SashWidthHandler.java

package net.jeeeyul.eclipse.themes.css;

import net.jeeeyul.eclipse.themes.rendering.internal.HackedField;

import org.eclipse.e4.ui.css.core.dom.properties.ICSSPropertyHandler;
import org.eclipse.e4.ui.css.core.engine.CSSEngine;
import org.eclipse.e4.ui.css.swt.dom.CompositeElement;
import org.eclipse.e4.ui.workbench.renderers.swt.SashLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Layout;
import org.w3c.dom.css.CSSPrimitiveValue;
import org.w3c.dom.css.CSSValue;

/**
 * CSS Property handler for "jsash-width" property of Composite elements.
 * 
 * @author Jeeeyul
 */
@SuppressWarnings("restriction")
public class SashWidthHandler implements ICSSPropertyHandler {
	private HackedField<SashLayout, Integer> sashWidth = new HackedField<SashLayout, Integer>(SashLayout.class, "sashWidth");

	@Override
	public boolean applyCSSProperty(Object element, String property, CSSValue value, String pseudo, CSSEngine engine) throws Exception {
		if (!(element instanceof CompositeElement)) {
			return false;
		}
		CompositeElement compositeElement = (CompositeElement) element;
		Object nativeWidget = compositeElement.getNativeWidget();
		if (!(nativeWidget instanceof Composite)) {
			return false;
		}

		Composite composite = (Composite) nativeWidget;
		Layout layout = composite.getLayout();
		if (!(layout instanceof SashLayout)) {
			return false;
		}

		if (!(value instanceof CSSPrimitiveValue)) {
			return false;
		}

		int newWidth = (int) ((CSSPrimitiveValue) value).getFloatValue(CSSPrimitiveValue.CSS_PX);
		sashWidth.set(layout, newWidth);

		composite.layout(true, true);
		return true;
	}

	@Override
	public String retrieveCSSProperty(Object element, String property, String pseudo, CSSEngine engine) throws Exception {
		if (!(element instanceof CompositeElement)) {
			return null;
		}
		CompositeElement compositeElement = (CompositeElement) element;
		Object nativeWidget = compositeElement.getNativeWidget();
		if (!(nativeWidget instanceof Composite)) {
			return null;
		}

		Composite composite = (Composite) nativeWidget;
		Layout layout = composite.getLayout();
		if (!(layout instanceof SashLayout)) {
			return null;
		}

		Integer width = sashWidth.get(layout);
		return Integer.toString(width);
	}

}