public void foo(Integer... ids) {
Integer... fIds = bar(ids);
}
public void bar(Integer... ids) {
// I would like to eliminate few ids and return a subset. How should I declare the return argument
}
How should I declare the return type for bar?
You can refer to vararg parameters as an array.
public Integer[] bar(Integer... ids) {
..
}
See varargs docs
It is still true that multiple arguments must be passed in an array, but the varargs feature automates and hides the process
To the jvm this is actually an array, and the compiler has hidden the creation of the array.
Set bar's return type to Integer[] and in foo specify fIds type as Integer[] too.
Variable arguments parameters are just syntactic sugar for arrays, so you can just handle ids as an array of Integer (i.e. an Integer[]).
Something like that:
public Integer[] bar(Integer... ids) {
List<Integer> res = new ArrayList<Integer>();
for (Integer id : ids)
if (shouldBeIncluded(id)) res.add(id);
return res.toArray();
}
Integer... fIds = bar(ids);is legal.