Scala vs Java programming language

[rb76jaty]

In Excercise 4, we have to use .flatMap or .filter to simplify the given code. However, the syntax used in the solution is very different from the one observed on the slides and I'm having trouble understanding which syntax I should focus on. This also makes it difficult to digest the contents learned in class.
How would the following code be written using the syntax on the slides (Lecture ?

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(IO.read("filename.json")
  flatMap JSON.parse
  filter { !_.hasProperty(Ignore) }
  map someComplexComputation
  onComplete {
    case Success(result) =>
      println(s"final result: $result")
    case Failure(_) =>
      println("could not compute result")
   }
)

[JLP]

The code should be syntactically similar to what was shown in the lecture; except maybe for the infix notation of some combinators. The same code using dots and brackets looks like the following:

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(IO.read("filename.json")
  .flatMap(JSON.parse)
  .filter { !_.hasProperty(Ignore) }
  .map(someComplexComputation)
  .onComplete {
    case Success(result) =>
      println(s"final result: $result")
    case Failure(_) =>
      println("could not compute result")
   }
 )

[Malou]

Hey,

I was wondering if following code could work as well... Since this is the structure seen in the lecture:

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val content = IO.read("testEx04.json")
val processed = content.flatMap { content =>
    val json = JSON.parse(content)
    json.map { json =>
            val result = Future {
                someComplexComputation(json.filter{ !json.hasProperty(Ignore) }
            }
            result.map { result =>
                println(s"final result: $result")
            }
    }
}
processed.onComplete {
    case Failure(_) => 
        println("could not compute result")
}

I hope I'm not too late to have an answer before the exam

Thank's in advance

Malou

[salvaneschi]

" was wondering if following code could work as well... "

Did you try to run it?

[Malou]

Did you try to run it?

Yes, but I couldn't run it because IO.read and JSON.parse are methods of an external library (not mentioned in the exercise). Maybe akka?

Anyway, I'm pretty sure that it would work (since I've done some other tests) except for the filter part:

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someComplexComputation(json.filter{ !json.hasProperty(Ignore) }

So the proposed solution is a better option in this case I think.

Malou