Create a simple counter in java 11, using java IntSupplier - Then test it using IntStream

We will create a simple counter in java.

It will have a default initialization of 0.
It will have a constructor, which can be used to set the seed value of this counter.
It will implement Iterator interface
It will implement IntSupplier interface

package com.refactored.util;

import java.util.Iterator;
import java.util.function.IntSupplier;

public class Counter implements Iterator<Integer>, IntSupplier {

    private int count = 0;

    public Counter(){}

    public Counter(int seed) {
        count =  seed;
    }

    @Override
    public Integer next() {
        return ++count;
    }

    @Override
    public boolean hasNext(){
        return  count < Integer.MAX_VALUE;
    }

    @Override
    public int getAsInt() {
        return next().intValue();
    }
}

private int count = 0; this is our variable which stores the count. And it is initialized with 0. public Counter(){} this is our default constructor. This is the second constructor, which initializes the counter with the given value.

public Counter(int seed) {
  count =  seed;
}

Now, We are going to create a class to use this counter with it's default value.

package com.refactored.util;

import java.util.function.IntPredicate;
import java.util.stream.IntStream;

public class UseCounter {
    public static void main(String[] args) {
        Counter counter = new Counter();

        //Print the 10 elements
        IntPredicate limit_10 = limitStream(10);

        IntStream.generate(counter)
                .takeWhile(limit_10)
                .forEach(System.out::println);
    }

    private static IntPredicate limitStream(int lastCount) {
        return (int value) -> (value <= lastCount);
    }
}

After running this, we get the following output.

Now, we will create a counter with seed value of 100, and print from 101 to 110. Modified portion of code looks like this.

int seed = 100;
Counter counter = new Counter(seed);

//Print the 10 elements
IntPredicate limit_10 = limitStream(seed+10);

Let us, run this.

So, We have successfully created a counter. :) Happy coding.