geraldcroes

object ObjectFileParserFactory : FileParserFactory {
    override fun createFromFileName(fileName: String) =
            when (fileName.substringAfterLast('.')) {
                "xml" -> XmlFileParser()
                "json" -> JsonFileParser()
                else -> throw Exception("I don't know how to deal with $fileName.")
            }
}

geraldcroes

class CompanionObjectFileParserFactory : FileParserFactory {
    companion object : FileParserFactory{
        override fun createFromFileName(fileName: String) =
                when (fileName.substringAfterLast('.')) {
                    "xml" -> XmlFileParser()
                    "json" -> JsonFileParser()
                    else -> throw Exception("I don't know how to deal with $fileName.")
                }
    }
    /* needed if you want to be able to call the createFromFileName from an instance */

geraldcroes

MyFileParserFactory.createFromFileName("filename.json")

geraldcroes

class CompanionObjectFileParserFactory {
    companion object : FileParserFactory{
        override fun createFromFileName(fileName: String) =
                when (fileName.substringAfterLast('.')) {
                    "xml" -> XmlFileParser()
                    "json" -> JsonFileParser()
                    else -> throw Exception("I don't know how to deal with $fileName.")
                }
    }
}

geraldcroes

val parserFactory = StandardFileParserFactory()
val fileParser = parserFactory.createFromFileName(“filename.xml”)

geraldcroes

/* The concept of the factory -> creates a Product */
interface FileParserFactory {
    fun createFromFileName(fileName: String): FileParser
}
 
/* Our specific Factory */
class StandardFileParserFactory : FileParserFactory {
    override fun createFromFileName(fileName: String) =
            when (fileName.substringAfterLast('.')) {
                "xml" -> XmlFileParser()

geraldcroes

class XmlFileParser : FileParser
class JsonFileParser : FileParser

geraldcroes

interface FileParser

geraldcroes

{
   "time": "9:30pm"
}

geraldcroes

{
  "client_id": "my-id",
  "date": "2018–12–12",
  "time": "9:00pm", 
  "number_of_guests": 2
}