and the PR: https://github.com/apache/spark/pull/5564
Thank you ! Olivier. Le ven. 17 avr. 2015 à 23:00, Reynold Xin <r...@databricks.com> a écrit : > No there isn't a convention. Although if you want to show java 8, you > should also show java 6/7 syntax since there are still more 7 users than 8. > > > On Fri, Apr 17, 2015 at 3:36 PM, Olivier Girardot < > o.girar...@lateral-thoughts.com> wrote: > >> Is there any convention *not* to show java 8 versions in the >> documentation ? >> >> Le ven. 17 avr. 2015 à 21:39, Reynold Xin <r...@databricks.com> a écrit : >> >>> Please do! Thanks. >>> >>> >>> On Fri, Apr 17, 2015 at 2:36 PM, Olivier Girardot < >>> o.girar...@lateral-thoughts.com> wrote: >>> >>>> Ok, do you want me to open a pull request to fix the dedicated >>>> documentation ? >>>> >>>> Le ven. 17 avr. 2015 à 18:14, Reynold Xin <r...@databricks.com> a >>>> écrit : >>>> >>>>> I think in 1.3 and above, you'd need to do >>>>> >>>>> .sql(...).javaRDD().map(..) >>>>> >>>>> On Fri, Apr 17, 2015 at 9:22 AM, Olivier Girardot < >>>>> o.girar...@lateral-thoughts.com> wrote: >>>>> >>>>>> Yes thanks ! >>>>>> >>>>>> Le ven. 17 avr. 2015 à 16:20, Ted Yu <yuzhih...@gmail.com> a écrit : >>>>>> >>>>>> > The image didn't go through. >>>>>> > >>>>>> > I think you were referring to: >>>>>> > override def map[R: ClassTag](f: Row => R): RDD[R] = rdd.map(f) >>>>>> > >>>>>> > Cheers >>>>>> > >>>>>> > On Fri, Apr 17, 2015 at 6:07 AM, Olivier Girardot < >>>>>> > o.girar...@lateral-thoughts.com> wrote: >>>>>> > >>>>>> > > Hi everyone, >>>>>> > > I had an issue trying to use Spark SQL from Java (8 or 7), I >>>>>> tried to >>>>>> > > reproduce it in a small test case close to the actual >>>>>> documentation >>>>>> > > < >>>>>> > >>>>>> https://spark.apache.org/docs/latest/sql-programming-guide.html#inferring-the-schema-using-reflection >>>>>> > >, >>>>>> > > so sorry for the long mail, but this is "Java" : >>>>>> > > >>>>>> > > import org.apache.spark.api.java.JavaRDD; >>>>>> > > import org.apache.spark.api.java.JavaSparkContext; >>>>>> > > import org.apache.spark.sql.DataFrame; >>>>>> > > import org.apache.spark.sql.SQLContext; >>>>>> > > >>>>>> > > import java.io.Serializable; >>>>>> > > import java.util.ArrayList; >>>>>> > > import java.util.Arrays; >>>>>> > > import java.util.List; >>>>>> > > >>>>>> > > class Movie implements Serializable { >>>>>> > > private int id; >>>>>> > > private String name; >>>>>> > > >>>>>> > > public Movie(int id, String name) { >>>>>> > > this.id = id; >>>>>> > > this.name = name; >>>>>> > > } >>>>>> > > >>>>>> > > public int getId() { >>>>>> > > return id; >>>>>> > > } >>>>>> > > >>>>>> > > public void setId(int id) { >>>>>> > > this.id = id; >>>>>> > > } >>>>>> > > >>>>>> > > public String getName() { >>>>>> > > return name; >>>>>> > > } >>>>>> > > >>>>>> > > public void setName(String name) { >>>>>> > > this.name = name; >>>>>> > > } >>>>>> > > } >>>>>> > > >>>>>> > > public class SparkSQLTest { >>>>>> > > public static void main(String[] args) { >>>>>> > > SparkConf conf = new SparkConf(); >>>>>> > > conf.setAppName("My Application"); >>>>>> > > conf.setMaster("local"); >>>>>> > > JavaSparkContext