/*
 * (c) Copyright 2008, 2009 Hewlett-Packard Development Company, LP
 * All rights reserved.
 * [See end of file]
 */

package dev.opt;

import java.util.Iterator;

import com.hp.hpl.jena.sparql.algebra.Op;
import com.hp.hpl.jena.sparql.algebra.OpVisitor;
import com.hp.hpl.jena.sparql.algebra.OpVisitorByType;
import com.hp.hpl.jena.sparql.algebra.op.Op0;
import com.hp.hpl.jena.sparql.algebra.op.Op1;
import com.hp.hpl.jena.sparql.algebra.op.Op2;
import com.hp.hpl.jena.sparql.algebra.op.OpExt;
import com.hp.hpl.jena.sparql.algebra.op.OpN;

/** Apply a visitor to the whole structure of Ops, recursively (do current level before sub Op) */

public class OpWalkerDown
 {
     public static void walk(Op op, OpVisitor visitor)
     {
         op.visit(new WalkerDownVisitor(visitor, null, null)) ;
     }
     
     private static class WalkerDownVisitor extends OpVisitorByType
     {
         private OpVisitor beforeVisitor = null ;
         private OpVisitor afterVisitor  = null ;
         private OpVisitor visitor ;

         public WalkerDownVisitor(OpVisitor visitor, OpVisitor beforeVisitor, OpVisitor afterVisitor)
         {
             this(visitor) ;
             this.beforeVisitor = beforeVisitor ;
             this.afterVisitor = afterVisitor ;
         }

         public WalkerDownVisitor(OpVisitor visitor)
         {
             this.visitor = visitor ;
         }

         private void before(Op op)
         {
             if (beforeVisitor != null) op.visit(beforeVisitor) ;
         }

         private void after(Op op)
         {
             if (afterVisitor != null) op.visit(afterVisitor) ;
         }

         @Override
         protected void visitN(OpN op)
         {
             before(op) ;
             if (visitor != null) op.visit(visitor) ;
             for (Iterator<? > iter = op.iterator(); iter.hasNext();)
             {
                 Op sub = (Op)iter.next() ;
                 sub.visit(this) ;
             }
             after(op) ;
         }

         @Override
         protected void visit2(Op2 op)
         {
             before(op) ;
             if (visitor != null) op.visit(visitor) ;
             if (op.getLeft() != null) op.getLeft().visit(this) ;
             if (op.getRight() != null) op.getRight().visit(this) ;
             after(op) ;
         }

         @Override
         protected void visit1(Op1 op)
         {
             before(op) ;
             if (visitor != null) op.visit(visitor) ;
             if (op.getSubOp() != null) op.getSubOp().visit(this) ;
             after(op) ;
         }

         @Override
         protected void visit0(Op0 op)
         {
             before(op) ;
             if (visitor != null) op.visit(visitor) ;
             after(op) ;
         }

         @Override
         protected void visitExt(OpExt op)
         {
             before(op) ;
             if (visitor != null) op.visit(visitor) ;
             after(op) ;
         }
     }
 }
/*
 * (c) Copyright 2008, 2009 Hewlett-Packard Development Company, LP
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */