org.apache.spark.ml.feature.StringIndexerModel Java Examples

@Override
public StringIndexerModelInfo getModelInfo(final StringIndexerModel from) {
    final String[] labels = from.labels();
    final Map<String, Double> labelToIndex = new HashMap<String, Double>();
    for (int i = 0; i < labels.length; i++) {
        labelToIndex.put(labels[i], (double) i);
    }
    final StringIndexerModelInfo modelInfo = new StringIndexerModelInfo();
    modelInfo.setLabelToIndex(labelToIndex);

    Set<String> inputKeys = new LinkedHashSet<String>();
    inputKeys.add(from.getInputCol());
    modelInfo.setInputKeys(inputKeys);

    Set<String> outputKeys = new LinkedHashSet<String>();
    outputKeys.add(from.getOutputCol());
    modelInfo.setOutputKeys(outputKeys);

    return modelInfo;
}
 

@Override
public StringIndexerModelInfo getModelInfo(final StringIndexerModel from, DataFrame df) {
    final String[] labels = from.labels();
    final Map<String, Double> labelToIndex = new HashMap<String, Double>();
    for (int i = 0; i < labels.length; i++) {
        labelToIndex.put(labels[i], (double) i);
    }
    final StringIndexerModelInfo modelInfo = new StringIndexerModelInfo();
    modelInfo.setLabelToIndex(labelToIndex);

    Set<String> inputKeys = new LinkedHashSet<String>();
    inputKeys.add(from.getInputCol());
    modelInfo.setInputKeys(inputKeys);

    Set<String> outputKeys = new LinkedHashSet<String>();
    outputKeys.add(from.getOutputCol());
    modelInfo.setOutputKeys(outputKeys);

    return modelInfo;
}
 

public static void main(String[] args) {
  SparkSession spark = SparkSession
    .builder()
    .appName("JavaOneHotEncoderExample")
    .getOrCreate();

  // $example on$
  List<Row> data = Arrays.asList(
    RowFactory.create(0, "a"),
    RowFactory.create(1, "b"),
    RowFactory.create(2, "c"),
    RowFactory.create(3, "a"),
    RowFactory.create(4, "a"),
    RowFactory.create(5, "c")
  );

  StructType schema = new StructType(new StructField[]{
    new StructField("id", DataTypes.IntegerType, false, Metadata.empty()),
    new StructField("category", DataTypes.StringType, false, Metadata.empty())
  });

  Dataset<Row> df = spark.createDataFrame(data, schema);

  StringIndexerModel indexer = new StringIndexer()
    .setInputCol("category")
    .setOutputCol("categoryIndex")
    .fit(df);
  Dataset<Row> indexed = indexer.transform(df);

  OneHotEncoder encoder = new OneHotEncoder()
    .setInputCol("categoryIndex")
    .setOutputCol("categoryVec");

  Dataset<Row> encoded = encoder.transform(indexed);
  encoded.show();
  // $example off$

  spark.stop();
}
 

/**
 * Creates a conditional Markov model.
 * @param pipelineModel
 * @param weights
 * @param markovOrder
 */
public CMMModel(PipelineModel pipelineModel, Vector weights, MarkovOrder markovOrder, Map<String, Set<Integer>> tagDictionary) {
	this.pipelineModel = pipelineModel;
	this.contextExtractor = new ContextExtractor(markovOrder, Constants.REGEXP_FILE);
	this.weights = weights;
	this.tags = ((StringIndexerModel)(pipelineModel.stages()[2])).labels();
	String[] features = ((CountVectorizerModel)(pipelineModel.stages()[1])).vocabulary();
	featureMap = new HashMap<String, Integer>();
	for (int j = 0; j < features.length; j++) {
		featureMap.put(features[j], j);
	}
	this.tagDictionary = tagDictionary;
}
 

/**
 * Creates a transition-based parser using a MLP transition classifier.
 * @param jsc
 * @param classifierFileName
 * @param featureFrame
 */
public TransitionBasedParserMLP(JavaSparkContext jsc, String classifierFileName, FeatureFrame featureFrame) {
	this.featureFrame = featureFrame;
	this.classifier = TransitionClassifier.load(jsc, new Path(classifierFileName, "data").toString());
	this.pipelineModel = PipelineModel.load(new Path(classifierFileName, "pipelineModel").toString());
	this.transitionName = ((StringIndexerModel)pipelineModel.stages()[2]).labels();
	String[] features = ((CountVectorizerModel)(pipelineModel.stages()[1])).vocabulary();
	this.featureMap = new HashMap<String, Integer>();
	for (int j = 0; j < features.length; j++) {
		this.featureMap.put(features[j], j);
	}
	
