name called a dependent style name. To add a dependent style name, use {@link #addStyleDependentName(String)}, which will prefix the 'style' argument with the result of {@link #k()} (followed by a '-'). For example, suppose the primary style name is gwt-TextBox. If the following method is called as obj.setReadOnly(true):

public void setReadOnly(boolean readOnly) {
  isReadOnlyMode = readOnly;
  // Create a dependent style name.
  String readOnlyStyle = "readonly";
  if (readOnly) {
addStyleDependentName(readOnlyStyle);

  } else {
removeStyleDependentName(readOnlyStyle);

  }
}</pre>

then both of the CSS style rules below will be applied:
// This rule is based on the primary style name and is always active.
.gwt-TextBox {
  font-size: 12pt;
}
// This rule is based on a dependent style name that is only active
// when the widget has called addStyleName(getStylePrimaryName() +
// "-readonly").
.gwt-TextBox-readonly {
  background-color: lightgrey;
  border: none;
}</pre>

The code can also be simplified with
{@link #setStyleDependentName(String, boolean)}:
public void setReadOnly(boolean readOnly) {
  isReadOnlyMode = readOnly;
  setStyleDependentName("readonly", readOnly);
}

Dependent style names are powerful because they are automatically updated
whenever the primary style name changes. Continuing with the example above,
if the primary style name changed due to the following call:
setStylePrimaryName("my-TextThingy");

then the object would be re-associated with following style rules, removing
those that were shown above.
.my-TextThingy {
  font-size: 20pt;
}
.my-TextThingy-readonly {
  background-color: red;
  border: 2px solid yellow;
}</pre>

Secondary style names that are not dependent style names are not
automatically updated when the primary style name changes.

@param style the secondary style name to be added
@see UIObject
@see #removeStyleName(String)
void addStyleName(String style) {
 setStyleName(style, true);
}

HandlerRegistration addTouchCancelHandler(TouchCancelHandler handler) {
 return addDomHandler(handler, TouchCancelEvent.TYPE);
}

HandlerRegistration addTouchEndHandler(TouchEndHandler handler) {
 return addDomHandler(handler, TouchEndEvent.TYPE);
}

HandlerRegistration addTouchMoveHandler(TouchMoveHandler handler) {
 return addDomHandler(handler, TouchMoveEvent.TYPE);
}

HandlerRegistration addTouchStartHandler(TouchStartHandler handler) {
 return addDomHandler(handler, TouchStartEvent.TYPE);
}

Returns the Widget aspect of the receiver.

Widget asWidget() {
 return this;
}

Resets internal state if this button can no longer service events. This can occur when the widget becomes detached or disabled.

void cleanupCaptureState() {
 if (_isCapturing || _isFocusing) {
   Dom.releaseCapture(getElement());
   _isCapturing = false;
   _isFocusing = false;
   onClickCancel();
 }
}

Clears all of the object's style names and sets it to the given style. You should normally use {@link #setStylePrimaryName(String)} unless you wish to explicitly remove all existing styles.

@param style the new style name @see #setStylePrimaryName(String)

void clearAndSetStyleName(String style) {
 setElementStyleName(getStyleElement(), style);
}

Creates the SimpleEventBus used by this Widget. You can override this method to create a custom EventBus.

@return the EventBus you want to use.

EventBus createEventBus() {
 return new SimpleEventBus();
}

Fires an event on a child widget. Used to delegate the handling of an event from one widget to another.

@param event the event @param target fire the event on the given target

void delegateEvent(Widget target, DwtEvent event) {
 target.fireEvent(event);
}

If a widget contains one or more child widgets that are not in the logical widget hierarchy (the child is physically connected only on the DOM level), it must override this method and call {@link #onAttach()} for each of its child widgets.

@see #onAttach()

void doAttachChildren() {
}

If a widget contains one or more child widgets that are not in the logical widget hierarchy (the child is physically connected only on the DOM level), it must override this method and call {@link #onDetach()} for each of its child widgets.

@see #onDetach()

void doDetachChildren() {
}

Ensures the existence of the event bus.

@return the EventBus.

