content: /*
   * 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.calcite.rel.rules;
  
  import org.apache.calcite.plan.RelOptRuleCall;
  import org.apache.calcite.plan.RelRule;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.Calc;
  import org.apache.calcite.rel.logical.LogicalCalc;
  import org.apache.calcite.tools.RelBuilderFactory;
  
  import org.immutables.value.Value;
  
  /**
   * Planner rule that removes a trivial
   * {@link org.apache.calcite.rel.logical.LogicalCalc}.
   *
   * <p>A {@link org.apache.calcite.rel.logical.LogicalCalc}
   * is trivial if it projects its input fields in their
   * original order, and it does not filter.
   *
   * @see ProjectRemoveRule
   */
  @Value.Enclosing
  public class CalcRemoveRule extends RelRule<CalcRemoveRule.Config>
      implements SubstitutionRule {
  
    /** Creates a CalcRemoveRule. */
    protected CalcRemoveRule(Config config) {
      super(config);
    }
  
    @Deprecated // to be removed before 2.0
    public CalcRemoveRule(RelBuilderFactory relBuilderFactory) {
      this(Config.DEFAULT.withRelBuilderFactory(relBuilderFactory)
          .as(Config.class));
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public void onMatch(RelOptRuleCall call) {
      final Calc calc = call.rel(0);
      assert calc.getProgram().isTrivial() : "rule predicate";
      RelNode input = calc.getInput();
      input = call.getPlanner().register(input, calc);
      call.transformTo(
          convert(
              call.getPlanner(),
              input,
              calc.getTraitSet()));
    }
  
    /** Rule configuration. */
    @Value.Immutable
    public interface Config extends RelRule.Config {
      Config DEFAULT = ImmutableCalcRemoveRule.Config.of()
          .withOperandSupplier(b ->
              b.operand(LogicalCalc.class)
                  .predicate(calc -> calc.getProgram().isTrivial())
                  .anyInputs())
          .as(Config.class);
  
      @Override default CalcRemoveRule toRule() {
        return new CalcRemoveRule(this);
      }
    }
  }
  