/*******************************************************************************
 * Copyright (c) 2007, 2018 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.layer0.request;

import org.simantics.datatypes.literal.GUID;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.ResourceRead;
import org.simantics.db.exception.DatabaseException;
import org.simantics.layer0.Layer0;

public class PossibleGUID extends ResourceRead<String> {

    public PossibleGUID(Resource resource) {
        super(resource);
    }

    @Override
    public String perform(ReadGraph graph) throws DatabaseException {
        Layer0 L0 = Layer0.getInstance(graph);
        GUID guid = graph.getPossibleRelatedValue(resource, L0.identifier, GUID.BINDING);
        return guid != null ? guid.indexString() : null;
    }

}