core/src/main/java/org/apache/calcite/plan/CommonRelSubExprRule.java

/*
 * 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.plan;

/**
 * A <code>CommonRelSubExprRule</code> is an abstract base class for rules
 * that are fired only on relational expressions that appear more than once
 * in a query tree.
 */

// TODO: obsolete this?
public abstract class CommonRelSubExprRule
    extends RelRule<CommonRelSubExprRule.Config> {
  //~ Constructors -----------------------------------------------------------

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

  @Deprecated // to be removed before 2.0
  protected CommonRelSubExprRule(RelOptRuleOperand operand) {
    this(Config.EMPTY.withOperandSupplier(b -> b.exactly(operand))
        .as(Config.class));
  }

  /** Rule configuration. */
  public interface Config extends RelRule.Config {
  }
}