sc = new JavaSparkContext(conf); >>>>>> > > >>>>>> > > ArrayList<Movie> movieArrayList = new ArrayList<Movie>(); >>>>>> > > movieArrayList.add(new Movie(1, "Indiana Jones")); >>>>>> > > >>>>>> > > JavaRDD<Movie> movies = sc.parallelize(movieArrayList); >>>>>> > > >>>>>> > > SQLContext sqlContext = new SQLContext(sc); >>>>>> > > DataFrame frame = sqlContext.applySchema(movies, >>>>>> Movie.class); >>>>>> > > frame.registerTempTable("movies"); >>>>>> > > >>>>>> > > sqlContext.sql("select name from movies") >>>>>> > > >>>>>> > > * .map(row -> row.getString(0)) // this is what i >>>>>> would >>>>>> > expect to work * .collect(); >>>>>> > > } >>>>>> > > } >>>>>> > > >>>>>> > > >>>>>> > > But this does not compile, here's the compilation error : >>>>>> > > >>>>>> > > [ERROR] >>>>>> > > >>>>>> > >>>>>> /Users/ogirardot/Documents/spark/java-project/src/main/java/org/apache/spark/MainSQL.java:[37,47] >>>>>> > > method map in class org.apache.spark.sql.DataFrame cannot be >>>>>> applied to >>>>>> > > given types; >>>>>> > > [ERROR] *required: >>>>>> > > >>>>>> scala.Function1<org.apache.spark.sql.Row,R>,scala.reflect.ClassTag<R> * >>>>>> > > [ERROR]* found: (row)->"Na[...]ng(0) * >>>>>> > > [ERROR] *reason: cannot infer type-variable(s) R * >>>>>> > > [ERROR] *(actual and formal argument lists differ in length) * >>>>>> > > [ERROR] >>>>>> > > >>>>>> > >>>>>> /Users/ogirardot/Documents/spark/java-project/src/main/java/org/apache/spark/SampleSHit.java:[56,17] >>>>>> > > method map in class org.apache.spark.sql.DataFrame cannot be >>>>>> applied to >>>>>> > > given types; >>>>>> > > [ERROR] required: >>>>>> > > >>>>>> scala.Function1<org.apache.spark.sql.Row,R>,scala.reflect.ClassTag<R> >>>>>> > > [ERROR] found: (row)->row[...]ng(0) >>>>>> > > [ERROR] reason: cannot infer type-variable(s) R >>>>>> > > [ERROR] (actual and formal argument lists differ in length) >>>>>> > > [ERROR] -> [Help 1] >>>>>> > > >>>>>> > > Because in the DataFrame the *map *method is defined as : >>>>>> > > >>>>>> > > [image: Images intégrées 1] >>>>>> > > >>>>>> > > And once this is translated to bytecode the actual Java signature >>>>>> uses a >>>>>> > > Function1 and adds a ClassTag parameter. >>>>>> > > I can try to go around this and use the scala.reflect.ClassTag$ >>>>>> like >>>>>> > that : >>>>>> > > >>>>>> > > ClassTag$.MODULE$.apply(String.class) >>>>>> > > >>>>>> > > To get the second ClassTag parameter right, but then >>>>>> instantiating a >>>>>> > java.util.Function or using the Java 8 lambdas fail to work, and if >>>>>> I try >>>>>> > to instantiate a proper scala Function1... well this is a world of >>>>>> pain. >>>>>> > > >>>>>> > > This is a regression introduced by the 1.3.x DataFrame because >>>>>> > JavaSchemaRDD used to be JavaRDDLike but DataFrame's are not (and >>>>>> are not >>>>>> > callable with JFunctions), I can open a Jira if you want ? >>>>>> > > >>>>>> > > Regards, >>>>>> > > >>>>>> > > -- >>>>>> > > *Olivier Girardot* | Associé >>>>>> > > o.girar...@lateral-thoughts.com >>>>>> > > +33 6 24 09 17 94 >>>>>> > > >>>>>> > >>>>>> >>>>> >>>>> >>> >
