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https://issues.apache.org/jira/browse/PIG-1303?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12860297#action_12860297
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hc busy commented on PIG-1303:
------------------------------
But the problem is that inside the EvalFunc constructor, in case of Algebraic
classes, it constructs each of Initial, Intermediate and final which are
EvalFunc's that, in my case, require a parameter to operate correctly.
If I declare the helper class that represent the initial/intermediate/final
{code}
public class HelperClass extends EvalFunc<Tuple> {
public HelperClass() {
super();
}
public Tuple exec(Tuple input) throws IOException {
return extreme(fieldIndex, sign, input, reporter);
}
}
{code}
where the fieldIndex and sign come from the surrounding class (note the class
is not static) then the code crashes. It's not able to construct the
HelperClass with this error
{quote}
could not instantiate
'org.apache.pig.piggybank.evaluation.ExtremalTupleByNthField$HelperClass' with
arguments 'null'
java.lang.RuntimeException: could not instantiate
'org.apache.pig.piggybank.evaluation.ExtremalTupleByNthField$HelperClass' with
arguments 'null'
at
org.apache.pig.impl.PigContext.instantiateFuncFromSpec(PigContext.java:498)
at org.apache.pig.EvalFunc.getReturnTypeFromSpec(EvalFunc.java:136)
at org.apache.pig.EvalFunc.<init>(EvalFunc.java:123)
at
org.apache.pig.piggybank.evaluation.ExtremalTupleByNthField.<init>(ExtremalTupleByNthField.java:77)
at
org.apache.pig.piggybank.evaluation.TestExtremalTupleByNthField.testMin(Unknown
Source)
Caused by: java.lang.InstantiationException:
org.apache.pig.piggybank.evaluation.ExtremalTupleByNthField$HelperClass
at java.lang.Class.newInstance0(Class.java:340)
at java.lang.Class.newInstance(Class.java:308)
at
org.apache.pig.impl.PigContext.instantiateFuncFromSpec(PigContext.java:468)
{quote}
Basically, I think it's not able to construct because the class can only be
constructed from an instance of ExtremalTupleByNthField.
{code}
ExtremalTupleByNthField etbnf = new ExtremalTupleByNthField("1","max");
etbnf.new ExtremalTupleByNthField.HelperClass();
{code}
So my solution to this problem was to make this class static. But make it so
that EvalFunc can take a vararg that will eventually contain the actual
parameters.
the handleChildConstructorParameters method in the EvalFunc will construct a
string that represents the call into the initial/intermediate/final methods but
it contains parameters that came from the ExtremalTupleByNthField.
> unable to set outgoing format for
> org.apache.pig.piggybank.evaluation.util.apachelogparser.DateExtractor
> --------------------------------------------------------------------------------------------------------
>
> Key: PIG-1303
> URL: https://issues.apache.org/jira/browse/PIG-1303
> Project: Pig
> Issue Type: Bug
> Affects Versions: 0.6.0
> Environment: pig 0.6.0 on a fedora linux machine, jdk 1.6 u11
> Reporter: Johannes Rußek
> Assignee: Dmitriy V. Ryaboy
> Attachments: TypeCheckingVisitor.java.diff
>
>
> I'm unable to set the format of the outgoing date string in the constructor
> as it's supposed to work.
> The only way i could change the format was to change the default in the java
> class and rebuild piggybank.
> Apparently this has something to do with the way pig instantiates
> DateExtractor, quoting a replier on the mailing list:
> David Vrensk said:
> I ran into the same problem a couple of weeks ago, and
> played around with the code inserting some print/log statements. It turns
> out that the arguments are only used in the initial constructor calls, when
> the pig process is starting, but once pig reaches the point where it would
> use the udf, it creates new DateExtractors without passing the arguments.
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