Hi Uwe,
> Am 11.05.2016 um 21:35 schrieb Uwe Schindler <[email protected]>:
> With Java 9 this gets a bit worse: There is no "easy way" with the
> MethodHanldes class to generate a MethodHandles.countedLoop() on all elements
> of an array:
>
> public static MethodHandle countedLoop(MethodHandle iterations, MethodHandle
> init, MethodHandle body) [new in Java 9]
this isn't a remedy when you need the index in each iteration, but you can
generate a loop over all elements of an array using iteratedLoop(), as
illustrated by this test from LoopCombinatorTest:
@Test
public static void testIterateSum() throws Throwable {
// Integer[] a = new Integer[]{1,2,3,4,5,6}; int sum = 0; for (int e : a) {
sum += e; } return sum; => 21
MethodHandle loop = MethodHandles.iteratedLoop(Iterate.MH_sumIterator,
Iterate.MH_sumInit, Iterate.MH_sumStep);
assertEquals(Iterate.MT_sum, loop.type());
assertEquals(21, loop.invoke(new Integer[]{1, 2, 3, 4, 5, 6}));
}
... where MH_sumIterator is a handle to this method:
static Iterator<Integer> sumIterator(Integer[] a) {
return Arrays.asList(a).iterator();
}
Best,
Michael
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