}
 

@Test
public void testStringIndexer() {

    //prepare data
    StructType schema = createStructType(new StructField[]{
            createStructField("id", IntegerType, false),
            createStructField("label", StringType, false)
    });
    List<Row> trainingData = Arrays.asList(
            cr(0, "a"), cr(1, "b"), cr(2, "c"), cr(3, "a"), cr(4, "a"), cr(5, "c"));
    Dataset<Row> dataset = spark.createDataFrame(trainingData, schema);

    //train model in spark
    StringIndexerModel model = new StringIndexer()
            .setInputCol("label")
            .setOutputCol("labelIndex").fit(dataset);

    //Export this model
    byte[] exportedModel = ModelExporter.export(model);

    //Import and get Transformer
    Transformer transformer = ModelImporter.importAndGetTransformer(exportedModel);

    //compare predictions
    List<Row> sparkOutput = model.transform(dataset).orderBy("id").select("id", "label", "labelIndex").collectAsList();
    for (Row row : sparkOutput) {

        Map<String, Object> data = new HashMap<String, Object>();
        data.put(model.getInputCol(), (String) row.get(1));
        transformer.transform(data);
        double output = (double) data.get(model.getOutputCol());

        double indexerOutput = (output);
        assertEquals(indexerOutput, (double) row.get(2), 0.01);
    }

}
 

@Test(expected=RuntimeException.class)
public void testStringIndexerForUnseenValues() {

    //prepare data
    StructType schema = createStructType(new StructField[]{
            createStructField("id", IntegerType, false),
            createStructField("label", DoubleType, false)
    });
    List<Row> trainingData = Arrays.asList(
            cr(0, 1.0), cr(1, 2.0), cr(2, 3.0), cr(3, 1.0), cr(4, 1.0), cr(5, 3.0));
    DataFrame dataset = sqlContext.createDataFrame(trainingData, schema);

    //train model in spark
    StringIndexerModel model = new StringIndexer()
            .setInputCol("label")
            .setOutputCol("labelIndex").fit(dataset);

    //Export this model
    byte[] exportedModel = ModelExporter.export(model, dataset);

    //Import and get Transformer
    Transformer transformer = ModelImporter.importAndGetTransformer(exportedModel);

    //unseen value
    Map<String, Object> data = new HashMap<String, Object>();
    data.put(model.getInputCol(), 7.0);
    transformer.transform(data);
}
 

@Test
public void testStringIndexerForDoubleColumn() {

    //prepare data
    StructType schema = createStructType(new StructField[]{
            createStructField("id", IntegerType, false),
            createStructField("label", DoubleType, false)
    });
    List<Row> trainingData = Arrays.asList(
            cr(0, 1.0), cr(1, 2.0), cr(2, 3.0), cr(3, 1.0), cr(4, 1.0), cr(5, 3.0));
    DataFrame dataset = sqlContext.createDataFrame(trainingData, schema);

    //train model in spark
    StringIndexerModel model = new StringIndexer()
            .setInputCol("label")
            .setOutputCol("labelIndex").fit(dataset);

    //Export this model
    byte[] exportedModel = ModelExporter.export(model, dataset);

    //Import and get Transformer
    Transformer transformer = ModelImporter.importAndGetTransformer(exportedModel);

    //compare predictions
    Row[] sparkOutput = model.transform(dataset).orderBy("id").select("id", "label", "labelIndex").collect();
    for (Row row : sparkOutput) {

        Map<String, Object> data = new HashMap<String, Object>();
        data.put(model.getInputCol(), row.getDouble(1));
        transformer.transform(data);
        double indexerOutput = (double) data.get(model.getOutputCol());
        assertEquals(indexerOutput, row.getDouble(2), EPSILON);
    }

