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.RelOptPredicateList;
  import org.apache.calcite.plan.RelOptRuleCall;
  import org.apache.calcite.plan.RelRule;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.Join;
  import org.apache.calcite.rel.core.RelFactories;
  import org.apache.calcite.rel.metadata.RelMetadataQuery;
  import org.apache.calcite.tools.RelBuilder;
  import org.apache.calcite.tools.RelBuilderFactory;
  
  import org.immutables.value.Value;
  
  /**
   * Planner rule that infers predicates from on a
   * {@link org.apache.calcite.rel.core.Join} and creates
   * {@link org.apache.calcite.rel.core.Filter}s if those predicates can be pushed
   * to its inputs.
   *
   * <p>Uses {@link org.apache.calcite.rel.metadata.RelMdPredicates} to infer
   * the predicates,
   * returns them in a {@link org.apache.calcite.plan.RelOptPredicateList}
   * and applies them appropriately.
   *
   * @see CoreRules#JOIN_PUSH_TRANSITIVE_PREDICATES
   */
  @Value.Enclosing
  public class JoinPushTransitivePredicatesRule
      extends RelRule<JoinPushTransitivePredicatesRule.Config>
      implements TransformationRule {
  
    /** Creates a JoinPushTransitivePredicatesRule. */
    protected JoinPushTransitivePredicatesRule(Config config) {
      super(config);
    }
  
    @Deprecated // to be removed before 2.0
    public JoinPushTransitivePredicatesRule(Class<? extends Join> joinClass,
        RelBuilderFactory relBuilderFactory) {
      this(Config.DEFAULT.withRelBuilderFactory(relBuilderFactory)
          .as(Config.class)
          .withOperandFor(joinClass));
    }
  
    @Deprecated // to be removed before 2.0
    public JoinPushTransitivePredicatesRule(Class<? extends Join> joinClass,
        RelFactories.FilterFactory filterFactory) {
      this(Config.DEFAULT
          .withRelBuilderFactory(RelBuilder.proto(Contexts.of(filterFactory)))
          .as(Config.class)
          .withOperandFor(joinClass));
    }
  
    @Override public void onMatch(RelOptRuleCall call) {
      Join join = call.rel(0);
      final RelMetadataQuery mq = call.getMetadataQuery();
      RelOptPredicateList preds = mq.getPulledUpPredicates(join);
  
      if (preds.leftInferredPredicates.isEmpty()
          && preds.rightInferredPredicates.isEmpty()) {
        return;
      }
  
      final RelBuilder relBuilder = call.builder();
  
      RelNode left = join.getLeft();
      if (!preds.leftInferredPredicates.isEmpty()) {
        RelNode curr = left;
        left = relBuilder.push(left)
            .filter(preds.leftInferredPredicates).build();
        call.getPlanner().onCopy(curr, left);
      }
  
      RelNode right = join.getRight();
      if (!preds.rightInferredPredicates.isEmpty()) {
        RelNode curr = right;
        right = relBuilder.push(right)
            .filter(preds.rightInferredPredicates).build();
        call.getPlanner().onCopy(curr, right);
      }
  
      RelNode newRel =
          join.copy(join.getTraitSet(), join.getCondition(), left, right,
              join.getJoinType(), join.isSemiJoinDone());
      call.getPlanner().onCopy(join, newRel);
  
      call.transformTo(newRel);
    }
  
    /** Rule configuration. */
    @Value.Immutable
    public interface Config extends RelRule.Config {
      Config DEFAULT = ImmutableJoinPushTransitivePredicatesRule.Config.of()
          .withOperandFor(Join.class);
  
      @Override default JoinPushTransitivePredicatesRule toRule() {
        return new JoinPushTransitivePredicatesRule(this);
      }
  
      /** Defines an operand tree for the given classes. */
      default Config withOperandFor(Class<? extends Join> joinClass) {
        return withOperandSupplier(b -> b.operand(joinClass).anyInputs())
            .as(Config.class);
      }
    }
  }
  