package com.brianway.learning.java8.streamapi;

import static java.util.Comparator.comparing;

import static java.util.stream.Collectors.toList;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

/**

* 指令式和函数式分别挑选低热量食物名

*/

public class StreamBasic {

public static void main(String... args) {

// Java 7

getLowCaloricDishesNamesInJava7(Dish.menu).forEach(System.out::println);

System.out.println("---");

// Java 8

getLowCaloricDishesNamesInJava8(Dish.menu).forEach(System.out::println);

}

/**

* 指令式

*/

public static List<String> getLowCaloricDishesNamesInJava7(List<Dish> dishes) {

List<Dish> lowCaloricDishes = new ArrayList<>();

for (Dish d : dishes) {

if (d.getCalories() < 400) {

lowCaloricDishes.add(d);

}

}

List<String> lowCaloricDishesName = new ArrayList<>();

Collections.sort(lowCaloricDishes, new Comparator<Dish>() {

public int compare(Dish d1, Dish d2) {

return Integer.compare(d1.getCalories(), d2.getCalories());

}

});

for (Dish d : lowCaloricDishes) {

lowCaloricDishesName.add(d.getName());

}

return lowCaloricDishesName;

}

/**

* 函数式

*/

public static List<String> getLowCaloricDishesNamesInJava8(List<Dish> dishes) {

return dishes.stream()

.filter(d -> d.getCalories() < 400)

.sorted(comparing(Dish::getCalories))

.map(Dish::getName)

.collect(toList());

}

}