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]
> <ml-node+s1001551n20106...@n3.nabble.com> 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 <[hidden email]
>> <x-msg://22/user/SendEmail.jtp?type=node&node=20106&i=0>> 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="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="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?
>>>
>>>
>>>
>>>
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