Wsrtjtyk

I'm trying to create a fibonacci sequence through the usage of Java Streams API. I've create a supplier, but I want it to stop at a specific value (e.g 1000000).

The suplier:

import java.util.function.Supplier;



public class FibonacciSupplier implements Supplier<Integer> {



    private int current;

    private int next;



    public FibonacciSupplier() {

        current = 0;

        next = 1;

    }



    @Override

    public Integer get() {

        int result = current;

        current = next + current;

        next = result;

        return result;

    }

}

How I would like it to be:

Stream.generate(new FibonacciSupplier()).maxValue(1000000);

The maxValue does not exist as a function, I'm using it as a name to for context.

The best solution is to use takeWhile, which is available in Java 9+:

Stream.generate(new FibonacciSupplier())

    .takeWhile(i -> i <= 1000000) //will stop stream when value exceeds given limit

    .forEach(System.out::println);

If you're using Java 8, then you may want to look into hacks for stopping an infinite stream

You'll need to use the .limit() method on the stream as below :

Stream.generate(new FibonacciSupplier()).limit(1000).forEach(System.out::println);

From the docs,

Returns a stream consisting of the elements of this stream, truncated
to be no longer than {@code maxSize} in length.