CustomCSSHelpHoverProvider.java

/**
 * Copyright (c) 2012 committers of YAKINDU and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * Contributors:
 * 	committers of YAKINDU - initial API and implementation
 * 
 */
package org.yakindu.sct.model.stext.ui.help;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;

import org.eclipse.jface.action.Action;
import org.eclipse.jface.action.ToolBarManager;
import org.eclipse.jface.internal.text.html.BrowserInformationControl;
import org.eclipse.jface.internal.text.html.HTMLPrinter;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.text.AbstractReusableInformationControlCreator;
import org.eclipse.jface.text.DefaultInformationControl;
import org.eclipse.jface.text.IInformationControl;
import org.eclipse.jface.text.IInformationControlCreator;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.ISharedImages;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.editors.text.EditorsUI;
import org.eclipse.ui.help.IWorkbenchHelpSystem;
import org.eclipse.xtext.ui.editor.hover.html.IXtextBrowserInformationControl;
import org.yakindu.base.utils.jface.help.HelpHoverProvider;
import org.yakindu.sct.model.stext.ui.internal.STextActivator;

import com.google.inject.Inject;
import com.google.inject.name.Named;

/**
 * Overrides the loadStylesheet method to load a custom stylesheet from this
 * plugin. The HoverControlCreator is overridden too, because we don't want to
 * have the status line visible. (Not possible to set the bg color of the status
 * line)
 * 
 * 
 * @author andreas muelder - Initial contribution and API
 * 
 */
@SuppressWarnings("restriction")
public class CustomCSSHelpHoverProvider extends HelpHoverProvider {

	private String fgStyleSheet = null;

	@Inject(optional = true)
	@Named("org.eclipse.xtext.ui.editor.hover.XtextEditorHover.font")
	private String fontSymbolicName = "org.eclipse.jdt.ui.javadocfont"; //$NON-NLS-1$ 

	@Inject
	@Named("stylesheet")
	private String styleSheetFileName;

	private HoverControlCreator hoverControlCreator;
	private PresenterControlCreator presenterControlCreator;

	protected String getStyleSheet() {
		if (fgStyleSheet == null)
			fgStyleSheet = loadStyleSheet();
		String css = fgStyleSheet;
		if (css != null) {
			FontData fontData = JFaceResources.getFontRegistry().getFontData(
					fontSymbolicName)[0];
			css = HTMLPrinter.convertTopLevelFont(css, fontData);
		}
		return css;
	}

	protected String loadStyleSheet() {
		URL styleSheetURL = STextActivator.getInstance().getBundle()
				.getEntry(styleSheetFileName); //$NON-NLS-1$
		if (styleSheetURL != null) {
			BufferedReader reader = null;
			try {
				reader = new BufferedReader(new InputStreamReader(
						styleSheetURL.openStream()));
				StringBuffer buffer = new StringBuffer(1500);
				String line = reader.readLine();
				while (line != null) {
					buffer.append(line);
					buffer.append('\n');
					line = reader.readLine();
				}
				return buffer.toString();
			} catch (IOException ex) {
				return ""; //$NON-NLS-1$
			} finally {
				try {
					if (reader != null)
						reader.close();
				} catch (IOException e) {
				}
			}
		}
		return null;
	}

	public IInformationControlCreator getInformationPresenterControlCreator() {
		if (presenterControlCreator == null)
			presenterControlCreator = new CustomPresenterControlCreator();
		return presenterControlCreator;
	}

	public IInformationControlCreator getHoverControlCreator() {
		if (hoverControlCreator == null)
			hoverControlCreator = new HoverControlCreator(
					getInformationPresenterControlCreator());
		return hoverControlCreator;
	}

	public final class HoverControlCreator extends
			AbstractReusableInformationControlCreator {

		private final IInformationControlCreator fInformationPresenterControlCreator;

		public HoverControlCreator(
				IInformationControlCreator informationPresenterControlCreator) {
			fInformationPresenterControlCreator = informationPresenterControlCreator;
		}

		@Override
		public IInformationControl doCreateInformationControl(Shell parent) {
			String tooltipAffordanceString = EditorsUI
					.getTooltipAffordanceString();
			if (BrowserInformationControl.isAvailable(parent)) {
				String font = "org.eclipse.jdt.ui.javadocfont";
				BrowserInformationControl iControl = new BrowserInformationControl(
						parent, font, false) {
					@Override
					public IInformationControlCreator getInformationPresenterControlCreator() {
						return fInformationPresenterControlCreator;
					}
				};
				addLinkListener(iControl);
				return iControl;
			} else {
				return new DefaultInformationControl(parent,
						tooltipAffordanceString);
			}
		}
	}

	public class CustomPresenterControlCreator extends PresenterControlCreator {

		protected void configureControl(
				IXtextBrowserInformationControl control, ToolBarManager tbm,
				String font) {
			OpenInHelpAction openHelpAction = new OpenInHelpAction();
			openHelpAction.setEnabled(true);
			tbm.add(openHelpAction);
			tbm.update(true);
		};

	}

	private static final class OpenInHelpAction extends Action {

		public OpenInHelpAction() {
			setText("Open user guide");
			setImageDescriptor(ImageDescriptor.createFromImage(PlatformUI
					.getWorkbench().getSharedImages()
					.getImage(ISharedImages.IMG_LCL_LINKTO_HELP)));
		}

		@Override
		public void run() {
			final IWorkbenchHelpSystem helpSystem = PlatformUI.getWorkbench()
					.getHelpSystem();
			helpSystem.displayHelp("org.yakindu.sct.ui.editor.stext_keyword");
		};
	}

}