}
 

@Test
public void testStringIndexer() {

    //prepare data
    StructType schema = createStructType(new StructField[]{
            createStructField("id", IntegerType, false),
            createStructField("label", StringType, false)
    });
    List<Row> trainingData = Arrays.asList(
            cr(0, "a"), cr(1, "b"), cr(2, "c"), cr(3, "a"), cr(4, "a"), cr(5, "c"));
    DataFrame dataset = sqlContext.createDataFrame(trainingData, schema);

    //train model in spark
    StringIndexerModel model = new StringIndexer()
            .setInputCol("label")
            .setOutputCol("labelIndex").fit(dataset);

    //Export this model
    byte[] exportedModel = ModelExporter.export(model, dataset);

    //Import and get Transformer
    Transformer transformer = ModelImporter.importAndGetTransformer(exportedModel);

    //compare predictions
    Row[] sparkOutput = model.transform(dataset).orderBy("id").select("id", "label", "labelIndex").collect();
    for (Row row : sparkOutput) {

        Map<String, Object> data = new HashMap<String, Object>();
        data.put(model.getInputCol(), (String) row.get(1));
        transformer.transform(data);
        double indexerOutput = (double) data.get(model.getOutputCol());

        assertEquals(indexerOutput, (double) row.get(2), EPSILON);
    }

}
 

@Test
public void testDecisionTreeClassificationRawPrediction() {
    // Load the data stored in LIBSVM format as a DataFrame.
    DataFrame data = sqlContext.read().format("libsvm").load("src/test/resources/classification_test.libsvm");

    StringIndexerModel stringIndexerModel = new StringIndexer()
            .setInputCol("label")
            .setOutputCol("labelIndex")
            .fit(data);

    data = stringIndexerModel.transform(data);

    // Split the data into training and test sets (30% held out for testing)
    DataFrame[] splits = data.randomSplit(new double[]{0.7, 0.3});
    DataFrame trainingData = splits[0];
    DataFrame testData = splits[1];

    // Train a DecisionTree model.
    DecisionTreeClassificationModel classificationModel = new DecisionTreeClassifier()
            .setLabelCol("labelIndex")
            .setFeaturesCol("features")
            .setRawPredictionCol("rawPrediction")
            .setPredictionCol("prediction")
            .fit(trainingData);

    byte[] exportedModel = ModelExporter.export(classificationModel, null);

    Transformer transformer = (DecisionTreeTransformer) ModelImporter.importAndGetTransformer(exportedModel);

    Row[] sparkOutput = classificationModel.transform(testData).select("features", "prediction", "rawPrediction").collect();

    //compare predictions
    for (Row row : sparkOutput) {
        Vector inp = (Vector) row.get(0);
        double actual = row.getDouble(1);
        double[] actualRaw = ((Vector) row.get(2)).toArray();

        Map<String, Object> inputData = new HashMap<>();
        inputData.put(transformer.getInputKeys().iterator().next(), inp.toArray());
        transformer.transform(inputData);
        double predicted = (double) inputData.get(transformer.getOutputKeys().iterator().next());
        double[] rawPrediction = (double[]) inputData.get("rawPrediction");

        assertEquals(actual, predicted, EPSILON);
        assertArrayEquals(actualRaw, rawPrediction, EPSILON);
    }
}
 

/**
 * Dataset must at least contain the following two columns:
 * label: the class labels
 * features: feature vector
 * @param data
 * @return map with metrics
 */
public Map<String,String> fit(Dataset<Row> data) {
	int classCount = (int)data.select(label).distinct().count();

	StringIndexerModel labelIndexer = new StringIndexer()
	  .setInputCol(label)
	  .setOutputCol("indexedLabel")
	  .fit(data);

	// Split the data into training and test sets (30% held out for testing)
	Dataset<Row>[] splits = data.randomSplit(new double[] {1.0-testFraction, testFraction}, seed);
	Dataset<Row> trainingData = splits[0];
	Dataset<Row> testData = splits[1];
	
	String[] labels = labelIndexer.labels();
	
	System.out.println();
	System.out.println("Class\tTrain\tTest");
	for (String l: labels) {
		System.out.println(l + "\t" + trainingData.select(label).filter(label + " = '" + l + "'").count()
				+ "\t" 
				+ testData.select(label).filter(label + " = '" + l + "'").count());
	}
	
	// Set input columns
	predictor
	.setLabelCol("indexedLabel")
	.setFeaturesCol("features");

