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.Filter;
  import org.apache.calcite.rel.core.Sample;
  import org.apache.calcite.tools.RelBuilder;
  
  import org.immutables.value.Value;
  
  /**
   * Planner rule that pushes
   * a {@link org.apache.calcite.rel.core.Filter}
   * past a {@link org.apache.calcite.rel.core.Sample}.
   *
   * @see CoreRules#FILTER_SAMPLE_TRANSPOSE
   */
  @Value.Enclosing
  public class FilterSampleTransposeRule
      extends RelRule<FilterSampleTransposeRule.Config>
      implements TransformationRule {
  
    protected FilterSampleTransposeRule(Config config) {
      super(config);
    }
  
    @Override public void onMatch(final RelOptRuleCall call) {
      final Filter filter = call.rel(0);
      final Sample sample = call.rel(1);
      final RelBuilder relBuilder = call.builder();
      // Push filter condition past the Sample.
      relBuilder.push(sample.getInput());
      relBuilder.filter(filter.getCondition());
      // Build the sample on top of the filter.
      relBuilder.sample(sample.getSamplingParameters().isBernoulli(),
          sample.getSamplingParameters().sampleRate,
          sample.getSamplingParameters().getRepeatableSeed());
      call.transformTo(relBuilder.build());
    }
  
    /** Rule configuration. */
    @Value.Immutable
    public interface Config extends RelRule.Config {
      Config DEFAULT = ImmutableFilterSampleTransposeRule.Config.of()
          .withOperandSupplier(b0 ->
              b0.operand(Filter.class).oneInput(b1 ->
                  b1.operand(Sample.class).anyInputs()));
  
      @Override default FilterSampleTransposeRule toRule() {
        return new FilterSampleTransposeRule(this);
      }
    }
  }
  