plugins/org.eclipse.viatra2.visualisation/src/org/eclipse/viatra2/visualisation/common/filters/TypeBasedFilter.java

/*******************************************************************************
 * Copyright (c) 2011, Istvan Rath, Zoltan Ujhelyi, Daniel Varro
 * 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:
 *   Istvan Rath - initial API and implementation
 *******************************************************************************/

package org.eclipse.viatra2.visualisation.common.filters;

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

import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.viatra2.core.IModelElement;
import org.eclipse.viatra2.core.IModelManager;
import org.eclipse.viatra2.core.IModelSpace;

/**
 * Type-based abstract viewer filter, provides facilities
 * to filter the model space view according to a given set of
 *  - allowed
 *  - disallowed
 * VPM types.
 * 
 * @author Istvan Rath
 *
 */
public abstract class TypeBasedFilter extends ViewerFilter {
	
	protected final static List<String> allowedTypeIDs = new ArrayList<String>();
	
	protected final static List<String> disallowedTypeIDs = new ArrayList<String>();
	
	/**
	 * hash used to detect when the filter is being used for a different modelspace than previously.
	 */
	int modelSpaceHash;

	@Override
	public final boolean select(Viewer viewer, Object parentElement, Object element) {
		if (element instanceof IModelElement) {
			IModelElement modelElement = (IModelElement) element;
			IModelSpace ms = modelElement.getModelSpace();
			IModelManager mm = ms.getModelManager();
			
			if(!allowedTypeIDs.isEmpty() && ms.hashCode() != modelSpaceHash){
				modelSpaceHash = ms.hashCode();
				allowedTypeIDs.clear();
			}
			if(allowedTypeIDs.isEmpty()){
				fillAllowedTypeIDs(mm);
			}
			if(!disallowedTypeIDs.isEmpty() && ms.hashCode() != modelSpaceHash){
				modelSpaceHash = ms.hashCode();
				allowedTypeIDs.clear();
			}
			if(disallowedTypeIDs.isEmpty()){
				fillDisallowedTypeIDs(mm);
			}
			if (!allowedTypeIDs.isEmpty()) {
				for (String typeId : allowedTypeIDs) {
					IModelElement type = mm.getElementByID(typeId);
					if (modelElement.isInstanceOf(type)) {
						return true;
					}
				}
				return false;
			}
			else if (!disallowedTypeIDs.isEmpty()) {
				for (String typeId : disallowedTypeIDs) {
					IModelElement type = mm.getElementByID(typeId);
					if (modelElement.isInstanceOf(type)) {
						return false;
					}
				}
				return true;
			}
		}
		return true;
	}

	protected abstract void fillAllowedTypeIDs(IModelManager manager);
	
	protected abstract void fillDisallowedTypeIDs(IModelManager manager);
	
}