/*******************************************************************************
* 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.uri;
import org.simantics.databoard.Bindings;
import org.simantics.databoard.util.URIStringUtils;
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;
/**
* Tries to retrieve URIs for specified resources. Returns null
if
* URI is undefined. This query follows the semantics of
* {@link ReadGraph#getPossibleURI(Resource)}.
*
* @author Antti Villberg
*/
public class ResourceToPossibleURI extends ResourceRead {
public ResourceToPossibleURI(Resource resource) {
super(resource);
}
@Override
public String perform(ReadGraph g) throws DatabaseException {
if(g.getRootLibrary().equals(resource)) return "http:/";
Layer0 L0 = Layer0.getInstance(g);
String name = g.getPossibleRelatedValue(resource, L0.HasName, Bindings.STRING);
if(name == null) return null;
String escapedName = URIStringUtils.escape((String) name);
Resource parent = g.getPossibleObject(resource, L0.PartOf);
if(parent == null) return null;
String parentURI = g.syncRequest(new ResourceToPossibleURI(parent));
if(parentURI == null) return null;
return parentURI + "/" + escapedName;
}
}