How to transform a for loop into stream loop

Question

How to transform this code into a stream loop:

for(long l = 1L; l <= 250000; l++) {
     v = value.add(BigInteger.valueOf(myMethod.getInt()));
}

I need to get the 'v' as a unique BigInteger value.

Answer 1

Fundamentally, it looks like your myMethod.getInt method is a generator. Therefore, the best way to do this, in my opinion, is to create an infinite stream from your generator.

IntStream.generate(myMethod::getInt)
    .mapToObj(BigInteger::valueOf)
    .limit(25000)
    .reduce(BigInteger.ZERO, BigInteger::add)

This is clearer because you don't have to specify a range - the range is not what you care about, the number of elements is (i.e. the size of the range). You also don't have to ignore the parameter when you're mapping.