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.csv;
  
  import org.apache.calcite.DataContext;
  import org.apache.calcite.adapter.file.CsvEnumerator;
  import org.apache.calcite.adapter.java.JavaTypeFactory;
  import org.apache.calcite.linq4j.AbstractEnumerable;
  import org.apache.calcite.linq4j.Enumerable;
  import org.apache.calcite.linq4j.Enumerator;
  import org.apache.calcite.linq4j.QueryProvider;
  import org.apache.calcite.linq4j.Queryable;
  import org.apache.calcite.linq4j.tree.Expression;
  import org.apache.calcite.plan.RelOptTable;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.type.RelProtoDataType;
  import org.apache.calcite.schema.QueryableTable;
  import org.apache.calcite.schema.SchemaPlus;
  import org.apache.calcite.schema.Schemas;
  import org.apache.calcite.schema.TranslatableTable;
  import org.apache.calcite.util.ImmutableIntList;
  import org.apache.calcite.util.Source;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.lang.reflect.Type;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  /**
   * Table based on a CSV file.
   */
  public class CsvTranslatableTable extends CsvTable
      implements QueryableTable, TranslatableTable {
    /** Creates a CsvTable. */
    CsvTranslatableTable(Source source, @Nullable RelProtoDataType protoRowType) {
      super(source, protoRowType);
    }
  
    @Override public String toString() {
      return "CsvTranslatableTable";
    }
  
    /** Returns an enumerable over a given projection of the fields. */
    @SuppressWarnings("unused") // called from generated code
    public Enumerable<Object> project(final DataContext root,
        final int[] fields) {
      final AtomicBoolean cancelFlag = DataContext.Variable.CANCEL_FLAG.get(root);
      return new AbstractEnumerable<Object>() {
        @Override public Enumerator<Object> enumerator() {
          JavaTypeFactory typeFactory = root.getTypeFactory();
          return new CsvEnumerator<>(
              source,
              cancelFlag,
              getFieldTypes(typeFactory),
              ImmutableIntList.of(fields));
        }
      };
    }
  
    @Override public Expression getExpression(SchemaPlus schema, String tableName,
        Class clazz) {
      return Schemas.tableExpression(schema, getElementType(), tableName, clazz);
    }
  
    @Override public Type getElementType() {
      return Object[].class;
    }
  
    @Override public <T> Queryable<T> asQueryable(QueryProvider queryProvider,
        SchemaPlus schema, String tableName) {
      throw new UnsupportedOperationException();
    }
  
    @Override public RelNode toRel(
        RelOptTable.ToRelContext context,
        RelOptTable relOptTable) {
      // Request all fields.
      final int fieldCount = relOptTable.getRowType().getFieldCount();
      final int[] fields = CsvEnumerator.identityList(fieldCount);
      return new CsvTableScan(context.getCluster(), relOptTable, this, fields);
    }
  }
  