com.johnsnowlabs.nlp.ParamsAndFeaturesReadable.scala Maven / Gradle / Ivy

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/*
 * Copyright 2017-2022 John Snow Labs
 *
 * 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 com.johnsnowlabs.nlp

import org.apache.spark.ml.util.{DefaultParamsReadable, MLReader}
import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ArrayBuffer

class FeaturesReader[T <: HasFeatures](
    baseReader: MLReader[T],
    onRead: (T, String, SparkSession) => Unit)
    extends MLReader[T] {

  override def load(path: String): T = {

    val instance = baseReader.load(path)

    for (feature <- instance.features) {
      val value = feature.deserialize(sparkSession, path, feature.name)
      feature.setValue(value)
    }

    onRead(instance, path, sparkSession)

    instance
  }
}

trait ParamsAndFeaturesReadable[T <: HasFeatures] extends DefaultParamsReadable[T] {

  private val readers = ArrayBuffer.empty[(T, String, SparkSession) => Unit]

  private def onRead(instance: T, path: String, session: SparkSession): Unit = {
    for (reader <- readers) {
      reader(instance, path, session)
    }
  }

  def addReader(reader: (T, String, SparkSession) => Unit): Unit = {
    readers.append(reader)
  }

  override def read: MLReader[T] =
    new FeaturesReader(
      super.read,
      (instance: T, path: String, spark: SparkSession) => onRead(instance, path, spark))
}