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.elasticsearch;
  
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelOptCost;
  import org.apache.calcite.plan.RelOptPlanner;
  import org.apache.calcite.plan.RelOptRule;
  import org.apache.calcite.plan.RelOptTable;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.TableScan;
  import org.apache.calcite.rel.metadata.RelMetadataQuery;
  import org.apache.calcite.rel.rules.CoreRules;
  import org.apache.calcite.rel.type.RelDataType;
  
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.List;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Relational expression representing a scan of an Elasticsearch type.
   *
   * <p> Additional operations might be applied,
   * using the "find" method.
   */
  public class ElasticsearchTableScan extends TableScan implements ElasticsearchRel {
    private final ElasticsearchTable elasticsearchTable;
    private final @Nullable RelDataType projectRowType;
  
    /**
     * Creates an ElasticsearchTableScan.
     *
     * @param cluster Cluster
     * @param traitSet Trait set
     * @param table Table
     * @param elasticsearchTable Elasticsearch table
     * @param projectRowType Fields and types to project; null to project raw row
     */
    ElasticsearchTableScan(RelOptCluster cluster, RelTraitSet traitSet,
         RelOptTable table, ElasticsearchTable elasticsearchTable,
         @Nullable RelDataType projectRowType) {
      super(cluster, traitSet, ImmutableList.of(), table);
      this.elasticsearchTable =
          requireNonNull(elasticsearchTable, "elasticsearchTable");
      this.projectRowType = projectRowType;
  
      assert getConvention() == ElasticsearchRel.CONVENTION;
    }
  
    @Override public RelNode copy(RelTraitSet traitSet, List<RelNode> inputs) {
      assert inputs.isEmpty();
      return this;
    }
  
    @Override public RelDataType deriveRowType() {
      return projectRowType != null ? projectRowType : super.deriveRowType();
    }
  
    @Override public @Nullable RelOptCost computeSelfCost(RelOptPlanner planner,
        RelMetadataQuery mq) {
      final float f = projectRowType == null ? 1f : (float) projectRowType.getFieldCount() / 100f;
      final RelOptCost cost = super.computeSelfCost(planner, mq);
      return requireNonNull(cost, "cost").multiplyBy(.1 * f);
    }
  
    @Override public void register(RelOptPlanner planner) {
      planner.addRule(ElasticsearchToEnumerableConverterRule.INSTANCE);
      for (RelOptRule rule : ElasticsearchRules.RULES) {
        planner.addRule(rule);
      }
  
      // remove this rule otherwise elastic can't correctly interpret approx_count_distinct()
      // it is converted to cardinality aggregation in Elastic
      planner.removeRule(CoreRules.AGGREGATE_EXPAND_DISTINCT_AGGREGATES);
    }
  
    @Override public void implement(Implementor implementor) {
      implementor.elasticsearchTable = elasticsearchTable;
      implementor.table = table;
    }
  }
  