Help collections

[nikosv]

I have two arrayLists diferent types.....
ArrayList<Ergazomenos> erg=new ArrayList<Ergazomenos>();
ArrayList<Proistamenos> proist=new ArrayList<Proistamenos>();



copy(erg ,proist);
I dont know how to copy ergazomenos to proistamenos. Can i use arraycopy?

[eRaaaa]

what exactly do you mean with "copy" ?

ArrayList (Java Platform SE 6)

??

[nikosv]

I want to copy all elements from arrayList erg to arrayList proist.
thanks for the answear

[Tolls]

Does class Ergazomenos extend or implement Proistamenos?
If not then you can't (well, I suspect you could if you cheated, but you shouldn't).

[nikosv]

class Proistamenos extends Ergazomenos

[Tolls]

addAll() should work then.

[nikosv]

I cant use addall because erg is type of Ergazomenos and proist is type of Proistamenos

thanks anyway for your answer

[Tolls]

Yes you can.
Since Ergazomenos extends Proistamenos you can:

proist.addAll(erg);

Because addAll() allows Collection<? extends E>...which would be Collection<? extends Proistamenos>. Which you just said Ergazomenos does.

ETA: Oops. I misread your post.
It's the other way around!

In which case you have a design flaw.

[Tolls]

Um, you should start your own thread and not hijack someone else's.