NRBPerdijk

package tika.example

import java.io.ByteArrayOutputStream
import java.nio.charset.Charset

import org.apache.tika.metadata.Metadata
import org.apache.tika.sax.BodyContentHandler

import scala.util.{Failure, Success, Using}

NRBPerdijk

package tika.example

import java.io.InputStream

import org.apache.tika.config.TikaConfig
import org.apache.tika.metadata.Metadata
import org.apache.tika.parser.ocr.TesseractOCRConfig
import org.apache.tika.parser.pdf.PDFParserConfig
import org.apache.tika.parser.{AutoDetectParser, ParseContext, Parser}
import org.apache.tika.sax.BodyContentHandler

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    <dependency>
      <groupId>org.apache.tika</groupId>
      <artifactId>tika-core</artifactId>
      <version>1.24</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tika</groupId>
      <artifactId>tika-parsers</artifactId>
      <version>1.24</version>
    </dependency>

NRBPerdijk

case class WeatherForecast(
  humidity: Percentage,
  windForecast: WindForecast,
  sunshine: Percentage,
  temperature: Temperature,
  chanceOfRain: ChanceOfRain
)
case class Temperature(degrees: Int, temperatureScale: String)
case class Percentage(percent: Double)
case class WindForecast(windSpeed: WindSpeed, direction: String)

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generateWeatherForecasts <- function(pathToMagicFile) {
  # We're bringing the function contained in the file at the given location into scope
  source(paste(pathToMagicFile))

  # This returns a dataframe, a way for R to store large quantities of data in an ordered
  # manner (kind of like a Database Table...)
  weatherForecast <- magicHappensHere()

  # We use the Scala Domain object provided through GraalVM bindings to get ourselves an
  # instance of the Scala wrapper containing a List of WeatherForecast

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// Remember to always put a call to R in a Try block, because
// R often resorts to throwing RuntimeExceptions.
  Try(rMagicWithBindings(path)) match {
    case Failure(f) => print(f)
    case Success(weatherForecastList) =>
      // We get back a WeatherForecastList, which is a wrapper for List[WeatherForecast].
      // Now we can work with the results WITHOUT any parsing:
      // simply take out the List and do your operations (here we print them one by one).
      weatherForecastList.asScalaList.foreach(forecast => println(forecast))
  }

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  // This function signature is a lot cleaner than the one that doesn't use bindings.
  // It is also completely Scala, meaning we do not have to do ANY parsing.
  val rMagicWithBindings: String => WeatherForecastList =
    context.eval(sourceWithBindings).as(classOf[String => WeatherForecastList])

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  // This source will use the provided Domain instance to create objects as they have been
  // defined in the Scala domain.
  val sourceWithBindings: Source = 
    Source
      .newBuilder("R", Main.getClass.getResource("fun_WithBindingsWeatherForecasts.R"))
      .build()

NRBPerdijk

 /*
  * Our Domain object functions as a factory for our domain-related classes.
  * It has methods that create new instances of these classes, which can then safely be used from another Context.
  */
class Domain {
  def weatherForecastList(): WeatherForecastList = WeatherForecastList(List())
  def percentage(percent: Int): Percentage = Percentage(percent: Double)
  def chanceOfRain(chance: Percentage): ChanceOfRain = ChanceOfRain(chance: Percentage)
 
  def temperature(degrees: Int, temperatureScale: String): Temperature =

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/*
   * Exposing bindings is an interesting way to share functionality between languages.
   * This command makes an instance of the Domain class available under the "Domain"
   * accessor.
   */
  context.getBindings("R").putMember("Domain", new Domain)