/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * 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:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.layer0.utils.collections;

import java.util.Collection;

import org.simantics.db.Resource;
import org.simantics.db.ReadGraph;
import org.simantics.db.exception.DatabaseException;
import org.simantics.layer0.utils.operations.IOperation;
import org.simantics.layer0.utils.predicates.IUnaryPredicate;
import org.simantics.utils.datastructures.persistent.IContextMap;

public class ConditionalList implements IContextualList {

	IUnaryPredicate predicate;
	Resource thenElement;
	Resource elseElement;

	public ConditionalList(IUnaryPredicate predicate, Resource thenElement,
			Resource elseElement) {
		this.predicate = predicate;
		this.thenElement = thenElement;
		this.elseElement = elseElement;
	}

	@Override
	public void fill(ReadGraph g, IContextMap parameters, Collection<Resource> c) throws DatabaseException {
		Resource r = (Resource)parameters.get(IOperation.SUBJECT);
		
		if(predicate.has(g, r))
			ContextualListUtils.fill(g, thenElement, parameters, c);
		else if(elseElement != null)
			ContextualListUtils.fill(g, elseElement, parameters, c);
	}

}