EventBus ensureHandlers() {
 return _eventBus == null ? _eventBus = createEventBus() : _eventBus;
}

Intended to be used to pull the value out of a CSS length. If the value is "auto" or "inherit", 0 will be returned.

@param s The CSS length string to extract @return The leading numeric portion of <code>s</code>, or 0 if "auto" or

    "inherit" are passed in.

double extractLengthValue(String s) {
 if (s == "auto" || s == "inherit" || s == "") {
   return 0.0;
 } else {
   // numberRegex divides the string into a leading numeric portion
   // followed by an arbitrary portion.
   if(numberRegex.hasMatch(s)) {
     // Extract the leading numeric portion of string
     s = numberRegex.firstMatch(s)[0];
   }
   return double.parse(s);
 }
}

Common setup between constructors.

void finishSetup() {
 if (_curFace == null) {
   setCurrentFace(getUpFace());
 }
}

void fireClickListeners(dart_html.Event nativeEvent) {
 // TODO(ecc) Once event triggering is committed, should fire a native click event instead.
 fireEvent(new ClickEvent());
}

Fires the given event to the handlers listening to the event's type.

Any exceptions thrown by handlers will be bundled into a UmbrellaException and then re-thrown after all handlers have completed. An exception thrown by a handler will not prevent other handlers from executing.

@param event the event

void fireEvent(DwtEvent event) {
//    if (_eventBus != null) {
//      _eventBus.fireEvent(event);
//    }
 if (_eventBus != null) {
   // If it not live we should revive it.
   if (!event.isLive()) {
     event.revive();
   }
   Object oldSource = event.getSource();
   event.overrideSource(getElement());
   try {

     // May throw an UmbrellaException.
     _eventBus.fireEventFromSource(event, getElement());
   } on UmbrellaException catch (e) {
     throw new UmbrellaException(e.causes);
   } finally {
     if (oldSource == null) {
       // This was my event, so I should kill it now that I'm done.
       event.kill();
     } else {
       // Restoring the source for the next handler to use.
       event.overrideSource(oldSource);
     }
   }
 }
}

Gets the object's absolute left position in pixels, as measured from the browser window's client area.

@return the object's absolute left position

int getAbsoluteLeft() {
 return Dom.getAbsoluteLeft(getElement());
}

Gets the object's absolute top position in pixels, as measured from the browser window's client area.

@return the object's absolute top position

int getAbsoluteTop() {
 return Dom.getAbsoluteTop(getElement());
}

Gets the current face of the button.

@return the current face

Face getCurrentFace() {
 /*
  * Implementation note: Package protected so we can use it when testing the
  * button.
  */
 finishSetup();
 return _curFace;
}

Gets the _downDisabled face of the button.

@return the _downDisabled face

Face getDownDisabledFace() {
 if (_downDisabled == null) {
   _setDownDisabledFace(_createFace(getDownFace(), "down-disabled", _DOWN_DISABLED));
 }
 return _downDisabled;
}

Gets the down face of the button.

@return the down face

Face getDownFace() {
 if (_down == null) {
   _setDownFace(_createFace(getUpFace(), "down", _DOWN));
 }
 return _down;
}

Gets the _downHovering face of the button.

@return the _downHovering face

Face getDownHoveringFace() {
 if (_downHovering == null) {
   _setDownHoveringFace(_createFace(getDownFace(), "down-hovering", _DOWN_HOVERING));
 }
 return _downHovering;
}

Gets this object's browser element.

dart_html.Element getElement() {
 assert (_element != null); // : MISSING_ELEMENT_ERROR;
 return _element;
}

Return EventBus.

EventBus getEventBus() {
 return _eventBus;
}

Gets the panel-defined layout data associated with this widget.

@return the widget's layout data @see #setLayoutData

Object getLayoutData() {
 return _layoutData;
}

dart_html.MouseEvent getMouseEvent(dart_html.Event evt) {
 return evt as dart_html.MouseEvent;
}

Gets the object's offset height in pixels. This is the total height of the object, including decorations such as border and padding, but not margin.

@return the object's offset height

int getOffsetHeight() {
 return getElement().offset.height; // Dom.getElementPropertyInt(getElement(), "offsetHeight");
}

Gets the object's offset width in pixels. This is the total width of the object, including decorations such as border and padding, but not margin.

