org.eclipse.emf.refactor.smells.xtext/src/org/eclipse/emf/refactor/smells/xtext/managers/XtextHighlightManager.java

package org.eclipse.emf.refactor.smells.xtext.managers;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.refactor.smells.runtime.core.EObjectGroup;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.xtext.nodemodel.ICompositeNode;
import org.eclipse.xtext.nodemodel.util.NodeModelUtils;
import org.eclipse.xtext.ui.editor.XtextEditor;
import org.eclipse.xtext.ui.editor.utils.EditorUtils;

import com.google.inject.Inject;

public class XtextHighlightManager {
	
	private static XtextHighlightManager instance = null;	
	private List<EObject> selected; 
	
	private XtextHighlightManager() {
		selected = new ArrayList<EObject>();
	}
	
	public static XtextHighlightManager getInstance() {
		if(instance == null) {
			instance = new XtextHighlightManager();
		}
		return instance;
	}
	
	@Inject 
	public void highlight(Object selection) {
		// clear former selected eObjects
		selected.clear();
		// set selected eObjects from selection
		if (selection instanceof EObjectGroup) {			
			selected.addAll(((EObjectGroup) selection).getEObjects());
		}
		if (selection instanceof EObject) {
			selected.add((EObject) selection);
		}
		// highlight each eObject in editor
		for (EObject eObject : selected) {
			XtextEditor xEditor = EditorUtils.getActiveXtextEditor();
			ICompositeNode node = NodeModelUtils.findActualNodeFor(eObject);
    		int offset = node.getOffset();
			int length = node.getLength();
    		ISourceViewer textViewer = xEditor.getInternalSourceViewer();
			textViewer.setRangeIndication(offset, length, true);
			textViewer.revealRange(offset, length);
			textViewer.setSelectedRange(offset, length);
		}
	}

	public List<EObject> getSelected() {
		return selected;
	}		
}