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.adapter.geode.rel;
  
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelOptCost;
  import org.apache.calcite.plan.RelOptPlanner;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.RelCollation;
  import org.apache.calcite.rel.RelFieldCollation;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.Sort;
  import org.apache.calcite.rel.metadata.RelMetadataQuery;
  import org.apache.calcite.rex.RexLiteral;
  import org.apache.calcite.rex.RexNode;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Implementation of
   * {@link Sort}
   * relational expression in Geode.
   */
  public class GeodeSort extends Sort implements GeodeRel {
  
    public static final String ASC = "ASC";
    public static final String DESC = "DESC";
  
    /** Creates a GeodeSort. */
    GeodeSort(RelOptCluster cluster, RelTraitSet traitSet,
        RelNode input, RelCollation collation, @Nullable RexNode fetch) {
      super(cluster, traitSet, input, collation, null, fetch);
  
      assert getConvention() == GeodeRel.CONVENTION;
      assert getConvention() == input.getConvention();
    }
  
    @Override public @Nullable RelOptCost computeSelfCost(RelOptPlanner planner,
        RelMetadataQuery mq) {
      final RelOptCost cost = requireNonNull(super.computeSelfCost(planner, mq));
      if (fetch != null) {
        return cost.multiplyBy(0.05);
      } else {
        return cost.multiplyBy(0.9);
      }
    }
  
    @Override public Sort copy(RelTraitSet traitSet, RelNode input,
        RelCollation newCollation, RexNode offset, RexNode fetch) {
      return new GeodeSort(getCluster(), traitSet, input, collation, fetch);
    }
  
    @Override public void implement(GeodeImplementContext geodeImplementContext) {
      geodeImplementContext.visitChild(getInput());
  
      List<RelFieldCollation> sortCollations = collation.getFieldCollations();
  
      if (!sortCollations.isEmpty()) {
  
        List<String> orderByFields = new ArrayList<>();
  
        for (RelFieldCollation fieldCollation : sortCollations) {
          final String name = fieldName(fieldCollation.getFieldIndex());
          orderByFields.add(name + " " + direction(fieldCollation.getDirection()));
        }
        geodeImplementContext.addOrderByFields(orderByFields);
      }
  
      if (fetch != null) {
        geodeImplementContext.setLimit(RexLiteral.numberValue(fetch).longValue());
      }
    }
  
    private String fieldName(int index) {
      return getRowType().getFieldList().get(index).getName();
    }
  
    private static String direction(RelFieldCollation.Direction relDirection) {
      if (relDirection == RelFieldCollation.Direction.DESCENDING) {
        return DESC;
      }
      return ASC;
    }
  }
  