виджет gwt - взаимоисключающий выключатель

gwt-ext toggleButtons

"This example illustrates Toggle Buttons. When clicked, such Buttons toggle their 'pressed' state.

The Bold, Italic and Underline toggle Buttons operate independently with respect to their toggle state while the text alignment icon Buttons belong to the same toggle group and so when one of them is click, the previously pressed Button returns to its normal state."

Вот мой вариант чистого гвта:

class ThreeStateMachine extends FlowPanel{
        // This is the main part - it will unset all the buttons in parent widget
        // and then set only clicked one.
        // One mutual handler works faster and is generally better for code reuse
        private final ClickHandler toggleToThis = new ClickHandler() {
                @Override
                public void onClick(ClickEvent clickEvent) {
                    for(Widget b: ThreeStateMachine.this.getChildren()){
                        ((ToggleButton)b).setDown(false);
                    }
                    ((ToggleButton)clickEvent.getSource()).setDown(true);
                }
            };

        private ThreeStateMachine() { // Create out widget and populat it with buttons
            super();

            ToggleButton b = new ToggleButton("one");
            b.setDown(true);
            b.addClickHandler(toggleToThis);
            this.add(b);

            b = new ToggleButton("two");
            b.addClickHandler(toggleToThis);
            this.add(b);

            b = new ToggleButton("three");
            b.addClickHandler(toggleToThis);
            this.add(b);
        }
    }

Конечно, для gwt-ToggleButton с вариантами (-up-hovering и т.д.) понадобится css-стиль