exec/java-exec/src/main/java/org/apache/drill/exec/planner/physical/ScreenPrule.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
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 */
package org.apache.drill.exec.planner.physical;

import org.apache.drill.exec.planner.common.DrillScreenRelBase;
import org.apache.drill.exec.planner.logical.DrillRel;
import org.apache.drill.exec.planner.logical.DrillScreenRel;
import org.apache.drill.exec.planner.logical.RelOptHelper;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.plan.RelOptRule;
import org.apache.calcite.plan.RelOptRuleCall;
import org.apache.calcite.plan.RelTraitSet;

public class ScreenPrule extends Prule{
  public static final RelOptRule INSTANCE = new ScreenPrule();


  public ScreenPrule() {
    super(RelOptHelper.some(DrillScreenRel.class, DrillRel.DRILL_LOGICAL, RelOptHelper.any(RelNode.class)), "Prel.ScreenPrule");
  }

  @Override
  public void onMatch(RelOptRuleCall call) {
    final DrillScreenRelBase screen = call.rel(0);
    final RelNode input = call.rel(1);

    final RelTraitSet traits = input.getTraitSet().plus(Prel.DRILL_PHYSICAL).plus(DrillDistributionTrait.SINGLETON);
    final RelNode convertedInput = convert(input, traits);
    DrillScreenRelBase newScreen = new ScreenPrel(screen.getCluster(), screen.getTraitSet().plus(Prel.DRILL_PHYSICAL).plus(DrillDistributionTrait.SINGLETON), convertedInput);
    call.transformTo(newScreen);
  }
}