/**
 * 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 arq.examples.bgpmatching;

import org.apache.jena.sparql.ARQNotImplemented ;
import org.apache.jena.sparql.algebra.op.OpBGP ;
import org.apache.jena.sparql.algebra.op.OpDatasetNames ;
import org.apache.jena.sparql.algebra.op.OpQuadPattern ;
import org.apache.jena.sparql.engine.ExecutionContext ;
import org.apache.jena.sparql.engine.QueryIterator ;
import org.apache.jena.sparql.engine.main.OpExecutor ;
import org.apache.jena.sparql.engine.main.OpExecutorFactory ;

/** Example of an alternative OpExecutor */
public class OpExecutorAlt extends OpExecutor {

    public static OpExecutorFactory factory = new OpExecutorFactory() {

        @Override
        public OpExecutor create(ExecutionContext execCxt) {
            return new OpExecutorAlt(execCxt) ;
        }} ;

        
    public OpExecutorAlt(ExecutionContext execCxt) {
        super(execCxt) ;
    }
    
    // The two places where we touch the storage, dpeneding on whether this is a
    // triple or a quad based execution.
    
    @Override
    protected QueryIterator execute(OpBGP opBGP, QueryIterator input) {
        return super.execute(opBGP, input) ;
    }
    
    // Default OpQuadPattern execution is a loop and it will call back into
    // execute(OpBGP, QueryIterator)
    @Override
    protected QueryIterator execute(OpQuadPattern opQuadPattern, QueryIterator input) {
        return super.execute(opQuadPattern, input) ;
    }

    // Quad form, "GRAPH ?g {}" 
    // Flip back to OpGraph.
    // Not needed for triples-based execution 
    // Normally quad stores override this.
    @Override
    protected QueryIterator execute(OpDatasetNames dsNames, QueryIterator input) {
        throw new ARQNotImplemented("execute/OpDatasetNames") ;
    }
}