/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.tdb.migrate;

import org.apache.jena.sparql.algebra.Op ;
import org.apache.jena.sparql.algebra.Transform ;
import org.apache.jena.sparql.algebra.Transformer ;
import org.apache.jena.sparql.core.Quad ;

public class A2
{
    /** Convert a pattern, assumed to be quad form, 
     * so that the default graph is the union of named graphs.  
     */
    public static Op unionDefaultGraphQuads(Op op)
    {
        // Rewrite so that any explicitly named "default graph" is union graph.
        Transform t = new TransformGraphRename(Quad.defaultGraphNodeGenerated, Quad.unionGraph)  ;
        op = Transformer.transform(t, op) ;
        return op ;
    }
}
