Sounds like the wikidoc needs some work. I'm open to suggestions. If
Sanjay's simple UDF helps, I could put it in the wiki along with any advice
you think would help.
Does anyone else have use cases to contribute?
-- Lefty
On Mon, Aug 5, 2013 at 2:45 PM, Sanjay Subramanian <
sanjay.subraman...@wizecommerce.com> wrote:
> Hi Ritesh
>
> To help u get started , I am writing a simple HelloWorld-ish UDF that
> might help…If it doesn't please ask for more clarifications...
>
> Good Luck
> Thanks
>
> sanjay
>
>
> ********************************************************************************
> *ToUpperCase.java*
>
> *package* com.sanjaysubramanian.utils.hive.udf;
>
> *import* org.apache.hadoop.hive.ql.exec.UDF;
>
>
> *public* *final* *class* ToUpperCase *extends* UDF{
>
> *protected* *final* Log logger = LogFactory.*getLog*(toUpperCase.*
> class*);
>
>
> *public* *String* evaluate(*final* String inputString) {
>
> if (inputString != null){
>
> *return* inputString.toUpper;
>
> }
>
> else {
>
> *return* inputString;
>
> }
>
> }
>
> }
>
> ********************************************************************************
>
> *Usage in a Hive script*
> *
> *
> hive -e "
>
> create temporary function toupper as
> 'com.sanjaysubramanian.utils.hive.udf.ToUpperCase';
> SELECT
> first_name,
> toupper(first_name)
> FROM
> company_names
> "
>
>
> ***********************************************************************************
>
> From: Ritesh Agrawal <ragra...@netflix.com>
> Reply-To: "user@hive.apache.org" <user@hive.apache.org>
> Date: Monday, August 5, 2013 9:41 AM
> To: "user@hive.apache.org" <user@hive.apache.org>
> Subject: Re: Hive UDAF extending UDAF class: iterate or evaluate method
>
> Hi Lefty,
>
> I used the wiki you sent to write my first version of UDAF. However, I
> found it to be utterly complex, especially for storing partial results as I
> am not very familiar with hive API. Then I found another example of UDAF in
> the hadoop the definitive guide book and it had much simpler code but using
> different method. Instead of using iterate it was using evaluate method and
> so I am getting confused.
>
> Ritesh
>
>
> On Sun, Aug 4, 2013 at 2:18 PM, Lefty Leverenz <leftylever...@gmail.com>wrote:
>
>> You might find this wikidoc useful:
>> GenericUDAFCaseStudy<https://cwiki.apache.org/confluence/display/Hive/GenericUDAFCaseStudy>.
>>
>>
>> The O'Reilly book "Programming Hive" also has a section called
>> "User-Defined Aggregate Functions" in chapter 13 (Functions), pages 172 to
>> 176.
>>
>> -- Lefty
>>
>>
>> On Sun, Aug 4, 2013 at 7:12 AM, Ritesh Agrawal <ragra...@netflix.com>wrote:
>>
>>> Hi all,
>>>
>>> I am trying to write a UDAF function. I found an example that shows
>>> how to implement a UDAF in "Hadoop The Definitive Guide" book. However I am
>>> little confused. In the book, the author extends UDAF class and implements
>>> init, iterate, terminatePartial, merge and terminate function. However
>>> looking at the hive docs (
>>> http://hive.apache.org/docs/r0.11.0/api/org/apache/hadoop/hive/ql/exec/UDAF.html),
>>> it seems I need to implement init, aggregate, evaluatePartial,
>>> aggregatePartial and evaluate function. Please let me know what are the
>>> write functions to implement.
>>>
>>> Ritesh
>>>
>>
>>
>>
>> --
>> Lefty
>>
>
>
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--
Lefty
