/*******************************************************************************
 * 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.db.common.request;

import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.exception.DatabaseException;

final public class PossibleObjectWithType extends ResourceRead3<Resource> {

    public PossibleObjectWithType(Resource resource, Resource predicate, Resource type) {
        super(resource, predicate, type);
    }

    @Override
    public Resource perform(ReadGraph graph) throws DatabaseException {
        Resource result = null;
        for(Resource object : graph.getObjects(resource, resource2)) {
            if(graph.isInstanceOf(object, resource3)) {
                if(result != null) return null;
                result = object;
            }
        }
        return result;
    }

}