org.apache.spark.sql.DatasetHolder.scala Maven / Gradle / Ivy

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/*
* 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,
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* See the License for the specific language governing permissions and
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package org.apache.spark.sql

/**
 * A container for a [[Dataset]], used for implicit conversions in Scala.
 *
 * To use this, import implicit conversions in SQL:
 * {{{
 *   import sqlContext.implicits._
 * }}}
 *
 * @since 1.6.0
 */
case class DatasetHolder[T] private[sql](private val ds: Dataset[T]) {

  // This is declared with parentheses to prevent the Scala compiler from treating
  // `rdd.toDS("1")` as invoking this toDS and then apply on the returned Dataset.
  def toDS(): Dataset[T] = ds

  // This is declared with parentheses to prevent the Scala compiler from treating
  // `rdd.toDF("1")` as invoking this toDF and then apply on the returned DataFrame.
  def toDF(): DataFrame = ds.toDF()

  def toDF(colNames: String*): DataFrame = ds.toDF(colNames : _*)
}