Just to add to my previous question, I see this example in Hive
documentation for the "reflect" UDF. What object or string is the "isEmpty"
method working on in the example below? What I am trying to do with
hashCode() is something similar.
SELECT reflect("java.lang.String", "valueOf", 1),
reflect("java.lang.String", "isEmpty"),
reflect("java.lang.Math", "max", 2, 3),
reflect("java.lang.Math", "min", 2, 3),
reflect("java.lang.Math", "round", 2.5),
reflect("java.lang.Math", "exp", 1.0),
reflect("java.lang.Math", "floor", 1.9)
FROM src LIMIT 1;
1 true 3 2 3 2.7182818284590455 1.0
Thanks,
Andy
On Thu, Apr 3, 2014 at 11:22 AM, Andy Srine <andy.sr...@gmail.com> wrote:
> Thanks Szehon and Peyman, I want to call hashCode() on the UUID object.
> This object is stored in the table as a string, but I can convert it to
> UUID. Thats not the problem.
>
> Basically the question is, how do we call this reflect UDF on methods that
> takes no arguments? How do I do the following using the reflect UDF?
>
> (fromString(uid_str)).hashCode()
>
> Thanks,
> Andy
>
>
>
>
> On Thu, Apr 3, 2014 at 6:18 AM, Peyman Mohajerian <mohaj...@gmail.com>wrote:
>
>> Maybe your intention is the following:
>> reflect("java.util.UUID", "randomUUID")
>>
>>
>> On Thu, Apr 3, 2014 at 2:33 AM, Szehon Ho <sze...@cloudera.com> wrote:
>>
>>> Hi, according to the description of the reflect UDF, you are trying to
>>> call java.util.UUID.hashcode(uidString), which doesnt seem to be an
>>> existing method on either java 6/7.
>>>
>>> http://docs.oracle.com/javase/7/docs/api/java/util/UUID.html#hashCode()
>>>
>>> Thanks
>>> Szehon
>>>
>>>
>>>
>>>
>>> On Wed, Apr 2, 2014 at 2:13 PM, Andy Srine <andy.sr...@gmail.com> wrote:
>>>
>>>> Hi guys,
>>>>
>>>>
>>>> I am trying to use the reflect UDF for an UUID method and am getting an
>>>> exception. I believe this function should be available in java 1.6.0_31 the
>>>> system is running.
>>>>
>>>>
>>>> select reflect("java.util.UUID", "hashCode", uid_str) my_uid,
>>>>
>>>> ...
>>>>
>>>>
>>>> My suspicion is, this is because the hive column I am calling this on
>>>> is a string and not an UUID. So I nested the reflects as shown below to go
>>>> from a string to an UUID first and then to "hashCode" it.
>>>>
>>>>
>>>> reflect("java.util.UUID", "hashCode", reflect("java.util.UUID",
>>>> "fromString", uid_str)) my_uid,
>>>>
>>>>
>>>> In either case, I always get the exception below though the row of data
>>>> it prints has no null for the uid_str column. Any ideas?
>>>>
>>>>
>>>> at
>>>> org.apache.hadoop.hive.ql.exec.MapOperator.process(MapOperator.java:565)
>>>>
>>>> at org.apache.hadoop.hive.ql.exec.ExecMapper.map(ExecMapper.java:143)
>>>>
>>>> ... 8 more
>>>>
>>>> Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: UDFReflect
>>>> getMethod
>>>>
>>>> at
>>>> org.apache.hadoop.hive.ql.udf.generic.GenericUDFReflect.evaluate(GenericUDFReflect.java:164)
>>>>
>>>> at
>>>> org.apache.hadoop.hive.ql.exec.ExprNodeGenericFuncEvaluator.evaluate(ExprNodeGenericFuncEvaluator.java:163)
>>>>
>>>> at
>>>> org.apache.hadoop.hive.ql.exec.KeyWrapperFactory$ListKeyWrapper.getNewKey(KeyWrapperFactory.java:113)
>>>>
>>>> at
>>>> org.apache.hadoop.hive.ql.exec.GroupByOperator.processOp(GroupByOperator.java:794)
>>>>
>>>> at org.apache.hadoop.hive.ql.exec.Operator.process(Operator.java:474)
>>>>
>>>> at org.apache.hadoop.hive.ql.exec.Operator.forward(Operator.java:800)
>>>>
>>>> at
>>>> org.apache.hadoop.hive.ql.exec.SelectOperator.processOp(SelectOperator.java:84)
>>>>
>>>> at org.apache.hadoop.hive.ql.exec.Operator.process(Operator.java:474)
>>>>
>>>> at org.apache.hadoop.hive.ql.exec.Operator.forward(Operator.java:800)
>>>>
>>>> at
>>>> org.apache.hadoop.hive.ql.exec.TableScanOperator.processOp(TableScanOperator.java:83)
>>>>
>>>> at org.apache.hadoop.hive.ql.exec.Operator.process(Operator.java:474)
>>>>
>>>> at org.apache.hadoop.hive.ql.exec.Operator.forward(Operator.java:800)
>>>>
>>>> at
>>>> org.apache.hadoop.hive.ql.exec.MapOperator.process(MapOperator.java:548)
>>>>
>>>> ... 9 more
>>>>
>>>> Caused by: java.lang.NoSuchMethodException:
>>>> java.util.UUID.hashCode(null)
>>>>
>>>> at java.lang.Class.getMethod(Class.java:1605)
>>>>
>>>> at
>>>> org.apache.hadoop.hive.ql.udf.generic.GenericUDFReflect.evaluate(GenericUDFReflect.java:160)
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Andy
>>>>
>>>>
>>>>
>>>
>>
>
>
> --
> Thanks,
> Andy
>
>
--
Thanks,
Andy
