Support for writing CSV with a single function call

Author: HyukjinKwon

sql/core/src/main/scala/org/apache/spark/sql/DataFrameWriter.scala

@@ -464,6 +464,12 @@ final class DataFrameWriter private[sql](df: DataFrame) {
    *   format("parquet").save(path)
    * }}}
    *
+   * You can set the following JSON-specific options for writing JSON files:
+   * <li>`compression` or `codec` (default `null`): compression codec to use when saving to file.
+   * This should be the fully qualified name of a class implementing
+   * [[org.apache.hadoop.io.compress.CompressionCodec]] or one of the known case-insensitive
+   * shorten names(`bzip2`, `gzip`, `lz4`, and `snappy`). </li>
+   *
    * @since 1.4.0
    */
   def parquet(path: String): Unit = format("parquet").save(path)
@@ -492,10 +498,33 @@ final class DataFrameWriter private[sql](df: DataFrame) {
    *   df.write().text("/path/to/output")
    * }}}
    *
+   * You can set the following options for writing text files:
+   * <li>`compression` or `codec` (default `null`): compression codec to use when saving to file.
+   * This should be the fully qualified name of a class implementing
+   * [[org.apache.hadoop.io.compress.CompressionCodec]] or one of the known case-insensitive
+   * shorten names(`bzip2`, `gzip`, `lz4`, and `snappy`). </li>
+   *
    * @since 1.6.0
    */
   def text(path: String): Unit = format("text").save(path)
 
+  /**
+   * Saves the content of the [[DataFrame]] in CSV format at the specified path.
+   * This is equivalent to:
+   * {{{
+   *   format("csv").save(path)
+   * }}}
+   *
+   * You can set the following CSV-specific options for writing CSV files:
+   * <li>`compression` or `codec` (default `null`): compression codec to use when saving to file.
+   * This should be the fully qualified name of a class implementing
+   * [[org.apache.hadoop.io.compress.CompressionCodec]] or one of the known case-insensitive
+   * shorten names(`bzip2`, `gzip`, `lz4`, and `snappy`). </li>
+   *
+   * @since 2.0.0
+   */
+  def csv(path: String): Unit = format("csv").save(path)
+
   ///////////////////////////////////////////////////////////////////////////////////////
   // Builder pattern config options
   ///////////////////////////////////////////////////////////////////////////////////////

sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVSuite.scala

@@ -268,9 +268,8 @@ class CSVSuite extends QueryTest with SharedSQLContext with SQLTestUtils {
         .load(testFile(carsFile))
 
       cars.coalesce(1).write
-        .format("csv")
         .option("header", "true")
-        .save(csvDir)
+        .csv(csvDir)
 
       val carsCopy = sqlContext.read
         .format("csv")