@return the object's offset width

int getOffsetWidth() {
 return getElement().offset.width; // Dom.getElementPropertyInt(getElement(), "offsetWidth");
}

Gets this widget's parent panel.

@return the widget's parent panel

Widget getParent() {
 return _parent;
}

Template method that returns the element to which style names will be applied. By default it returns the root element, but this method may be overridden to apply styles to a child element.

@return the element to which style names will be applied

dart_html.Element getStyleElement() {
 return getElement();
}

Gets all of the object's style names, as a space-separated list. If you wish to retrieve only the primary style name, call {@link #getStylePrimaryName()}.

@return the objects's space-separated style names @see #getStylePrimaryName()

String getStyleName() {
 return getElementStyleName(getStyleElement());
}

Gets the primary style name associated with the object.

@return the object's primary style name @see #setStyleName(String) @see #addStyleName(String) @see #removeStyleName(String)

String getStylePrimaryName() {
 return getElementStylePrimaryName(getStyleElement());
}

Gets the _upDisabled face of the button.

@return the _upDisabled face

Face getUpDisabledFace() {
 if (_upDisabled == null) {
   _setUpDisabledFace(_createFace(getUpFace(), "up-disabled", _UP_DISABLED));
 }
 return _upDisabled;
}

Gets the up face of the button.

@return the up face

Face getUpFace() {
 return _up;
}

Gets the _upHovering face of the button.

@return the _upHovering face

Face getUpHoveringFace() {
 if (_upHovering == null) {
   _setUpHoveringFace(_createFace(getUpFace(), "up-hovering", _UP_HOVERING));
 }
 return _upHovering;
}

Returns whether or not the receiver is attached to the {@link com.google.gwt.dom.client.Document Document}'s {@link com.google.gwt.dom.client.BodyElement BodyElement}.

@return true if attached, false otherwise

bool isAttached() {
 return _attached;
}

Is this button down?

@return <code>true</code> if the button is down

bool isDown() {
 return (_DOWN_ATTRIBUTE & getCurrentFace().getFaceID()) > 0;
}

Is the mouse hovering over this button?

@return <code>true</code> if the mouse is hovering

bool isHovering() {
 return (_HOVERING_ATTRIBUTE & getCurrentFace().getFaceID()) > 0;
}

Has this widget ever been attached?

@return true if this widget ever been attached to the DOM, false otherwise

bool isOrWasAttached() {
 return eventsToSink == -1;
}

Overridden on attach to ensure that a button face has been chosen before the button is displayed.

void onAttach() {
 finishSetup();
 super.onAttach();
}

void onBrowserEvent(dart_html.Event event) {
 // Should not act on button if disabled.
 if (!enabled) {
   // This can happen when events are bubbled up from non-disabled children
   return;
 }

 int type = Dom.eventGetType(event);
 switch (type) {
   case IEvent.ONCLICK:
     // If clicks are currently disallowed, keep it from bubbling or being
     // passed to the superclass.
     if (!_allowClick) {
       event.stopPropagation();
       return;
     }
     break;
   case IEvent.ONMOUSEDOWN:
     if (getMouseEvent(event).button == IEvent.BUTTON_LEFT) {
       setFocus(true);
       onClickStart();
       Dom.setCapture(getElement());
       _isCapturing = true;
       // Prevent dragging (on some browsers);
       event.preventDefault();
     }
     break;
   case IEvent.ONMOUSEUP:
     if (_isCapturing) {
       _isCapturing = false;
       Dom.releaseCapture(getElement());
       if (isHovering() && getMouseEvent(event).button == IEvent.BUTTON_LEFT) {
         onClick();
       }
     }
     break;
   case IEvent.ONMOUSEMOVE:
     if (_isCapturing) {
       // Prevent dragging (on other browsers);
       event.preventDefault();
     }
     break;
   case IEvent.ONMOUSEOUT:
     dart_html.Element to = Dom.eventGetToElement(event);
     if (Dom.isOrHasChild(getElement(), event.target)
         && (to == null || !Dom.isOrHasChild(getElement(), to))) {
       if (_isCapturing) {
         onClickCancel();
       }
       setHovering(false);
     }
     break;
   case IEvent.ONMOUSEOVER:
     if (Dom.isOrHasChild(getElement(), event.target)) {
       setHovering(true);
       if (_isCapturing) {
         onClickStart();
       }
     }
     break;
   case IEvent.ONBLUR:
     if (_isFocusing) {
       _isFocusing = false;
       onClickCancel();
     }
     break;
   case IEvent.ONLOSECAPTURE:
     if (_isCapturing) {
       _isCapturing = false;
       onClickCancel();
     }
     break;
 }

