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.Filter;
  import org.apache.calcite.rel.core.Join;
  import org.apache.calcite.rel.core.JoinRelType;
  import org.apache.calcite.rel.core.RelFactories;
  import org.apache.calcite.rel.logical.LogicalFilter;
  import org.apache.calcite.rel.logical.LogicalJoin;
  import org.apache.calcite.tools.RelBuilderFactory;
  
  import com.google.common.collect.ImmutableList;
  import com.google.common.collect.ImmutableSet;
  
  import org.immutables.value.Value;
  
  /**
   * Planner rule that pushes {@code SemiJoin}s down in a tree past
   * a {@link org.apache.calcite.rel.core.Filter}.
   *
   * <p>The intention is to trigger other rules that will convert
   * {@code SemiJoin}s.
   *
   * <p>SemiJoin(LogicalFilter(X), Y) &rarr; LogicalFilter(SemiJoin(X, Y))
   *
   * @see SemiJoinProjectTransposeRule
   * @see CoreRules#SEMI_JOIN_FILTER_TRANSPOSE
   */
  @Value.Enclosing
  public class SemiJoinFilterTransposeRule
      extends RelRule<SemiJoinFilterTransposeRule.Config>
      implements TransformationRule {
  
    /** Creates a SemiJoinFilterTransposeRule. */
    protected SemiJoinFilterTransposeRule(Config config) {
      super(config);
    }
  
    @Deprecated // to be removed before 2.0
    public SemiJoinFilterTransposeRule(RelBuilderFactory relBuilderFactory) {
      this(Config.DEFAULT.withRelBuilderFactory(relBuilderFactory)
          .as(Config.class));
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public void onMatch(RelOptRuleCall call) {
      final Join semiJoin = call.rel(0);
      final Filter filter = call.rel(1);
  
      final RelNode newSemiJoin =
          LogicalJoin.create(filter.getInput(),
              semiJoin.getRight(),
              // No need to copy the hints, the framework would try to do that.
              ImmutableList.of(),
              semiJoin.getCondition(),
              ImmutableSet.of(),
              JoinRelType.SEMI);
  
      final RelFactories.FilterFactory factory =
          RelFactories.DEFAULT_FILTER_FACTORY;
      RelNode newFilter =
          factory.createFilter(newSemiJoin, filter.getCondition(),
              ImmutableSet.of());
  
      call.transformTo(newFilter);
    }
  
    /** Rule configuration. */
    @Value.Immutable
    public interface Config extends RelRule.Config {
      Config DEFAULT = ImmutableSemiJoinFilterTransposeRule.Config.of()
          .withOperandFor(LogicalJoin.class, LogicalFilter.class);
  
      @Override default SemiJoinFilterTransposeRule toRule() {
        return new SemiJoinFilterTransposeRule(this);
      }
  
      /** Defines an operand tree for the given classes. */
      default Config withOperandFor(Class<? extends Join> joinClass,
          Class<? extends Filter> filterClass) {
        return withOperandSupplier(b0 ->
            b0.operand(joinClass).predicate(Join::isSemiJoin).inputs(b1 ->
                b1.operand(filterClass).anyInputs()))
            .as(Config.class);
      }
    }
  }
  