DiffNrOfCharactersPairFeatureExtractor extends FeatureExtractorResource_ImplBase implements PairFeatureExtractor { @Override public Set<Feature> extract(JCas view1, JCas view2) throws TextClassificationException { return new Feature("DiffNrOfCharacters", view1.getDocumentText().length() - view2.getDocumentText().length(), FeatureType.NUMERIC).asSet(); }  @Override Set<Feature> extract(JCas view1, JCas view2);  }
@Test public void testExtract() throws ResourceInitializationException, AnalysisEngineProcessException, TextClassificationException { AnalysisEngineDescription desc = createEngineDescription(BreakIteratorSegmenter.class); AnalysisEngine engine = createEngine(desc); JCas jcas1 = engine.newJCas(); jcas1.setDocumentLanguage("en"); jcas1.setDocumentText("This is the text of view 1. And some more."); engine.process(jcas1); JCas jcas2 = engine.newJCas(); jcas2.setDocumentLanguage("en"); jcas2.setDocumentText("This is the text of view 2"); engine.process(jcas2); DiffNrOfCharactersPairFeatureExtractor extractor = new DiffNrOfCharactersPairFeatureExtractor(); Set<Feature> features = extractor.extract(jcas1, jcas2); assertEquals(1, features.size()); for (Feature feature : features) { assertFeature("DiffNrOfCharacters", 16, feature); } }