com.hazelcast.org.apache.calcite.rel.rules.JoinPushExpressionsRule Maven / Gradle / Ivy

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/*
 * 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 com.hazelcast.org.apache.calcite.rel.rules;

import com.hazelcast.org.apache.calcite.plan.RelOptRuleCall;
import com.hazelcast.org.apache.calcite.plan.RelOptUtil;
import com.hazelcast.org.apache.calcite.plan.RelRule;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.core.Join;
import com.hazelcast.org.apache.calcite.rel.core.RelFactories;
import com.hazelcast.org.apache.calcite.rex.RexNode;
import com.hazelcast.org.apache.calcite.tools.RelBuilder;
import com.hazelcast.org.apache.calcite.tools.RelBuilderFactory;

import org.immutables.value.Value;

/**
 * Planner rule that pushes down expressions in "equal" join condition.
 *
 * For example, given
 * "emp JOIN dept ON emp.deptno + 1 = dept.deptno", adds a project above
 * "emp" that computes the expression
 * "emp.deptno + 1". The resulting join condition is a simple combination
 * of AND, equals, and input fields, plus the remaining non-equal conditions.
 *
 * @see CoreRules#JOIN_PUSH_EXPRESSIONS
 */
@Value.Enclosing
public class JoinPushExpressionsRule
    extends RelRule
    implements TransformationRule {

  /** Creates a JoinPushExpressionsRule. */
  protected JoinPushExpressionsRule(Config config) {
    super(config);
  }

  @Deprecated // to be removed before 2.0
  public JoinPushExpressionsRule(Class joinClass,
      RelBuilderFactory relBuilderFactory) {
    this(Config.DEFAULT.withRelBuilderFactory(relBuilderFactory)
        .as(Config.class)
        .withOperandFor(joinClass));
  }

  @Deprecated // to be removed before 2.0
  public JoinPushExpressionsRule(Class joinClass,
      RelFactories.ProjectFactory projectFactory) {
    this(Config.DEFAULT.withRelBuilderFactory(RelBuilder.proto(projectFactory))
        .as(Config.class)
        .withOperandFor(joinClass));
  }

  @Override public void onMatch(RelOptRuleCall call) {
    Join join = call.rel(0);

    // Push expression in join condition into Project below Join.
    RelNode newJoin = RelOptUtil.pushDownJoinConditions(join, call.builder());

    // If the join is the same, we bail out
    if (newJoin instanceof Join) {
      final RexNode newCondition = ((Join) newJoin).getCondition();
      if (join.getCondition().equals(newCondition)) {
        return;
      }
    }

    call.transformTo(newJoin);
  }

  /** Rule configuration. */
  @Value.Immutable
  public interface Config extends RelRule.Config {
    Config DEFAULT = ImmutableJoinPushExpressionsRule.Config.of()
        .withOperandFor(Join.class);

    @Override default JoinPushExpressionsRule toRule() {
      return new JoinPushExpressionsRule(this);
    }

    /** Defines an operand tree for the given classes. */
    default Config withOperandFor(Class joinClass) {
      return withOperandSupplier(b -> b.operand(joinClass).anyInputs())
          .as(Config.class);
    }
  }
}