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.core.Calc;
  import org.apache.calcite.rel.core.Filter;
  import org.apache.calcite.rel.logical.LogicalCalc;
  import org.apache.calcite.rex.RexBuilder;
  import org.apache.calcite.rex.RexProgram;
  import org.apache.calcite.rex.RexProgramBuilder;
  import org.apache.calcite.rex.RexUtil;
  import org.apache.calcite.tools.RelBuilderFactory;
  
  import org.immutables.value.Value;
  
  /**
   * Planner rule that merges a
   * {@link org.apache.calcite.rel.core.Filter} and a
   * {@link org.apache.calcite.rel.core.Calc}. The
   * result is a {@link org.apache.calcite.rel.core.Calc}
   * whose filter condition is the logical AND of the two.
   *
   * @see FilterMergeRule
   * @see ProjectCalcMergeRule
   * @see CoreRules#FILTER_CALC_MERGE
   */
  @Value.Enclosing
  public class FilterCalcMergeRule
      extends RelRule<FilterCalcMergeRule.Config>
      implements TransformationRule {
  
    /** Creates a FilterCalcMergeRule. */
    protected FilterCalcMergeRule(Config config) {
      super(config);
    }
  
    @Deprecated // to be removed before 2.0
    public FilterCalcMergeRule(RelBuilderFactory relBuilderFactory) {
      this(Config.DEFAULT
          .withRelBuilderFactory(relBuilderFactory)
          .as(Config.class));
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public void onMatch(RelOptRuleCall call) {
      final Filter filter = call.rel(0);
      final Calc calc = call.rel(1);
  
      // Don't merge a filter onto a calc which contains windowed aggregates.
      // That would effectively be pushing a multiset down through a filter.
      // We'll have chance to merge later, when the over is expanded.
      if (calc.containsOver()) {
        return;
      }
  
      // Create a program containing the filter.
      final RexBuilder rexBuilder = filter.getCluster().getRexBuilder();
      final RexProgramBuilder progBuilder =
          new RexProgramBuilder(
              calc.getRowType(),
              rexBuilder);
      progBuilder.addIdentity();
      progBuilder.addCondition(filter.getCondition());
      RexProgram topProgram = progBuilder.getProgram();
      RexProgram bottomProgram = calc.getProgram();
  
      // Merge the programs together.
      RexProgram mergedProgram =
          RexProgramBuilder.mergePrograms(
              topProgram,
              bottomProgram,
              rexBuilder);
      final Calc newCalc =
          calc.copy(calc.getTraitSet(), calc.getInput(), mergedProgram);
      call.transformTo(newCalc);
    }
  
    /** Rule configuration. */
    @Value.Immutable
    public interface Config extends RelRule.Config {
      Config DEFAULT = ImmutableFilterCalcMergeRule.Config.of()
          .withOperandFor(Filter.class, LogicalCalc.class);
  
      @Override default FilterCalcMergeRule toRule() {
        return new FilterCalcMergeRule(this);
      }
  
      /** Defines an operand tree for the given classes. */
      default Config withOperandFor(Class<? extends Filter> filterClass,
          Class<? extends Calc> calcClass) {
        return withOperandSupplier(b0 ->
            b0.operand(filterClass)
                .predicate(filter -> !RexUtil.SubQueryFinder.containsSubQuery(filter))
                .oneInput(b1 -> b1.operand(calcClass).anyInputs()))
            .as(Config.class);
      }
    }
  }
  