core/src/main/scala/io/prediction/controller/PPreparator.scala

/** Copyright 2015 TappingStone, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

package io.prediction.controller

import io.prediction.core.BasePreparator
import org.apache.spark.SparkContext

/** Base class of a parallel preparator.
  *
  * A parallel preparator can be run in parallel on a cluster and produces a
  * prepared data that is distributed across a cluster.
  *
  * @tparam TD Training data class.
  * @tparam PD Prepared data class.
  * @group Preparator
  */
abstract class PPreparator[TD, PD]
  extends BasePreparator[TD, PD] {

  private[prediction]
  def prepareBase(sc: SparkContext, td: TD): PD = {
    prepare(sc, td)
  }

  /** Implement this method to produce prepared data that is ready for model
    * training.
    *
    * @param sc An Apache Spark context.
    * @param trainingData Training data to be prepared.
    */
  def prepare(sc: SparkContext, trainingData: TD): PD
}