 super.onBrowserEvent(event);

 // Synthent is size clicks based on keyboard events AFTER the normal key handling.
 if ((event is dart_html.KeyboardEvent) && (IEvent.getTypeInt(event.type) & IEvent.KEYEVENTS) != 0) {
   int keyCode = (event as dart_html.KeyboardEvent).keyCode;
   switch (type) {
     case IEvent.ONKEYDOWN:
       if (keyCode == ' '.codeUnitAt(0)) {
         _isFocusing = true;
         onClickStart();
       }
       break;
     case IEvent.ONKEYUP:
       if (_isFocusing && keyCode == ' '.codeUnitAt(0)) {
         _isFocusing = false;
         onClick();
       }
       break;
     case IEvent.ONKEYPRESS:
       if (keyCode == '\n'.codeUnitAt(0) || keyCode == '\r'.codeUnitAt(0)) {
         onClickStart();
         onClick();
       }
       break;
   }
 }
}

Called when the user aborts a click in progress; for example, by dragging the mouse outside of the button before releasing the mouse button. Subclasses that override {@link #onClickStart()} should override this method to restore the normal widget display.

void onClickCancel() { }

Called when the user begins to click on this button. Subclasses may override this method to display the start of the click visually; such subclasses should also override {@link #onClick()} and {@link #onClickCancel()} to restore normal visual state. Each <code>onClickStart</code> will eventually be followed by either <code>onClick</code> or <code>onClickCancel</code>, depending on whether the click is completed.

void onClickStart() { }

void onDetach() {
 super.onDetach();
 cleanupCaptureState();
 setHovering(false);
}

This method is called immediately after a widget becomes attached to the browser's document.

void onLoad() {
}

This method is called immediately before a widget will be detached from the browser's document.

void onUnload() {
}

Removes this widget from its parent widget, if one exists.

If it has no parent, this method does nothing. If it is a "root" widget (meaning it's been added to the detach list via {@link RootPanel#detachOnWindowClose(Widget)}), it will be removed from the detached immediately. This makes it possible for Composites and Panels to adopt root widgets.

@throws IllegalStateException if this widget's parent does not support

      removal (e.g. {@link Composite})

void removeFromParent() {
 if (_parent == null) {
   // If the widget had no parent, check to see if it was in the detach list
   // and remove it if necessary.
   if (RootPanel.isInDetachList(this)) {
     RootPanel.detachNow(this);
   }
 } else if (_parent is HasWidgets) {
   (_parent as HasWidgets).remove(this);
 } else if (_parent != null) {
   throw new Exception("This widget's parent does not implement HasWidgets");
 }
}

Removes a dependent style name by specifying the style name's suffix.

@param styleSuffix the suffix of the dependent style to be removed @see #setStylePrimaryName(Element, String) @see #addStyleDependentName(String) @see #setStyleDependentName(String, boolean)

void removeStyleDependentName(String styleSuffix) {
 setStyleDependentName(styleSuffix, false);
}

Removes a style name. This method is typically used to remove secondary style names, but it can be used to remove primary stylenames as well. That use is not recommended.

@param style the secondary style name to be removed @see #addStyleName(String) @see #setStyleName(String, boolean)

void removeStyleName(String style) {
 setStyleName(style, false);
}

Replaces this object's browser element.

This method exists only to support a specific use-case in Image, and should not be used by other classes.

