package org.simantics.db.layer0.request;

import java.util.Collection;

import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.SingletonRead;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.util.Layer0Utils;

/**
 * Returns a set of index roots.
 * 
 * @author Antti Villberg
 */
public class ListIndexRoots extends SingletonRead<Collection<Resource>> {

    public ListIndexRoots() {
    }

    @Override
    public Collection<Resource> perform(ReadGraph graph) throws DatabaseException {
    	return Layer0Utils.listIndexRoots(graph);
    }

}