Add delay between calls

FunctionalRetry.java

import java.util.function.Consumer;
import java.util.function.Supplier;

import io.vavr.Tuple;
import io.vavr.Tuple2;
import io.vavr.collection.Stream;
import io.vavr.control.Option;
import io.vavr.control.Try;

public class FunctionalRetry {

  public static <T> Option<T> of(int maxTries, Supplier<T> theWorker, Consumer<Tuple2<Integer, Try<T>>> watch) {
    return Stream.range(0, maxTries)
      .map(it -> Tuple.of(it, Try.ofSupplier(theWorker)))
      .peek(watch)
      .peek(t -> { if(t._2.isFailure()) try { Thread.sleep(1000); } catch(Exception e) {}; })
      .find(result -> result._2.isSuccess()).map(t -> t._2.get());
  }

  public static <T> Option<T> of(int maxTries, Supplier<T> theWorker) {
    return of(maxTries, theWorker, input -> System.out.println("Iteration:" + input._1 + "> Result:" + input._2));
  }

}

Main.java

import java.util.Random;
import io.vavr.control.Option;

public class Main {

  public static void main(String[] args) {
    Option<Integer> mayBe = FunctionalRetry.of(10, Main::doSomething);
    if (mayBe.isDefined()) System.out.println(mayBe.get());
  }

  //Sample test function
  public static int doSomething() {
    if (new Random().nextInt(5) != 0) throw new NumberFormatException();
    return 1;
  }
}