package stream.basic;

import lambda.lambda5.mystream.MyStreamV3;

import java.util.List;
import java.util.stream.Stream;

public class LazyEvalMain3 {
    public static void main(String[] args) {
        List<Integer> data = List.of(1, 2, 3, 4, 5, 6);
        ex1(data);
        System.out.println();
        ex2(data);

    }

    private static void ex1(List<Integer> data) {
        System.out.println("== MyStreamV3 시작");
        Integer result = MyStreamV3.of(data)
                .filter(i -> {
                    boolean isEven = i % 2== 0;
                    System.out.println("filter() 실행: " + i + "(" + isEven + ")");
                    return isEven;
                })
                .map(i -> {
                    int mapped = i * 10;
                    System.out.println("map() 실행: " + i + " -> " + mapped);
                    return mapped;
                })
                .getFirst();

        System.out.println("result = " + result);
        System.out.println("== MyStreamV3 종료");
    }

    private static void ex2(List<Integer> data) {
        System.out.println("=== Stream API 시작 ===");
        Integer resut = data.stream()
                .filter(i -> {
                    boolean isEven = i % 2== 0;
                    System.out.println("filter() 실행: " + i + "(" + isEven + ")");
                    return isEven;
                })
                .map(i -> {
                    int mapped = i * 10;
                    System.out.println("map() 실행: " + i + " -> " + mapped);
                    return mapped;
                })
                .findFirst().get();
        System.out.println("resut = " + resut);
        System.out.println("=== Stream API 종료 ===");
    }
}