@param elem the object's new element

void replaceElement(dart_html.Element elem) {
 if (isAttached()) {
   // Remove old event listener to avoid leaking. onDetach will not do this
   // for us, because it is only called when the widget itself is detached
   // from the document.
   Dom.setEventListener(getElement(), null);
 }

 super.replaceElement(elem);

 if (isAttached()) {
   // Hook the event listener back up on the new element. onAttach will not
   // do this for us, because it is only called when the widget itself is
   // attached to the document.
   Dom.setEventListener(getElement(), this);
 }
}

void setAccessKey(int key) {
 FocusPanel.impl.setAccessKey(getElement(), key);
}

void setCurrentFace(Face newFace) {
 /*
  * Implementation note: default access for testing.
  */
 if (_curFace != newFace) {
   if (_curFace != null) {
     removeStyleDependentName(_curFace.getName());
   }
   _curFace = newFace;
   _setCurrentFaceElement(newFace.getFace());
   addStyleDependentName(_curFace.getName());

   if (enabled) {
     _setAriaPressed(newFace);
   }
 }
}

Sets whether this button is down.

@param down <code>true</code> to press the button, <code>false</code> otherwise

void setDown(bool down) {
 if (down != isDown()) {
   toggleDown();
 }
}

Sets this object's browser element. UIObject subclasses must call this method before attempting to call any other methods, and it may only be called once.

@param elem the object's element

void setElement(dart_html.Element elem) {
 assert (_element == null);
 this._element = elem;
}

void setFocus(bool focused) {
 if (focused) {
   FocusPanel.impl.focus(getElement());
 } else {
   FocusPanel.impl.blur(getElement());
 }
}

Sets the object's height. This height does not include decorations such as border, margin, and padding.

@param height the object's new height, in CSS units (e.g. "10px", "1em")

void setHeight(String height) {
 // This exists to deal with an inconsistency in IE's implementation where
 // it won't accept negative numbers in length measurements
 assert (extractLengthValue(height.trim().toLowerCase()) >= 0); // : "CSS heights should not be negative";
 Dom.setStyleAttribute(getElement(), "height", height);
}

Sets whether this button is hovering.

@param hovering is this button hovering?

void setHovering(bool hovering) {
 if (hovering != isHovering()) {
   toggleHover();
 }
}

Sets the panel-defined layout data associated with this widget. Only the panel that currently contains a widget should ever set this value. It serves as a place to store layout bookkeeping data associated with a widget.

@param layoutData the widget's layout data

void setLayoutData(Object value) {
 this._layoutData = value;
}

Sets this widget's parent. This method should only be called by {@link Panel} and {@link Composite}.

@param parent the widget's new parent @throws IllegalStateException if <code>parent</code> is non-null and the

      widget already has a parent

void setParent(Widget parent) {
 Widget oldParent = this._parent;
 if (parent == null) {
   try {
     if (oldParent != null && oldParent.isAttached()) {
       onDetach();
       assert (!isAttached()); // : "Failure of " + this.getClass().getName() + " to call super.onDetach()";
     }
   } finally {
     // Put this in a finally in case onDetach throws an exception.
     this._parent = null;
   }
 } else {
   if (oldParent != null) {
     throw new Exception("Cannot set a new parent without first clearing the old parent");
   }
   this._parent = parent;
   if (parent.isAttached()) {
     onAttach();
     assert (isAttached()); // : "Failure of " + this.getClass().getName() + " to call super.onAttach()";
   }
 }
}

Sets the object's size, in pixels, not including decorations such as border, margin, and padding.

@param width the object's new width, in pixels @param height the object's new height, in pixels

void setPixelSize(int width, int height) {
 if (width >= 0) {
   setWidth(width.toString() + "px");
 }
 if (height >= 0) {
   setHeight(height.toString() + "px");
 }
}

Sets the object's size. This size does not include decorations such as border, margin, and padding.

