Scala Factory Design Pattern,what is "loose" coupling? - scala

Question

I am studying about the Factory Design Pattern in Scala.One of the benefits of this method is Loose Coupling between Object Creation logic and Client (from http://www.journaldev.com/10350/factory-design-pattern-in-scala). How can we achieve this and why we need loose coupling at all? Can someone give some examples and explain this?

Answer 1

As I understood you are looking for an example on Factory Pattern in Scala, you can find the usecase with some simple examples here
Factory pattern is more useful when creating API library classes (classes which can be used by other classes). Hope the below example will explain it clearly,
trait ContentAPI {
def getContentById(id : Int) : String
def getContentByTitle(title: String) : String
def getAllContent(title: String) : String }
object ContentAPI {
protected class ContentAPI(config: APIConfig) extends PageContentAPI {
/**
* get all content of a page parsing the page title
*
* #param query title parsed
* #return all content as a String
*/
override def getAllContent(query: String) : String = {
var pageContent: String = " Some text"
pageContent
}
/**
* get only the content body text parsing the page title
*
* #param query title parsed
* #return content as a String
*/
override def getContentByTitle(query: String) : String = {
var pageContent: String = " Some String "
pageContent
}
/**
* get only the content body text parsing the page id
*
* #param query id parsed
* #return content as a string
*/
override def getContentById(query: Int) : String
var pageContent: String = "some string"
pageContent
}
}
class APIConfig(path: String) {
val inputPath = path
}
/** Configuration object for the Content API */
object APIConfig {
protected class APIConfigBuilder(dataPath: String) {
def setDataPath(path: String): APIConfigBuilder = {
new APIConfigBuilder(path)
}
def getOrCreate(): APIConfig = {
new APIConfig(dataPath)
}
}
def withBuilder(): APIConfigBuilder = {
new APIConfigBuilder("")
}
}
def apply(config: APIConfig): ContentAPI = {
new ContentAPI(config)
}
}
/** Client Object */
object APIClient{
def main(args: Array[String]): Unit = {
import Arguments.WIKI_DUMP_BASE
val dataPath = "path"
val contentAPI = ContentAPI(APIConfig.withBuilder().setDataPath(dataPath).getOrCreate())
contentAPI.getAllContent("Anarchism").show()
contentAPI.getContentByTitle("Anarchism").show()
contentAPI.getContentById(12).show()
}
}