UiLayoutPanelTagFactory.java

package com.googlecode.gwt.test.uibinder.widget;

import com.google.gwt.dom.client.Element;
import com.google.gwt.user.client.ui.IsWidget;
import com.google.gwt.user.client.ui.LayoutPanel;
import com.googlecode.gwt.test.uibinder.UiBinderXmlUtils;
import com.googlecode.gwt.test.uibinder.UiObjectTag;
import com.googlecode.gwt.test.uibinder.UiObjectTagFactory;

import java.util.List;
import java.util.Map;

/**
 * Handles <g:LayoutPanel> tags.
 *
 * @author Gael Lazzari
 */
public class UiLayoutPanelTagFactory implements UiObjectTagFactory<LayoutPanel> {

    private static class UiLayoutPanelTag extends UiObjectTag<LayoutPanel> {

        @Override
        protected void appendElement(LayoutPanel wrapped, Element element, String namespaceURI,
                                     List<IsWidget> childWidgets) {

            if (!UiBinderXmlUtils.CLIENTUI_NSURI.equals(namespaceURI)) {
                super.appendElement(wrapped, element, namespaceURI, childWidgets);
            } else {

                if (childWidgets.size() > 0) {
                    handleLayoutPanelSpecifics(wrapped, element, childWidgets);
                }
            }
        }

        @Override
        protected void finalizeObject(LayoutPanel widget) {
            // nothing to do
        }

        @Override
        protected void initializeObject(LayoutPanel wrapped, Map<String, Object> attributes,
                                        Object owner) {
            // nothing to do
        }

        private void handleLayoutPanelSpecifics(LayoutPanel wrapped, Element element,
                                                List<IsWidget> childWidgets) {

            // The valid sets of horizontal constraints are:
            // (none) : Fill the parent's horizontal axis
            // left, width : Fixed width, positioned from parent's left edge
            // right, width : Fixed width, positioned from parent's right edge
            // left, right : Width implied by fixed distance from parent's left and
            // right edges

            // The valid sets of vertical constraints are:
            // (none) : Fill the parent's vertical axis
            // top, height : Fixed height, positioned from parent's top edge
            // bottom, height : Fixed height, positioned from parent's bottom edge
            // top, bottom : Height implied by fixed distance from parent's top and
            // bottom edges

            // The values of constraint attributes can be any valid CSS length,
            // such
            // as 1px, 3em, or 0 (zero lengths require no units).

            // String left = element.getAttribute("left");
            // String right = element.getAttribute("right");
            // String width = element.getAttribute("width");
            //
            // String top = element.getAttribute("top");
            // String bottom = element.getAttribute("bottom");
            // String height = element.getAttribute("height");

            for (IsWidget child : childWidgets) {
                wrapped.add(child);
                // TODO : handle layer size and position data
            }

        }

    }

    public UiObjectTag<LayoutPanel> createUiObjectTag(Class<?> clazz, Map<String, Object> attributes) {

        if (LayoutPanel.class.isAssignableFrom(clazz)) {
            return new UiLayoutPanelTag();
        }

        return null;
    }

}