Teng, Before you go down creating your own custom Spark system, do give some thought to what Holden and others are suggesting, viz. using implicit methods.
If you want real concrete examples, have a look at the Spark Cassandra Connector - Here you will see an example of "extending" SparkContext - https://github.com/datastax/spark-cassandra-connector/blob/master/doc/2_loading.md // validation is deferred, so it is not triggered during rdd creation val rdd = sc.cassandraTable[SomeType]("ks", "not_existing_table") val emptyRDD = rdd.toEmptyCassandraRDD val emptyRDD2 = sc.emptyCassandraTable[SomeType]("ks", "not_existing_table")) And here you will se an example of "extending" RDD - https://github.com/datastax/spark-cassandra-connector/blob/master/doc/5_saving.md case class WordCount(word: String, count: Long) val collection = sc.parallelize(Seq(WordCount("dog", 50), WordCount("cow", 60))) collection.saveToCassandra("test", "words", SomeColumns("word", "count")) Hope that helps… Jayesh From: Teng Long <longteng...@gmail.com> Date: Monday, December 5, 2016 at 3:04 PM To: Holden Karau <hol...@pigscanfly.ca>, <dev@spark.apache.org> Subject: Re: Can I add a new method to RDD class? Thank you for providing another answer, Holden. So I did what Tarun and Michal suggested, and it didn’t work out as I want to have a new transformation method in RDD class, and need to use that RDD’s spark context which is private. So I guess the only thing I can do now is to sbt publishLocal? On Dec 5, 2016, at 9:19 AM, Holden Karau <hol...@pigscanfly.ca<mailto:hol...@pigscanfly.ca>> wrote: Doing that requires publishing a custom version of Spark, you can edit the version number do do a publishLocal - but maintaining that change is going to be difficult. The other approaches suggested are probably better, but also does your method need to be defined on the RDD class? Could you instead make a helper object or class to expose whatever functionality you need? On Mon, Dec 5, 2016 at 6:06 PM long <longteng...@gmail.com<mailto:longteng...@gmail.com>> wrote: Thank you very much! But why can’t I just add new methods in to the source code of RDD? On Dec 5, 2016, at 3:15 AM, Michal Šenkýř [via Apache Spark Developers List] <[hidden email]<http://user/SendEmail.jtp?type=node&node=20107&i=0>> wrote: A simple Scala example of implicit classes: implicit class EnhancedString(str: String) { def prefix(prefix: String) = prefix + str } println("World".prefix("Hello ")) As Tarun said, you have to import it if it's not in the same class where you use it. Hope this makes it clearer, Michal Senkyr On 5.12.2016 07:43, Tarun Kumar wrote: Not sure if that's documented in terms of Spark but this is a fairly common pattern in scala known as "pimp my library" pattern, you can easily find many generic example of using this pattern. If you want I can quickly cook up a short conplete example with rdd(although there is nothing really more to my example in earlier mail) ? Thanks Tarun Kumar On Mon, 5 Dec 2016 at 7:15 AM, long <<a href="x-msg://22/user/SendEmail.jtp?type=node&node=20106&i=0" target="_top" rel="nofollow" link="external" class="">[hidden email]> wrote: So is there documentation of this I can refer to? On Dec 5, 2016, at 1:07 AM, Tarun Kumar [via Apache Spark Developers List] <[hidden email]<http://user/SendEmail.jtp?type=node&node=20104&i=0>> wrote: Hi Tenglong, In addition to trsell's reply, you can add any method to an rdd without making changes to spark code. This can be achieved by using implicit class in your own client code: implicit class extendRDD[T](rdd: RDD[T]){ def foo() } Then you basically nees to import this implicit class in scope where you want to use the new foo method. Thanks Tarun Kumar On Mon, 5 Dec 2016 at 6:59 AM, <<a href="<a href="x-msg://19/user/SendEmail.jtp?type=node&amp;node=20102&amp;i=0" class="">x-msg://19/user/SendEmail.jtp?type=node&node=20102&i=0" target="_top" rel="nofollow" link="external" class="">[hidden email]> wrote: How does your application fetch the spark dependency? Perhaps list your project dependencies and check it's using your dev build. On Mon, 5 Dec 2016, 08:47 tenglong, <<a href="<a href="x-msg://19/user/SendEmail.jtp?type=node&amp;node=20102&amp;i=1" class="">x-msg://19/user/SendEmail.jtp?type=node&node=20102&i=1" target="_top" rel="nofollow" link="external" class="">[hidden email]> wrote: Hi, Apparently, I've already tried adding a new method to RDD, for example, class RDD { def foo() // this is the one I added def map() def collect() } I can build Spark successfully, but I can't compile my application code which calls rdd.foo(), and the error message says value foo is not a member of org.apache.spark.rdd.RDD[String] So I am wondering if there is any mechanism prevents me from doing this or something I'm doing wrong? -- View this message in context: http://apache-spark-developers-list.1001551.n3.nabble.com/Can-I-add-a-new-method-to-RDD-class-tp20100.html Sent from the Apache Spark Developers List mailing list archive at Nabble.com<http://nabble.com/>. --------------------------------------------------------------------- To unsubscribe e-mail: <a href="<a href="x-msg://19/user/SendEmail.jtp?type=node&amp;node=20102&amp;i=2" class="">x-msg://19/user/SendEmail.jtp?type=node&node=20102&i=2" target="_top" rel="nofollow" link="external" class="">[hidden email] ________________________________ If you reply to this email, your message will be added to the discussion below: http://apache-spark-developers-list.1001551.n3.nabble.com/Can-I-add-a-new-method-to-RDD-class-tp20100p20102.html To unsubscribe from Can I add a new method to RDD class?, click here. 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