src/main/java/net/hydromatic/optiq/impl/csv/CsvSmartTable.java

/*
// Licensed to Julian Hyde under one or more contributor license
// agreements. See the NOTICE file distributed with this work for
// additional information regarding copyright ownership.
//
// Julian Hyde 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 net.hydromatic.optiq.impl.csv;

import org.eigenbase.rel.RelNode;
import org.eigenbase.relopt.RelOptTable;
import org.eigenbase.relopt.RelOptUtil;
import org.eigenbase.reltype.RelDataType;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

/**
 * Refinement of {@link CsvTable} that plans itself.
 */
class CsvSmartTable extends CsvTable {

  /** Creates a CsvSmartTable. */
  CsvSmartTable(CsvSchema schema, String tableName, File file,
      RelDataType rowType, List<CsvFieldType> fieldTypes) {
    super(schema, tableName, file, rowType, fieldTypes);
  }

  /** Creates a table based on a CSV file, deducing its column types by reading
   * the first line of the file. */
  public static CsvSmartTable create(CsvSchema schema, File file,
      String tableName) {
    final List<CsvFieldType> fieldTypes = new ArrayList<CsvFieldType>();
    final RelDataType rowType =
        deduceRowType(schema.typeFactory, file, fieldTypes);
    return new CsvSmartTable(schema, tableName, file, rowType, fieldTypes);
  }

  public RelNode toRel(
      RelOptTable.ToRelContext context,
      RelOptTable relOptTable)
  {
    return new CsvTableScan(
        context.getCluster(),
        relOptTable,
        this,
        RelOptUtil.getFieldNameList(relOptTable.getRowType()));
  }
}

// End CsvSmartTable.java