	// Convert indexed labels back to original labels.
	IndexToString labelConverter = new IndexToString()
	  .setInputCol("prediction")
	  .setOutputCol("predictedLabel")
	  .setLabels(labelIndexer.labels());

	// Chain indexers and forest in a Pipeline
	Pipeline pipeline = new Pipeline()
	  .setStages(new PipelineStage[] {labelIndexer, predictor, labelConverter});

	// Train model. This also runs the indexers.
	PipelineModel model = pipeline.fit(trainingData);

	// Make predictions.
	Dataset<Row> predictions = model.transform(testData).cache();
	
	// Display some sample predictions
	System.out.println();
	System.out.println("Sample predictions: " + predictor.getClass().getSimpleName());

	predictions.sample(false, 0.1, seed).show(25);	

	predictions = predictions.withColumnRenamed(label, "stringLabel");
	predictions = predictions.withColumnRenamed("indexedLabel", label);
	
	// collect metrics
	Dataset<Row> pred = predictions.select("prediction",label);
       Map<String,String> metrics = new LinkedHashMap<>();       
       metrics.put("Method", predictor.getClass().getSimpleName());
       
       if (classCount == 2) {
       	    BinaryClassificationMetrics b = new BinaryClassificationMetrics(pred);
         	metrics.put("AUC", Float.toString((float)b.areaUnderROC()));
       }
    
       MulticlassMetrics m = new MulticlassMetrics(pred); 
       metrics.put("F", Float.toString((float)m.weightedFMeasure()));
       metrics.put("Accuracy", Float.toString((float)m.accuracy()));
       metrics.put("Precision", Float.toString((float)m.weightedPrecision()));
       metrics.put("Recall", Float.toString((float)m.weightedRecall()));
       metrics.put("False Positive Rate", Float.toString((float)m.weightedFalsePositiveRate()));
       metrics.put("True Positive Rate", Float.toString((float)m.weightedTruePositiveRate()));
       metrics.put("", "\nConfusion Matrix\n" 
           + Arrays.toString(labels) +"\n" 
       		+ m.confusionMatrix().toString());
       
       return metrics;
}
 

@Test
public void testRandomForestClassification() {
    // Load the data stored in LIBSVM format as a DataFrame.
    DataFrame data = sqlContext.read().format("libsvm").load("src/test/resources/classification_test.libsvm");

    StringIndexerModel stringIndexerModel = new StringIndexer()
            .setInputCol("label")
            .setOutputCol("labelIndex")
            .fit(data);

    data = stringIndexerModel.transform(data);

    // Split the data into training and test sets (30% held out for testing)
    DataFrame[] splits = data.randomSplit(new double[]{0.7, 0.3});
    DataFrame trainingData = splits[0];
    DataFrame testData = splits[1];

    // Train a RandomForest model.
    RandomForestClassificationModel classificationModel = new RandomForestClassifier()
            .setLabelCol("labelIndex")
            .setFeaturesCol("features")
            .setPredictionCol("prediction")
            .setRawPredictionCol("rawPrediction")
            .setProbabilityCol("probability")
            .fit(trainingData);


    byte[] exportedModel = ModelExporter.export(classificationModel, null);

    Transformer transformer = ModelImporter.importAndGetTransformer(exportedModel);

    Row[] sparkOutput = classificationModel.transform(testData).select("features", "prediction", "rawPrediction", "probability").collect();

    //compare predictions
    for (Row row : sparkOutput) {
        Vector v = (Vector) row.get(0);
        double actual = row.getDouble(1);
        double [] actualProbability = ((Vector) row.get(3)).toArray();
        double[] actualRaw = ((Vector) row.get(2)).toArray();

        Map<String, Object> inputData = new HashMap<String, Object>();
        inputData.put(transformer.getInputKeys().iterator().next(), v.toArray());
        transformer.transform(inputData);
        double predicted = (double) inputData.get("prediction");
        double[] probability = (double[]) inputData.get("probability");
        double[] rawPrediction = (double[]) inputData.get("rawPrediction");

        assertEquals(actual, predicted, EPSILON);
        assertArrayEquals(actualProbability, probability, EPSILON);
        assertArrayEquals(actualRaw, rawPrediction, EPSILON);


