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.beam.sdk.extensions.sql.impl.rule;
  
  import java.util.List;
  import java.util.Map;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelHintsPropagator;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelOptPlanner;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelOptRule;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelOptRuleCall;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelOptRuleOperand;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.RelNode;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.metadata.RelMetadataQuery;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.tools.RelBuilder;
  
  /**
   * This is a class to catch the built join and check if it is a legal join before passing it to the
   * actual RelOptRuleCall.
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class JoinRelOptRuleCall extends RelOptRuleCall {
    private final RelOptRuleCall originalCall;
    private final JoinChecker checker;
  
    JoinRelOptRuleCall(RelOptRuleCall originalCall, JoinChecker checker) {
      super(originalCall.getPlanner(), originalCall.getOperand0(), originalCall.rels, null, null);
      this.originalCall = originalCall;
      this.checker = checker;
    }
  
    // This is the only method that is different than originalCall. Everything else is delegated to
    // originalCall.
    @Override
    public void transformTo(RelNode rel, Map<RelNode, RelNode> equiv) {
      if (checker.check(rel)) {
        originalCall.transformTo(rel, equiv);
      }
    }
  
    @Override
    public void transformTo(
        RelNode relNode, Map<RelNode, RelNode> map, RelHintsPropagator relHintsPropagator) {
      if (checker.check(relNode)) {
        originalCall.transformTo(relNode, map, relHintsPropagator);
      }
    }
  
    /** This is a function gets the output relation and checks if it is a legal relational node. */
    public interface JoinChecker {
      boolean check(RelNode rel);
    }
  
    // Methods that are delegated to originalCall.
  
    @Override
    public RelOptRuleOperand getOperand0() {
      return originalCall.getOperand0();
    }
  
    @Override
    public RelOptRule getRule() {
      return originalCall.getRule();
    }
  
    @Override
    public List<RelNode> getRelList() {
      return originalCall.getRelList();
    }
  
    @Override
    @SuppressWarnings("TypeParameterUnusedInFormals")
    public <T extends RelNode> T rel(int ordinal) {
      return originalCall.rel(ordinal);
    }
  
    @Override
    public List<RelNode> getChildRels(RelNode rel) {
      return originalCall.getChildRels(rel);
    }
  
    @Override
    public RelOptPlanner getPlanner() {
      return originalCall.getPlanner();
    }
  
    @Override
    public RelMetadataQuery getMetadataQuery() {
      return originalCall.getMetadataQuery();
    }
  
    @Override
    public List<RelNode> getParents() {
      return originalCall.getParents();
    }
  
    @Override
    public RelBuilder builder() {
      return originalCall.builder();
    }
  }
  