[OPENNLP-238] BestSequence method in BeamSearch can cause NullPointerException if it can not find a valid sequence

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: tools-1.5.2-incubating
• Component/s: POS Tagger
• Assignee: William Colen
• Reporter: William Colen
• Created: 26/Jul/11 03:11
• Updated: 09/Aug/11 08:28
• Resolved: 09/Aug/11 08:28

Description

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.

Issue Links

• relates to: OPENNLP-241 Model validations is only performed if instatiated from Input Stream.