examples/scala-parallel-classification/add-algorithm/src/main/scala/NaiveBayesAlgorithm.scala

package org.template.classification

import io.prediction.controller.P2LAlgorithm
import io.prediction.controller.Params

import org.apache.spark.SparkContext
import org.apache.spark.mllib.classification.NaiveBayes
import org.apache.spark.mllib.classification.NaiveBayesModel
import org.apache.spark.mllib.linalg.Vectors

case class NaiveBayesAlgorithmParams(
  lambda: Double
) extends Params

// extends P2LAlgorithm because the MLlib's NaiveBayesModel doesn't contain RDD.
class NaiveBayesAlgorithm(val ap: NaiveBayesAlgorithmParams)
  extends P2LAlgorithm[PreparedData, NaiveBayesModel, Query, PredictedResult] {

  def train(sc: SparkContext, data: PreparedData): NaiveBayesModel = {
    NaiveBayes.train(data.labeledPoints, ap.lambda)
  }

  def predict(model: NaiveBayesModel, query: Query): PredictedResult = {
    val label = model.predict(Vectors.dense(query.features))
    new PredictedResult(label)
  }

}