Some questions on 6312085: The for/in statement should support Iterators/Enumerations
sebastian.sickelmann at gmx.de
Sun Aug 28 13:25:42 PDT 2011
Hi, i thought about what todo to enable the enhanced-for-loop for
Iterators and Enumerations.
And it seems to me that the main problem is that the used
Iterator/Enumeration should not be used in other places( it should be
"private" for the loop).
As Iterable solves this through creating a new "private" Iterator for
the Iterable(ex. List/Set/....) it is not geranteed that there are
concurrent modifications on the Iterable. Typically the iterator solves
this through checking for concurrent modifications.
If i see it right it should be possible to use every
Iterator/Enumeration as a source for the enhanced-for-loop which is
Cloneable too. The main-problem I see is that it is not as easy to pin
out which Iterator / Enumeration i can put into the for-loop and which i
cannot. Additionaly i think that would lead into runtime-checks and not
compiletime-checks which would be really ugly. Let Iterator /
Enumeration extends Cloneable isn't a good solution because there will
be some Iterators/Enumerations that are not possible to clone.
Addtionaly there would be some compatibility issues, ex. let
Object.clone() do the job will not for every case) and there maybe more
compatibiliy issues(binary?) i don't see actually.
As i haven't found any source that brings in the Cloneable
Iterator/Enumeration solution into account with the enhanced-for-loop it
maybe a new idea.
Has some a good idea how to get to compiletime-checks with this solution
and/or how to transparently give the applicationdeveloper the feedback
he/she needs to intuitional use these?
Thanks for feedback.
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