@param width the object's new width, in CSS units (e.g. "10px", "1em") @param height the object's new height, in CSS units (e.g. "10px", "1em")

void setSize(String width, String height) {
 setWidth(width);
 setHeight(height);
}

Adds or removes a dependent style name by specifying the style name's suffix. The actual form of the style name that is added is:

getStylePrimaryName() + '-' + styleSuffix

@param styleSuffix the suffix of the dependent style to be added or removed @param add <code>true</code> to add the given style, <code>false</code> to

     remove it

@see #setStylePrimaryName(Element, String) @see #addStyleDependentName(String) @see #setStyleName(String, boolean) @see #removeStyleDependentName(String)

void setStyleDependentName(String styleSuffix, bool add) {
 setStyleName(getStylePrimaryName() + '-' + styleSuffix, add);
}

Adds or removes a style name. This method is typically used to remove secondary style names, but it can be used to remove primary stylenames as well. That use is not recommended.

@param style the style name to be added or removed @param add <code>true</code> to add the given style, <code>false</code> to

     remove it

@see #addStyleName(String) @see #removeStyleName(String)

void setStyleName(String style, bool add) {
 manageElementStyleName(getStyleElement(), style, add);
}

Sets the object's primary style name and updates all dependent style names.

@param style the new primary style name @see #addStyleName(String) @see #removeStyleName(String)

void setStylePrimaryName(String style) {
 setElementStylePrimaryName(getStyleElement(), style);
}

Sets the up face of the button.

@param up up face

void setUpFace(Face up) {
 this._up = up;
}

Sets the object's width. This width does not include decorations such as border, margin, and padding.

@param width the object's new width, in CSS units (e.g. "10px", "1em")

void setWidth(String width) {
 // This exists to deal with an inconsistency in IE's implementation where
 // it won't accept negative numbers in length measurements
 assert (extractLengthValue(width.trim().toLowerCase()) >= 0); // : "CSS widths should not be negative";
 Dom.setStyleAttribute(getElement(), "width", width);
}

Sinks a named event. Note that only {@link Widget widgets} may actually receive events, but can receive events from all objects contained within them.

@param eventTypeName name of the event to sink on this element @see com.google.gwt.user.client.Event

void sinkBitlessEvent(String eventTypeName) {
 Dom.sinkBitlessEvent(getElement(), eventTypeName);
}

Overridden to defer the call to super.sinkEvents until the first time this widget is attached to the dom, as a performance enhancement. Subclasses wishing to customize sinkEvents can preserve this deferred sink behavior by putting their implementation behind a check of <code>isOrWasAttached()</code>:

{@literal @}Override
public void sinkEvents(int eventBitsToAdd) {
  if (isOrWasAttached()) {
    /{@literal *} customized sink code goes here {@literal *}/
  } else {
    super.sinkEvents(eventBitsToAdd);
 }
} 

void sinkEvents(int eventBitsToAdd) {
 if (isOrWasAttached()) {
   super.sinkEvents(eventsToSink);
 } else {
   eventsToSink |= eventBitsToAdd;
 }
}

Toggle the disabled attribute.

void toggleDisabled() {
 // Toggle disabled.
 int newFaceID = getCurrentFace().getFaceID() ^ _DISABLED_ATTRIBUTE;

 // Remove hovering.
 newFaceID &= ~_HOVERING_ATTRIBUTE;

 // Sets the current face.
 _setCurrentFace(newFaceID);
}

Toggle the up/down attribute.

void toggleDown() {
 int newFaceID = getCurrentFace().getFaceID() ^ _DOWN_ATTRIBUTE;
 _setCurrentFace(newFaceID);
}

Toggle the hovering attribute.

void toggleHover() {
 // Toggle hovering.
 int newFaceID = getCurrentFace().getFaceID() ^ _HOVERING_ATTRIBUTE;

 // Remove disabled.
 newFaceID &= ~_DISABLED_ATTRIBUTE;
 _setCurrentFace(newFaceID);
}

This method is overridden so that any object can be viewed in the debugger as an HTML snippet.

@return a string representation of the object

String toString() {
 if (_element == null) {
   return "(null handle)";
 }
 return getElement().toString();
}

Removes a set of events from this object's event list.

@param eventBitsToRemove a bitfield representing the set of events to be

     removed from this element's event set

@see #sinkEvents @see com.google.gwt.user.client.Event

void unsinkEvents(int eventBitsToRemove) {
 Dom.sinkEvents(getElement(), Dom.getEventsSunk(getElement()) & (~eventBitsToRemove));
}