[pylucene-dev] weird exception java.lang.ClassCastException

[Andi Vajda]

That you dynamically check the type of the instances you serialize.

Andi..

On Sat, 5 Feb 2005, Yura Smolsky wrote:

> Hello, Andi.
>
> Well, what do you suggest? ;)
>
> AV> FieldDoc is a subclass of ScoreDoc. If the java code expects that the
> AV> scoreDocs array in the TopFieldDocs instance, which is declared as
> AV> ScoreDoc[], is actually containing FieldDoc instances and if that fact gets
> AV> lost during serialization/deserialization, then you get exactly that error
> AV> when java downcasts the ScoreDoc instance to a FieldDoc.
>
> AV> Basically, I'm saying that you cannot statically expect the scoreDocs array in
> AV> a TopFieldDocs instance to contain just ScoreDoc instances, it actually tends
> AV> to contain FieldDoc instances, which is legal since FieldDoc is a subclass of
> AV> ScoreDoc.
>
> AV> Andi..
>
> AV> On Sat, 5 Feb 2005, Yura Smolsky wrote:
>
>>> Hello, Yura.
>>>
>>> I have found that problem is about initialization of ScoreDoc object.
>>> When I use existent ScoreDoc object created by java then everything is
>>> okay. When I use ScoreDoc object created in python -> it produces
>>> exception.
>>>
>>> Check new attach.
>>>
>>> YS> Hello, Andi.
>>>
>>> YS> I just have added TopFieldDocs manual creation code. This code does
>>> YS> recreate TopFieldDocs object using PyLucene classes ScoreDoc,
>>> YS> SortField and TopFieldDocs. Check attached file.
>>> YS> This example returns exeption:
>>>
>>> YS> D:\workshop\blogz-src>d:\work\python24\python.exe RemoteSearch2.py
>>> YS> in searchSorted
>>> YS> ['"modified"!']
>>> YS> 249 1.0
>>> YS> 269 0.282842695713
>>> YS> 4 0.34999999404
>>> YS> 52 0.17499999702
>>> YS> modified 3 True
>>> YS> in searchSorted, finished
>>> YS> Exception in thread "MultiSearcher thread #1"
>>> YS> java.lang.ClassCastException: org.apache.lucene.search.ScoreDoc
>>> YS> cannot be cast to
>>> YS> org.apache.lucene.search.FieldDoc
>>> YS> *** Got java.lang.NullPointerException while trying to print stack trace.
>>> YS> 4
>>>
>>> AV>> I verified, by modifying the RemoteSearcher.py code you sent me yesterday that
>>> AV>> 'searchSorted' is working properly. The code is attached.
>>>
>>> AV>> Andi..
>>>
>>> AV>> On Sat, 5 Feb 2005, Yura Smolsky wrote:
>>>
>>>>>> Hello, pylucene-dev.
>>>>>>
>>>>>> I use ParallelMultiSearcher and I construct manually variables passed
>>>>>> to search, searchSorted methods of Searchable implementation.
>>>>>> I got this exception when I use sort and ParallerMultiSearcher:
>>>>>>
>>>>>> scoreDoc: 261
>>>>>> scoreDoc: 211
>>>>>> ... skipped ...
>>>>>> scoreDoc: 142
>>>>>> scoreDoc: 144
>>>>>> Exception in thread "MultiSearcher thread #1"
>>>>>> java.lang.ClassCastException: org.apache.lucene.search.ScoreDoc
>>>>>> cannot be cast to
>>>>>> org.apache.lucene.search.FieldDoc
>>>>>>   at 0x012ce0ae (Unknown Source)
>>>>>>   ... skipped
>>>>>> hits: 18
>>>>>>
>>>>>> if I do not use sort or if I use Searchable implementation through
>>>>>> searchSorted then everything is ok.
>>>>>> I do not understand this.. Who is messing the data?..
>>>>>> Maybe method searchSorted of implementation of Searchable generates
>>>>>> "bad" PyLucene classes?..
>>>>>>
>>>>>> Thanks in advance.
>>>>>>
>>>>>> Yura Smolsky
>>> AV>>
>>>
>>>
>>>
>>> YS> Yura Smolsky,
>>> YS>
>>>
>>>
>>>
>>> Yura Smolsky,
>
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> AV>
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> Yura Smolsky,
>
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