java函数式编程

星月IWJ2024-03-09 12:24

1,定义函数式接口

java 复制代码

package com.xingyuezhiyun.practice.lambada;

@FunctionalInterface
public interface PickerSelector<T extends Fruit> {

    boolean pick(T fruit);
}

2,提供处理函数并调用

java 复制代码

package com.xingyuezhiyun.practice.lambada;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Main {

public static void main(String [] args) {
        List<Fruit> fruitList = Arrays.asList(new Fruit("aaa", "red"){}, new Fruit("bbb", "blue"){});

        System.out.println(pickFruit(fruitList, new RedInstance()));
        System.out.println(pickFruit(fruitList, new BlueInstance()));
        System.out.println(pickFruit(fruitList, fruit -> fruit.getColor().equals("red")));

    }

public static List<Fruit> pickFruit(List<Fruit> fruitList, PickerSelector<Fruit> pickerSelector){
        List<Fruit> result = new ArrayList<>();
        fruitList.forEach(fruit -> {
            if (pickerSelector.pick(fruit)){
                result.add(fruit);
            }
        });
        
        return result;
    }
}

函数式接口函数描述符

java 复制代码

Predicate<T>	  (T)  -> boolean
Consumer<T>	  (T)  -> void
Function< T, R >	  (T)  -> R
Supplier<T>	  ( )  -> T
UnaryOperator<T> 	  (T)  ->  T 
BinaryOperator<T>	  (T, T) -> T
BiPredicate<L, R>	  (L, R)  -> boolean
BiConsumer<T, U>	  (T, U)  -> void
BiFunction<T, U, R>	  (T, U)  -> R