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.RelCollation;
  import org.apache.calcite.rel.RelCollationTraitDef;
  import org.apache.calcite.rel.RelInput;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.RelShuttle;
  import org.apache.calcite.rel.core.Sort;
  import org.apache.calcite.rel.hint.RelHint;
  import org.apache.calcite.rex.RexNode;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.Collections;
  import java.util.List;
  
  /**
   * Sub-class of {@link org.apache.calcite.rel.core.Sort} not
   * targeted at any particular engine or calling convention.
   */
  public final class LogicalSort extends Sort {
    private LogicalSort(RelOptCluster cluster, RelTraitSet traitSet,
        RelNode input, RelCollation collation, @Nullable RexNode offset, @Nullable RexNode fetch) {
      this(cluster, traitSet, Collections.emptyList(), input, collation, offset, fetch);
    }
  
    private LogicalSort(RelOptCluster cluster, RelTraitSet traitSet, List<RelHint> hints,
        RelNode input, RelCollation collation, @Nullable RexNode offset, @Nullable RexNode fetch) {
      super(cluster, traitSet, hints, input, collation, offset, fetch);
      assert traitSet.containsIfApplicable(Convention.NONE);
    }
  
    /**
     * Creates a LogicalSort by parsing serialized output.
     */
    public LogicalSort(RelInput input) {
      super(input);
    }
  
    /**
     * Creates a LogicalSort.
     *
     * @param input     Input relational expression
     * @param collation array of sort specifications
     * @param offset    Expression for number of rows to discard before returning
     *                  first row
     * @param fetch     Expression for number of rows to fetch
     */
    public static LogicalSort create(RelNode input, RelCollation collation,
        @Nullable RexNode offset, @Nullable RexNode fetch) {
      RelOptCluster cluster = input.getCluster();
      collation = RelCollationTraitDef.INSTANCE.canonize(collation);
      RelTraitSet traitSet =
          input.getTraitSet().replace(Convention.NONE).replace(collation);
      return new LogicalSort(cluster, traitSet, input, collation, offset, fetch);
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public Sort copy(RelTraitSet traitSet, RelNode newInput,
        RelCollation newCollation, @Nullable RexNode offset, @Nullable RexNode fetch) {
      return new LogicalSort(getCluster(), traitSet, hints, newInput,
          newCollation, offset, fetch);
    }
  
    @Override public RelNode accept(RelShuttle shuttle) {
      return shuttle.visit(this);
    }
  
    @Override public RelNode withHints(List<RelHint> hintList) {
      return new LogicalSort(getCluster(), traitSet, hintList,
          input, collation, offset, fetch);
    }
  }
  