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.Contexts;
  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.RelFactories;
  import org.apache.calcite.tools.RelBuilder;
  import org.apache.calcite.tools.RelBuilderFactory;
  
  import org.immutables.value.Value;
  
  /**
   * Planner rule that combines two
   * {@link org.apache.calcite.rel.logical.LogicalFilter}s.
   */
  @Value.Enclosing
  public class FilterMergeRule extends RelRule<FilterMergeRule.Config>
      implements SubstitutionRule {
  
    /** Creates a FilterMergeRule. */
    protected FilterMergeRule(Config config) {
      super(config);
    }
  
    @Deprecated // to be removed before 2.0
    public FilterMergeRule(RelBuilderFactory relBuilderFactory) {
      this(Config.DEFAULT
          .withRelBuilderFactory(relBuilderFactory)
          .as(Config.class));
    }
  
    @Deprecated // to be removed before 2.0
    public FilterMergeRule(RelFactories.FilterFactory filterFactory) {
      this(RelBuilder.proto(Contexts.of(filterFactory)));
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public void onMatch(RelOptRuleCall call) {
      final Filter topFilter = call.rel(0);
      final Filter bottomFilter = call.rel(1);
  
      final RelBuilder relBuilder = call.builder();
      relBuilder.push(bottomFilter.getInput())
          .filter(bottomFilter.getCondition(), topFilter.getCondition());
  
      call.transformTo(relBuilder.build());
    }
  
    /** Rule configuration. */
    @Value.Immutable
    public interface Config extends RelRule.Config {
      Config DEFAULT = ImmutableFilterMergeRule.Config.of()
          .withOperandFor(Filter.class);
  
      @Override default FilterMergeRule toRule() {
        return new FilterMergeRule(this);
      }
  
      /** Defines an operand tree for the given classes. */
      default Config withOperandFor(Class<? extends Filter> filterClass) {
        return withOperandSupplier(b0 ->
            b0.operand(filterClass).oneInput(b1 ->
                b1.operand(filterClass).anyInputs()))
            .as(Config.class);
      }
    }
  }
  