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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

// scalastyle:off println
package org.apache.spark.examples.ml

import scala.beans.BeanInfo

import org.apache.spark.{SparkConf, SparkContext}
import org.apache.spark.ml.Pipeline
import org.apache.spark.ml.classification.LogisticRegression
import org.apache.spark.ml.feature.{HashingTF, Tokenizer}
import org.apache.spark.mllib.linalg.Vector
import org.apache.spark.sql.{Row, SQLContext}

@BeanInfo
case class LabeledDocument(id: Long, text: String, label: Double)

@BeanInfo
case class Document(id: Long, text: String)

/**
 * A simple text classification pipeline that recognizes "spark" from input text. This is to show
 * how to create and configure an ML pipeline. Run with
 * {{{
 * bin/run-example ml.SimpleTextClassificationPipeline
 * }}}
 */
object SimpleTextClassificationPipeline {

  def main(args: Array[String]) {
    val conf = new SparkConf().setAppName("SimpleTextClassificationPipeline")
    val sc = new SparkContext(conf)
    val sqlContext = new SQLContext(sc)
    import sqlContext.implicits._

    // Prepare training documents, which are labeled.
    val training = sc.parallelize(Seq(
      LabeledDocument(0L, "a b c d e spark", 1.0),
      LabeledDocument(1L, "b d", 0.0),
      LabeledDocument(2L, "spark f g h", 1.0),
      LabeledDocument(3L, "hadoop mapreduce", 0.0)))

    // Configure an ML pipeline, which consists of three stages: tokenizer, hashingTF, and lr.
    val tokenizer = new Tokenizer()
      .setInputCol("text")
      .setOutputCol("words")
    val hashingTF = new HashingTF()
      .setNumFeatures(1000)
      .setInputCol(tokenizer.getOutputCol)
      .setOutputCol("features")
    val lr = new LogisticRegression()
      .setMaxIter(10)
      .setRegParam(0.001)
    val pipeline = new Pipeline()
      .setStages(Array(tokenizer, hashingTF, lr))

    // Fit the pipeline to training documents.
    val model = pipeline.fit(training.toDF())

    // Prepare test documents, which are unlabeled.
    val test = sc.parallelize(Seq(
      Document(4L, "spark i j k"),
      Document(5L, "l m n"),
      Document(6L, "spark hadoop spark"),
      Document(7L, "apache hadoop")))

    // Make predictions on test documents.
    model.transform(test.toDF())
      .select("id", "text", "probability", "prediction")
      .collect()
      .foreach { case Row(id: Long, text: String, prob: Vector, prediction: Double) =>
        println(s"($id, $text) --> prob=$prob, prediction=$prediction")
      }

    sc.stop()
  }
}
// scalastyle:on println