Start line:  
End line:  

Snippet Preview

Snippet HTML Code

Stack Overflow Questions
 /*
  * 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.pig.newplan;
Do a depth first traversal of the graph.
public class DepthFirstWalker extends PlanWalker {
    public DepthFirstWalker(OperatorPlan plan) {
        super(plan);
    }
    @Override
    public PlanWalker spawnChildWalker(OperatorPlan plan) {
        return new DepthFirstWalker(plan);
    }

    
Begin traversing the graph.

Parameters:
visitor Visitor this walker is being used by.
Throws:
org.apache.pig.impl.logicalLayer.FrontendException if an error is encountered while walking.
    @Override
    public void walk(PlanVisitor visitorthrows FrontendException {
        List<Operatorroots = .getSources();
        Set<Operatorseen = new HashSet<Operator>();
        depthFirst(nullrootsseenvisitor);
    }
    private void depthFirst(Operator node,
                            Collection<Operatorsuccessors,
                            Set<Operatorseen,
                            PlanVisitor visitorthrows FrontendException {
        if (successors == nullreturn;
        for (Operator suc : successors) {
            if (seen.add(suc)) {
                suc.accept(visitor);
                Collection<OperatornewSuccessors = Utils.mergeCollection(.getSuccessors(suc), .getSoftLinkSuccessors(suc));
                depthFirst(sucnewSuccessorsseenvisitor);
            }
        }
    }
New to GrepCode? Check out our FAQ X