[
https://issues.apache.org/jira/browse/OPENNLP-238?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13072815#comment-13072815
]
Jörn Kottmann commented on OPENNLP-238:
---------------------------------------
I observed a similar issue once, there the tagdict restricted the outcome to
outcomes which are not in the model. Therefore the sequence validator returned
false on all possible sequences, and the beam searchs bestSequence then
returned null.
I am not sure if we have now a check in the POS Model, to fail if the tagdict
contains such invalid outcomes, but if I remember correctly there is at least a
jira for that.
> BestSequence method in BeamSearch can cause NullPointerException if it can
> not find a valid sequence
> ----------------------------------------------------------------------------------------------------
>
> Key: OPENNLP-238
> URL: https://issues.apache.org/jira/browse/OPENNLP-238
> Project: OpenNLP
> Issue Type: Bug
> Components: POS Tagger
> Affects Versions: tools-1.5.2-incubating
> Reporter: William Colen
> Assignee: William Colen
> Fix For: tools-1.5.2-incubating
>
>
> I am using the standard sequence validator of POS Tagger with a
> TagDictionary. Sometimes there are no outcome that matches with the tags in
> the dictionary. That is causing a NullPointerException in bestSequence method.
> I think we should add an extra validation: if the heap 'next' still empty
> after advancing all valid sequences (line 159) we should let it advance
> invalid sequences. It would make the POS Tagger more robust.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
