Create an IntStream and a Stream<Integer> from an Eclipse Collections IntList/IntIterable
Edit: Holger found a much clearer solution:
public static IntStream intListToIntStream(IntList intList) {
return IntStream.range(0, intList.size()).map(intList::get);
}
After looking into the IntIterator
code, it turns out the implementation is equivalent to this, so the below solutions are unnecessary. You can even make this more efficient using .parallel()
.
If you're on Java 9, you can use this method:
public static IntStream intListToIntStream(IntList intList) {
IntIterator intIter = intList.intIterator();
return IntStream.generate(() -> 0)
.takeWhile(i -> intIter.hasNext())
.map(i -> intIter.next());
}
Otherwise, I don't see a better solution than wrapping the IntIterator as a PrimitiveIterator.OfInt and building a stream out of that:
public static IntStream intListToIntStream(IntList intList) {
IntIterator intIter = intList.intIterator();
return StreamSupport.intStream(Spliterators.spliterator(new PrimitiveIterator.OfInt() {
@Override
public boolean hasNext() {
return intIter.hasNext();
}
@Override
public int nextInt() {
return intIter.next();
}
}, intList.size(), Spliterator.ORDERED), false);
}
Either way, you can just get a Stream<Integer>
by calling IntStream.boxed()
.
With Eclipse Collections 10.0 you can now call primitiveStream
directly on IntList
.
IntStream intStream = IntLists.mutable.with(1, 2, 3, 4, 5).primitiveStream();
Stream<Integer> stream = intStream.boxed();