How to convert java stream to scala streams?

Question

I am new to scala I am trying to understand the streams. Can I some tell me the difference between java 8 streams filter and streams in scala ?

How do I convert this in scala ?

For example if I want to convert this to scala do I need to use to Stream or Stream[] ?

itemList.getIds() is Map<String, List<Ids>>:

itemList.getIds().entrySet()
                    .stream()
                    .filter(entry -> validate(entry.getValue(), time))
                    .map(Map.Entry::getKey)
                    .findFirst().get()

Thanks

I don't believe itemList.getIds() is a list. More likely a Map. You don't need the scala stream class for this. In scala all the functional operations like filter, map are on every collection including Map. — Lionel Port, Sep 22 '16 at 22:31
@LionelPort Yeah I am sorry, it is a map. So I can straight way use filter ? — Newbie, Sep 22 '16 at 23:40

score 0 · Accepted Answer · answered Sep 23 '16 at 01:31

0

Here is a similar sample

Assuming a data structure and validate function is defined

val myMap = Map(1 -> "Value1",2 -> "Value2")
val time = System.currentTimeMillis

def validate(str:String, time:Long) = true

Then a straight translate of your code could simply be

myMap.filter(entry => validate(entry._2, time)).map(_._1).take(1)

answered Sep 23 '16 at 01:31

Lionel Port

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Im getting cannot resolve symbol filter, do I need to import anything ? – Newbie Sep 23 '16 at 23:14
I believe it is because the map is from a JAVA mojo class. – Newbie Sep 23 '16 at 23:25

How to convert java stream to scala streams?

1 Answers1