new CharacterCategoryPatternExtractor(PatternType.ONE_PER_CHAR),
new TypePathExtractor(BaseToken.class, "partOfSpeech"));
this.contextFeatureExtractor = new CleartkExtractor(
BaseToken.class,
this.tokenFeatureExtractor,
new Preceding(3),
new Following(3));
if (featureSelectionThreshold < 0) {
this.featureSelection = null;
} else {