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 org.apache.beam.sdk.extensions.sql.impl.rel.BeamLogicalConvention;
  import org.apache.beam.sdk.extensions.sql.impl.rel.BeamUnionRel;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.Convention;
  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.convert.ConverterRule;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.core.Union;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.logical.LogicalUnion;
  
  /**
   * A {@code ConverterRule} to replace {@link
   * org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.core.Union} with {@link
   * BeamUnionRule}.
   */
  public class BeamUnionRule extends ConverterRule {
    public static final BeamUnionRule INSTANCE = new BeamUnionRule();
  
    private BeamUnionRule() {
      super(LogicalUnion.class, Convention.NONE, BeamLogicalConvention.INSTANCE, "BeamUnionRule");
    }
  
    @Override
    public RelNode convert(RelNode rel) {
      Union union = (Union) rel;
  
      return new BeamUnionRel(
          union.getCluster(),
          union.getTraitSet().replace(BeamLogicalConvention.INSTANCE),
          convertList(union.getInputs(), BeamLogicalConvention.INSTANCE),
          union.all);
    }
  }
  