/*
 * Copyright (C) 2017-2019 Dremio Corporation
 *
 * Licensed 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 com.dremio.exec.planner.logical;

import org.apache.calcite.adapter.enumerable.EnumerableConvention;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.convert.ConverterRule;

/**
 * Rule that converts any Dremio relational expression to enumerable format by adding a {@link ScreenRelBase}.
 */
public class EnumerableRule extends ConverterRule {

  public static EnumerableRule INSTANCE = new EnumerableRule();


  private EnumerableRule() {
    super(RelNode.class, Rel.LOGICAL, EnumerableConvention.INSTANCE, "EnumerableRule.");
  }

  @Override
  public boolean isGuaranteed() {
    return true;
  }

  @Override
  public RelNode convert(RelNode rel) {
    assert rel.getTraitSet().contains(Rel.LOGICAL);
    return new ScreenRel(rel.getCluster(), rel.getTraitSet().replace(getOutConvention()), rel);
  }
}
