Java 8: preferred way to count iterations of a lambda?

Question

I face the same problem often. I need to count the runs of a lambda for use outside the lambda.

E.g.:

myStream.stream().filter(...).forEa         


        

Answer 1

You shouldn't use AtomicInteger, you shouldn't use things unless you have a really good reason to use. And the reason for using AtomicInteger might be only allowing concurrent accesses or such as.

When it comes to your problem;

Holder can be use for holding and incrementing it inside a lambda. And after you can get it by calling runCount.value

Holder runCount = new Holder<>(0);

myStream.stream()
    .filter(...)
    .forEach(item -> { 
        foo();
        bar();
        runCount.value++; // now it's work fine!
    });
System.out.println("The lambda ran " + runCount + " times");