The classify UDF example

KNNClassify.java

public String classify(double sepal_length, Double sepal_width, double petal_length, Double petal_width) {
    if (knnc == null) {
        throw new RuntimeException("Please run the IrisKNNClassifier procedure first to train the model.");
    }
    // Assemble the attributes together.
    DenseInstance dataRow = new DenseInstance(attributeCount);
    dataRow.put(0, sepal_length);
    dataRow.put(1, sepal_width);
    dataRow.put(2, petal_length);
    dataRow.put(3, petal_width);
    Object predictedClassValue = knnc.classify(dataRow);
    return (String) predictedClassValue;
}