Re: Stuck with class ChunkerME: java.lang.String cannot be cast to opennlp.tools.parser.Parse

[ttr...@nlke-group.net]

Dear Apache OpenNLP Project Team,

I have another error with command line tool:
    - I did exactly as information in site 
(https://opennlp.apache.org/documentation/1.6.0/manual/opennlp.html#tools.chunker.training.tool):

E:\test\apache-opennlp-1.5.3\bin>opennlp.bat ChunkerTrainerME -model 
E:\test\en-chunker.bin -lang en -data E:\test\tmp.txt -encoding UTF-8

File test only contains sample sentence as in the site :

He        PRP  B-NP
reckons   VBZ  B-VP
the       DT   B-NP
current   JJ   I-NP
account   NN   I-NP
deficit   NN   I-NP
will      MD   B-VP
narrow    VB   I-VP
to        TO   B-PP
only      RB   B-NP
#         #    I-NP
1.8       CD   I-NP
billion   CD   I-NP
in        IN   B-PP
September NNP  B-NP
.         .    O

And here is the error:

        Computing event counts...  done. 0 events
        Indexing...  done.
Sorting and merging events... Done indexing.
Incorporating indexed data for training...
Exception in thread "main" java.lang.NullPointerException
        at opennlp.maxent.GISTrainer.trainModel(GISTrainer.java:263)
        at opennlp.maxent.GIS.trainModel(GIS.java:256)
        at opennlp.model.TrainUtil.train(TrainUtil.java:184)
        at opennlp.tools.chunker.ChunkerME.train(ChunkerME.java:214)
        at 
opennlp.tools.cmdline.chunker.ChunkerTrainerTool.run(ChunkerTrainerTo
ol.java:68)
        at opennlp.tools.cmdline.CLI.main(CLI.java:222)


Another point: The function cannot read more than 2 sentence in one 
train file.

Would you please check these points for me?

Thank you so much for your help.

Best regards,

Trung Tran.

On 05/17/2016 02:06 PM, ttr...@nlke-group.net wrote:
Dear Apache OpenNLP Project Team,

I have an critical issue when training with Chunker tool in Java:

    - Firstly, the sample code in documentation site 
(https://opennlp.apache.org/documentation/1.6.0/manual/opennlp.html#tools.chunker.training.api) 
is not work, both for version 1.5.3 and 1.6.0

    - Secondly, I have to edit the codes myself to (using version 1.5.3):

try {
            Charset charset = Charset.forName("UTF-8");
            ObjectStream lineStream = new PlainTextByLineStream(new 
FileInputStream(fileChunker), charset);
            ObjectStream<ChunkSample> sampleStream = new 
ChunkSampleStream(lineStream);

            chunkerModel = ChunkerME.train("vn", sampleStream, 
TrainingParameters.defaultParams(), new ChunkerFactory());

            modelApacheChunkerPath = 
UtilityHelper.getTemporaryFilePathInsideDir("chunkerModel.bin");
            OutputStream modelOut = new BufferedOutputStream(new 
FileOutputStream(modelApacheChunkerPath));
            chunkerModel.serialize(modelOut);
        } catch (FileNotFoundException fe) {

        } catch (IOException ie) {

        }

    - Thirdly, I have the error "java.lang.String cannot be cast to 
opennlp.tools.parser.Parse". The reason is:

            + The constructor of class ChunkSampleStream requires 
parameter is "ObjectStream<Parse> in"

            + However, the second parameter of method ChunkerME.train 
is "ObjectStream<ChunkSample> in"

I cannot find any way to work around this issue.

Would you please check this point for me?

Thank you so much for your help.

Best regards,

Trung Tran.