| /* |
| * 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; |
| |
| import java.util.Iterator ; |
| |
| import org.apache.jena.sparql.algebra.op.* ; |
| |
| /** Apply a visitor to the whole structure of Ops, recursively. |
| * Visit sub Op before the current level |
| */ |
| |
| public class OpWalker |
| { |
| // Predates org.apache.jena.sparql.algebra.walker.Walker |
| // Need to convert but OpVars depends on OpWalkerVisitorFixed, OpWalkerVisitorVisible |
| |
| /* OpVars:: |
| public static void visibleVars(Op op, Set<Var> acc) { |
| OpVarsPattern visitor = new OpVarsPattern(acc, true) ; |
| // Does not work. |
| //new WalkerVisitorVisible(visitor, null, null, null).walk(op); |
| //OpWalker.walk(new OpWalkerVisitorVisible(visitor, acc), op) ; |
| } |
| */ |
| |
| // **** Replace with org.apache.jena.sparql.algebra.walker.Walker |
| public static void walk(Op op, OpVisitor visitor) |
| { |
| // new walker :: this works |
| // Walker.walk(op, visitor); |
| walk(new OpWalkerVisitor(visitor, null, null), op) ; |
| } |
| |
| // public static void walk(Op op, OpVisitor visitor, OpVisitor beforeVisitor, OpVisitor afterVisitor) |
| // { |
| // walk(new OpWalkerVisitor(visitor, beforeVisitor, afterVisitor), op) ; |
| // } |
| |
| public static void walk(OpWalkerVisitor walkerVisitor, Op op) |
| { |
| // Stil needed for OpWalkerVisitorVisible, OpWalkerVisitorFixed |
| op.visit(walkerVisitor) ; |
| } |
| |
| protected static class OpWalkerVisitor extends OpVisitorByType { |
| private final OpVisitor beforeVisitor ; |
| private final OpVisitor afterVisitor ; |
| protected final OpVisitor visitor ; |
| |
| public OpWalkerVisitor(OpVisitor visitor, OpVisitor beforeVisitor, OpVisitor afterVisitor) { |
| this.visitor = visitor ; |
| this.beforeVisitor = beforeVisitor ; |
| this.afterVisitor = afterVisitor ; |
| } |
| |
| public OpWalkerVisitor(OpVisitor visitor) { |
| this(visitor, null, null) ; |
| } |
| |
| protected final void before(Op op) { |
| if ( beforeVisitor != null ) |
| op.visit(beforeVisitor) ; |
| } |
| |
| protected final void after(Op op) { |
| if ( afterVisitor != null ) |
| op.visit(afterVisitor) ; |
| } |
| |
| @Override |
| protected void visit0(Op0 op) { |
| before(op) ; |
| if ( visitor != null ) |
| op.visit(visitor) ; |
| after(op) ; |
| } |
| |
| @Override |
| protected void visit1(Op1 op) { |
| before(op) ; |
| if ( op.getSubOp() != null ) |
| op.getSubOp().visit(this) ; |
| if ( visitor != null ) |
| op.visit(visitor) ; |
| after(op) ; |
| } |
| |
| @Override |
| protected void visitFilter(OpFilter op) { |
| visit1(op) ; |
| } |
| |
| @Override |
| protected void visitLeftJoin(OpLeftJoin op) { |
| visit2(op) ; |
| } |
| |
| @Override |
| protected void visit2(Op2 op) { |
| before(op) ; |
| if ( op.getLeft() != null ) |
| op.getLeft().visit(this) ; |
| if ( op.getRight() != null ) |
| op.getRight().visit(this) ; |
| if ( visitor != null ) |
| op.visit(visitor) ; |
| after(op) ; |
| } |
| |
| @Override |
| protected void visitN(OpN op) { |
| before(op) ; |
| for (Iterator<Op> iter = op.iterator(); iter.hasNext();) { |
| Op sub = iter.next() ; |
| sub.visit(this) ; |
| } |
| if ( visitor != null ) |
| op.visit(visitor) ; |
| after(op) ; |
| } |
| |
| @Override |
| protected void visitExt(OpExt op) { |
| before(op) ; |
| if ( op.effectiveOp() != null ) |
| // Walk the effective op, if present. |
| op.effectiveOp().visit(this); |
| if ( visitor != null ) |
| op.visit(visitor) ; |
| after(op) ; |
| } |
| } |
| } |