    }

}
 

@Test
public void testStringIndexerForHandlingUnseenValues() {

    //prepare data
    StructType schema = createStructType(new StructField[]{
            createStructField("id", IntegerType, false),
            createStructField("label", DoubleType, false)
    });
    List<Row> trainingData = Arrays.asList(
            cr(0, 1.0), cr(1, 2.0), cr(2, 3.0), cr(3, 1.0), cr(4, 1.0), cr(5, 3.0));
    DataFrame dataset = sqlContext.createDataFrame(trainingData, schema);

    //train model in spark
    StringIndexerModel model = new StringIndexer()
            .setInputCol("label")
            .setOutputCol("labelIndex").fit(dataset);

    //Export this model
    byte[] exportedModel = ModelExporter.export(model, dataset);

    StringIndexerModelInfo stringIndexerModelInfo = (StringIndexerModelInfo)ModelImporter.importModelInfo(exportedModel);
    stringIndexerModelInfo.setFailOnUnseenValues(false);

    //Import and get Transformer
    Transformer transformer = stringIndexerModelInfo.getTransformer();

    //unseen value
    Map<String, Object> data = new HashMap<String, Object>();
    data.put(model.getInputCol(), 7.0);
    transformer.transform(data);
    double indexerOutput = (double) data.get(model.getOutputCol());
    assertEquals(indexerOutput, 3.0, EPSILON);

    //unseen value
    data.put(model.getInputCol(), 9.0);
    transformer.transform(data);
    indexerOutput = (double) data.get(model.getOutputCol());
    assertEquals(indexerOutput, 3.0, EPSILON);

    //unseen value
    data.put(model.getInputCol(), 0.0);
    transformer.transform(data);
    indexerOutput = (double) data.get(model.getOutputCol());
    assertEquals(indexerOutput, 3.0, EPSILON);

    //seen value
    data.put(model.getInputCol(), 2.0);
    transformer.transform(data);
    indexerOutput = (double) data.get(model.getOutputCol());
    assertEquals(indexerOutput, stringIndexerModelInfo.getLabelToIndex().get("2.0"), EPSILON);
}
 

@Test
public void testCustomOneHotEncoding() {
    // prepare data
    JavaRDD<Row> jrdd = sc.parallelize(Arrays.asList(
            RowFactory.create(0d, "a"),
            RowFactory.create(1d, "b"),
            RowFactory.create(2d, "c"),
            RowFactory.create(3d, "a"),
            RowFactory.create(4d, "a"),
            RowFactory.create(5d, "c")
    ));

    StructType schema = new StructType(new StructField[]{
            new StructField("id", DataTypes.DoubleType, false, Metadata.empty()),
            new StructField("category", DataTypes.StringType, false, Metadata.empty())
    });

    DataFrame df = sqlContext.createDataFrame(jrdd, schema);
    StringIndexerModel indexer = new StringIndexer()
            .setInputCol("category")
            .setOutputCol("categoryIndex")
            .fit(df);
    DataFrame indexed = indexer.transform(df);

    CustomOneHotEncoderModel sparkModel = new CustomOneHotEncoder()
            .setInputCol("categoryIndex")
            .setOutputCol("categoryVec")
            .fit(indexed);

    //Export this model
    byte[] exportedModel = ModelExporter.export(sparkModel, indexed);

    //Create spark's OneHotEncoder
    OneHotEncoder sparkOneHotModel = new OneHotEncoder()
            .setInputCol("categoryIndex")
            .setOutputCol("categoryVec");

    //Import and get Transformer
    Transformer transformer = ModelImporter.importAndGetTransformer(exportedModel);

    //compare predictions
    Row[] sparkOutput = sparkModel.transform(indexed).orderBy("id").select("id", "categoryIndex", "categoryVec").collect();
    Row[] sparkOneHotOutput = sparkOneHotModel.transform(indexed).orderBy("id").select("id", "categoryIndex", "categoryVec").collect();

    //Compare Spark's OneHotEncoder with CustomOneHotEncoder
    //See if the dictionary size is equal
    assertEquals(sparkOutput.length, sparkOneHotOutput.length);

    for (int i = 0; i < sparkOutput.length; i++) {
        Row row = sparkOutput[i];
        Map<String, Object> data = new HashMap<String, Object>();
        data.put(sparkModel.getInputCol(), row.getDouble(1));
        transformer.transform(data);
        double[] transformedOp = (double[]) data.get(sparkModel.getOutputCol());

        double[] sparkOp = ((Vector) row.get(2)).toArray();
        //get spark's OneHotEncoder output
        double[] sparkOneHotOp = ((Vector) sparkOneHotOutput[i].get(2)).toArray();
        assertArrayEquals(transformedOp, sparkOp, EPSILON);
        assertArrayEquals(sparkOneHotOp, sparkOp, EPSILON);
    }
}
 

