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From "Paul Yang (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-471) A UDF for simple reflection
Date Sat, 06 Feb 2010 02:27:27 GMT

    [ https://issues.apache.org/jira/browse/HIVE-471?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12830431#action_12830431
] 

Paul Yang commented on HIVE-471:
--------------------------------

Question about the patch - for className and methodName in evaluate(), it looks like we are
making a copy of the object and the object inspector so we can use ObjectInspectorUtils.compare().
But since we know that the class name and method name arguments are inspectable by a  StringObjectInspector,
can't we save the the name of the class/method as a java string and check for equality with
'=='? 

> A UDF for simple reflection
> ---------------------------
>
>                 Key: HIVE-471
>                 URL: https://issues.apache.org/jira/browse/HIVE-471
>             Project: Hadoop Hive
>          Issue Type: New Feature
>          Components: Query Processor
>    Affects Versions: 0.6.0
>            Reporter: Edward Capriolo
>            Assignee: Edward Capriolo
>            Priority: Minor
>         Attachments: hive-471-gen.diff, HIVE-471.1.patch, hive-471.diff
>
>
> There are many methods in java that are static and have no arguments or can be invoked
with one simple parameter. More complicated functions will require a UDF but one generic one
can work as a poor-mans UDF.
> {noformat}
> SELECT reflect("java.lang.String", "valueOf", 1), reflect("java.lang.String", "isEmpty")
> FROM src LIMIT 1;
> {noformat}

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