| /* |
| * 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.sparql.algebra.op; |
| |
| import java.util.List ; |
| |
| import org.apache.jena.sparql.algebra.Op ; |
| import org.apache.jena.sparql.algebra.OpVisitor ; |
| import org.apache.jena.sparql.algebra.Transform ; |
| import org.apache.jena.sparql.sse.Tags ; |
| import org.apache.jena.sparql.util.NodeIsomorphismMap ; |
| |
| /** N-way disjunction. |
| * OpUnion remains as the strict SPARQL algebra operator. |
| */ |
| public class OpDisjunction extends OpN |
| { |
| public static OpDisjunction create() { return new OpDisjunction() ; } |
| |
| public static Op create(Op left, Op right) |
| { |
| // Avoid stages of nothing |
| if ( left == null && right == null ) |
| return null ; |
| // Avoid stages of one. |
| if ( left == null ) |
| return right ; |
| if ( right == null ) |
| return left ; |
| |
| if ( left instanceof OpDisjunction ) |
| { |
| OpDisjunction opDisjunction = (OpDisjunction)left ; |
| opDisjunction.add(right) ; |
| return opDisjunction ; |
| } |
| |
| // if ( right instanceof OpDisjunction ) |
| // { |
| // OpDisjunction opSequence = (OpDisjunction)right ; |
| // // Add front. |
| // opDisjunction.getElements().add(0, left) ; |
| // return opDisjunction ; |
| // } |
| |
| OpDisjunction stage = new OpDisjunction() ; |
| stage.add(left) ; |
| stage.add(right) ; |
| return stage ; |
| } |
| |
| private OpDisjunction(List<Op> elts) { super(elts) ; } |
| private OpDisjunction() { super() ; } |
| |
| @Override |
| public String getName() { return Tags.tagDisjunction ; } |
| |
| @Override |
| public void visit(OpVisitor opVisitor) |
| { opVisitor.visit(this) ; } |
| |
| @Override |
| public boolean equalTo(Op op, NodeIsomorphismMap labelMap) |
| { |
| if ( ! ( op instanceof OpDisjunction) ) return false ; |
| OpDisjunction other = (OpDisjunction) op ; |
| return super.equalsSubOps(other, labelMap) ; |
| } |
| |
| @Override |
| public Op apply(Transform transform, List<Op> elts) |
| { return transform.transform(this, elts) ; } |
| |
| @Override |
| public OpN copy(List<Op> elts) |
| { |
| return new OpDisjunction(elts) ; |
| } |
| } |