@Test
public void testOneHotEncoding() {
    // prepare data
    JavaRDD<Row> jrdd = sc.parallelize(Arrays.asList(
            RowFactory.create(0d, "a"),
            RowFactory.create(1d, "b"),
            RowFactory.create(2d, "c"),
            RowFactory.create(3d, "a"),
            RowFactory.create(4d, "a"),
            RowFactory.create(5d, "c")
    ));

    StructType schema = new StructType(new StructField[]{
            new StructField("id", DataTypes.DoubleType, false, Metadata.empty()),
            new StructField("category", DataTypes.StringType, false, Metadata.empty())
    });

    DataFrame df = sqlContext.createDataFrame(jrdd, schema);
    StringIndexerModel indexer = new StringIndexer()
            .setInputCol("category")
            .setOutputCol("categoryIndex")
            .fit(df);
    DataFrame indexed = indexer.transform(df);

    OneHotEncoder sparkModel = new OneHotEncoder()
            .setInputCol("categoryIndex")
            .setOutputCol("categoryVec");

    //Export this model
    byte[] exportedModel = ModelExporter.export(sparkModel, indexed);

    //Import and get Transformer
    Transformer transformer = ModelImporter.importAndGetTransformer(exportedModel);

    //compare predictions
    Row[] sparkOutput = sparkModel.transform(indexed).orderBy("id").select("id", "categoryIndex", "categoryVec").collect();
    for (Row row : sparkOutput) {

        Map<String, Object> data = new HashMap<String, Object>();
        data.put(sparkModel.getInputCol(), row.getDouble(1));
        transformer.transform(data);
        double[] transformedOp = (double[]) data.get(sparkModel.getOutputCol());

        double[] sparkOp = ((Vector) row.get(2)).toArray();
        assertArrayEquals(transformedOp, sparkOp, EPSILON);
    }
}
 

@Override
public Class<StringIndexerModel> getSource() {
    return StringIndexerModel.class;
}
 

@Override
public Class<StringIndexerModel> getSource() {
    return StringIndexerModel.class;
}
 

public StringIndexerModelConverter(StringIndexerModel transformer){
	super(transformer);
}
 

public static void main(String[] args) {
  SparkSession spark = SparkSession
    .builder()
    .appName("JavaIndexToStringExample")
    .getOrCreate();

  // $example on$
  List<Row> data = Arrays.asList(
    RowFactory.create(0, "a"),
    RowFactory.create(1, "b"),
    RowFactory.create(2, "c"),
    RowFactory.create(3, "a"),
    RowFactory.create(4, "a"),
    RowFactory.create(5, "c")
  );
  StructType schema = new StructType(new StructField[]{
    new StructField("id", DataTypes.IntegerType, false, Metadata.empty()),
    new StructField("category", DataTypes.StringType, false, Metadata.empty())
  });
  Dataset<Row> df = spark.createDataFrame(data, schema);

  StringIndexerModel indexer = new StringIndexer()
    .setInputCol("category")
    .setOutputCol("categoryIndex")
    .fit(df);
  Dataset<Row> indexed = indexer.transform(df);

  System.out.println("Transformed string column '" + indexer.getInputCol() + "' " +
      "to indexed column '" + indexer.getOutputCol() + "'");
  indexed.show();

  StructField inputColSchema = indexed.schema().apply(indexer.getOutputCol());
  System.out.println("StringIndexer will store labels in output column metadata: " +
      Attribute.fromStructField(inputColSchema).toString() + "\n");

  IndexToString converter = new IndexToString()
    .setInputCol("categoryIndex")
    .setOutputCol("originalCategory");
  Dataset<Row> converted = converter.transform(indexed);

  System.out.println("Transformed indexed column '" + converter.getInputCol() + "' back to " +
      "original string column '" + converter.getOutputCol() + "' using labels in metadata");
  converted.select("id", "categoryIndex", "originalCategory").show();

  // $example off$
  spark.stop();
}