/*
 * 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.rya.indexing.external.matching;

import org.eclipse.rdf4j.query.algebra.Filter;
import org.eclipse.rdf4j.query.algebra.Join;
import org.eclipse.rdf4j.query.algebra.LeftJoin;
import org.eclipse.rdf4j.query.algebra.Projection;
import org.eclipse.rdf4j.query.algebra.TupleExpr;

public class MatcherUtilities {

    public static boolean segmentContainsLeftJoins(final TupleExpr tupleExpr) {
        if (tupleExpr instanceof Projection) {
            return segmentContainsLeftJoins(((Projection) tupleExpr).getArg());
        } else if (tupleExpr instanceof Join) {
            final Join join = (Join) tupleExpr;
            return segmentContainsLeftJoins(join.getRightArg())
                    || segmentContainsLeftJoins(join.getLeftArg());
        } else if (tupleExpr instanceof LeftJoin) {
            return true;
        } else if (tupleExpr instanceof Filter) {
            return segmentContainsLeftJoins(((Filter) tupleExpr).getArg());
        } else {
            return false;
        }
    }

}
