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.enumerable;
  
  import org.apache.calcite.plan.RelOptRuleCall;
  import org.apache.calcite.plan.RelRule;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.Sort;
  import org.apache.calcite.rel.logical.LogicalSort;
  
  import org.immutables.value.Value;
  
  /**
   * Rule to convert an {@link LogicalSort} with ({@link LogicalSort#fetch}
   * or {@link LogicalSort#offset}) and {@link LogicalSort#collation}(Order By)
   * into an {@link EnumerableLimitSort}.
   */
  @Value.Enclosing
  public class EnumerableLimitSortRule extends RelRule<EnumerableLimitSortRule.Config> {
  
    /**
     * Creates a EnumerableLimitSortRule.
     */
    public EnumerableLimitSortRule(Config config) {
      super(config);
    }
  
    @Override public void onMatch(RelOptRuleCall call) {
      final Sort sort = call.rel(0);
      RelNode input = sort.getInput();
      final Sort o =
          EnumerableLimitSort.create(
              convert(call.getPlanner(), input,
                  input.getTraitSet().replace(EnumerableConvention.INSTANCE)),
              sort.getCollation(), sort.offset, sort.fetch);
  
      call.transformTo(o);
    }
  
    /** Rule configuration. */
    @Value.Immutable
    public interface Config extends RelRule.Config {
      Config DEFAULT =
          ImmutableEnumerableLimitSortRule.Config.of()
              .withOperandSupplier(b0 ->
                  b0.operand(LogicalSort.class)
                      .predicate(sort -> (sort.fetch != null || sort.offset != null)
                          && !sort.collation.getFieldCollations().isEmpty())
                      .anyInputs());
  
      @Override default EnumerableLimitSortRule toRule() {
        return new EnumerableLimitSortRule(this);
      }
    }
  }
  