org.apache.uima.examples.tagger

Class HMMTagger

java.lang.Object

org.apache.uima.analysis_component.AnalysisComponent_ImplBase

org.apache.uima.analysis_component.Annotator_ImplBase

org.apache.uima.analysis_component.JCasAnnotator_ImplBase

org.apache.uima.examples.tagger.HMMTagger

All Implemented Interfaces:

org.apache.uima.analysis_component.AnalysisComponent, Tagger

public class HMMTagger
extends org.apache.uima.analysis_component.JCasAnnotator_ImplBase
implements Tagger

UIMA Analysis Engine that invokes HMM POS tagger. HMM POS tagger generates part-of-speech tags for every token. This annotator assumes that sentences and tokens have already been annotated in the CAS with Sentence and Token annotations, respectively. We iterate over sentences, then iterate over tokens in the current sentence to accumulate a list of words, then invoke the HMM POS tagger on the list of words. For each Token we then update the posTag field with the POS tag. The model file for the HMM POS tagger is specified as a parameter (MODEL_FILE_PARAM).

The configuration of this analysis engine is done through several parameters:

• InputView: - the view to process
• SentenceType: the annotation type which covers token annotations
• TokenFeaturePath: - feature path to the token feature to be tagged. The annotation should exactly cover a "word".
• ModelFile: - the path from where the model will be read

Field Summary

Fields

Modifier and Type	Field and Description
ModelGeneration	my_model
int	N for a bigram model: N = 2, for a trigram model N=3 N is defined in parameter file
static java.lang.String	PARAM_IMPORT_MODEL_FILE Name of the parameter for the model import path
static java.lang.String	PARAM_INPUT_VIEW Name of the parameter for the input view
static java.lang.String	PARAM_SENTENCE Name of the parameter for the annotation type which covers token annotations
static java.lang.String	PARAM_TOKEN_FP Name of the parameter for the feature path to the token feature to be tagged

Constructor Summary

Constructors

Constructor and Description
HMMTagger()

Method Summary

Methods

Modifier and Type	Method and Description
static ModelGeneration	get_model(java.lang.String filename) Reads a saved MODEL object from a file
static org.apache.uima.cas.Type	getType(org.apache.uima.jcas.JCas aJCas, java.lang.String annotationString) Get the type of a given annotation name and check if it exists
void	initialize(org.apache.uima.UimaContext aContext) Initialize the Annotator.
void	process(org.apache.uima.jcas.JCas aJCas) Process a CAS.

Methods inherited from class org.apache.uima.analysis_component.JCasAnnotator_ImplBase

getRequiredCasInterface, process

Methods inherited from class org.apache.uima.analysis_component.Annotator_ImplBase

getCasInstancesRequired, hasNext, next

Methods inherited from class org.apache.uima.analysis_component.AnalysisComponent_ImplBase

batchProcessComplete, collectionProcessComplete, destroy, getContext, getResultSpecification, reconfigure, setResultSpecification

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PARAM_INPUT_VIEW

public static java.lang.String PARAM_INPUT_VIEW

Name of the parameter for the input view

PARAM_IMPORT_MODEL_FILE

public static java.lang.String PARAM_IMPORT_MODEL_FILE

Name of the parameter for the model import path

PARAM_SENTENCE

public static java.lang.String PARAM_SENTENCE

Name of the parameter for the annotation type which covers token annotations

PARAM_TOKEN_FP

public static java.lang.String PARAM_TOKEN_FP

Name of the parameter for the feature path to the token feature to be tagged

N

public int N

for a bigram model: N = 2, for a trigram model N=3 N is defined in parameter file

my_model

public ModelGeneration my_model

Constructor Detail

HMMTagger

public HMMTagger()

Method Detail

initialize

public void initialize(org.apache.uima.UimaContext aContext)
                throws org.apache.uima.resource.ResourceInitializationException

Initialize the Annotator.

Specified by:

initialize in interface org.apache.uima.analysis_component.AnalysisComponent

Specified by:

initialize in interface Tagger

Overrides:

initialize in class org.apache.uima.analysis_component.AnalysisComponent_ImplBase

Throws:

org.apache.uima.resource.ResourceInitializationException

See Also:

AnalysisComponent_ImplBase.initialize(UimaContext)

get_model

public static ModelGeneration get_model(java.lang.String filename)

Reads a saved MODEL object from a file

Parameters:

filename - model file

Returns:

ModelGeneration

process

public void process(org.apache.uima.jcas.JCas aJCas)
             throws org.apache.uima.analysis_engine.AnalysisEngineProcessException

Process a CAS.

Specified by:

process in interface Tagger

Specified by:

process in class org.apache.uima.analysis_component.JCasAnnotator_ImplBase

Throws:

org.apache.uima.analysis_engine.AnalysisEngineProcessException

See Also:

JCasAnnotator_ImplBase.process(JCas)

getType

public static org.apache.uima.cas.Type getType(org.apache.uima.jcas.JCas aJCas,
                               java.lang.String annotationString)
                                        throws org.apache.uima.analysis_engine.AnalysisEngineProcessException

Get the type of a given annotation name and check if it exists

Parameters:

aJCas -

annotationString -

Returns:

annotationType

Throws:

org.apache.uima.analysis_engine.AnalysisEngineProcessException