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.logical;
  
  import org.apache.calcite.plan.Convention;
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.RelInput;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.RelShuttle;
  import org.apache.calcite.rel.core.Union;
  import org.apache.calcite.rel.hint.RelHint;
  
  import java.util.Collections;
  import java.util.List;
  
  /**
   * Sub-class of {@link org.apache.calcite.rel.core.Union}
   * not targeted at any particular engine or calling convention.
   */
  public final class LogicalUnion extends Union {
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Creates a LogicalUnion.
     *
     * <p>Use {@link #create} unless you know what you're doing.
     */
    public LogicalUnion(RelOptCluster cluster,
        RelTraitSet traitSet,
        List<RelHint> hints,
        List<RelNode> inputs,
        boolean all) {
      super(cluster, traitSet, hints, inputs, all);
    }
  
    /**
     * Creates a LogicalUnion.
     *
     * <p>Use {@link #create} unless you know what you're doing.
     */
    public LogicalUnion(RelOptCluster cluster,
        RelTraitSet traitSet,
        List<RelNode> inputs,
        boolean all) {
      this(cluster, traitSet, Collections.emptyList(), inputs, all);
    }
  
    @Deprecated // to be removed before 2.0
    public LogicalUnion(RelOptCluster cluster, List<RelNode> inputs,
        boolean all) {
      this(cluster, cluster.traitSetOf(Convention.NONE), inputs, all);
    }
  
    /**
     * Creates a LogicalUnion by parsing serialized output.
     */
    public LogicalUnion(RelInput input) {
      super(input);
    }
  
    /** Creates a LogicalUnion. */
    public static LogicalUnion create(List<RelNode> inputs, boolean all) {
      final RelOptCluster cluster = inputs.get(0).getCluster();
      final RelTraitSet traitSet = cluster.traitSetOf(Convention.NONE);
      return new LogicalUnion(cluster, traitSet, inputs, all);
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public LogicalUnion copy(
        RelTraitSet traitSet, List<RelNode> inputs, boolean all) {
      assert traitSet.containsIfApplicable(Convention.NONE);
      return new LogicalUnion(getCluster(), traitSet, hints, inputs, all);
    }
  
    @Override public RelNode accept(RelShuttle shuttle) {
      return shuttle.visit(this);
    }
  
    @Override public RelNode withHints(List<RelHint> hintList) {
      return new LogicalUnion(getCluster(), traitSet, hintList, inputs, all);
    }
  }
  