exec/java-exec/src/main/java/org/apache/drill/exec/planner/physical/visitor/ProducerConsumerPrelVisitor.java

/*
 * 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.drill.exec.planner.physical.visitor;

import java.util.List;

import org.apache.drill.exec.planner.physical.Prel;
import org.apache.drill.exec.planner.physical.ProducerConsumerPrel;
import org.apache.drill.exec.planner.physical.ScanPrel;
import org.apache.calcite.rel.RelNode;

import com.google.common.collect.Lists;


public class ProducerConsumerPrelVisitor extends BasePrelVisitor<Prel, Void, RuntimeException>{

  private int queueSize;

  public static Prel addProducerConsumerToScans(Prel prel, int queueSize){

    return prel.accept(new ProducerConsumerPrelVisitor(queueSize), null);
  }

  public ProducerConsumerPrelVisitor(int queueSize) {
    this.queueSize = queueSize;
  }

  @Override
  public Prel visitPrel(Prel prel, Void value) throws RuntimeException {
    List<RelNode> children = Lists.newArrayList();
    for(Prel child : prel){
      children.add(child.accept(this, null));
    }
    return (Prel) prel.copy(prel.getTraitSet(), children);
  }

  @Override
  public Prel visitScan(ScanPrel scanPrel, Void value) {
    return new ProducerConsumerPrel(scanPrel, queueSize);
  }


}