Question

我正在使用BiFunction来发送函数。

我现在拥有的是：

public class Animal {
    public static String cat(
        final String field,
        final Object value
    ) {
        return "(CAT:" + field + toString(value) + ")";
    }

    public static String dog(
        final String field,
        final Object value
    ) {
        return "(DOG:" + field + toString(value) + ")";
    }
}

public String getAnimal(
    final String animalFieldName,
    final BiFunction<String, Object, String> function,
    final Object animelieldValue
) {
    return function.apply(animalFieldName, animalFieldValue);
}

我这样用它：

new Animal("catName", Animal::cat, "catti")

我想要的是BiFunction＆lt;＆gt;将是一个枚举，所以getAnimal（）的签名将是：

String getAnimal(
    final String animalFieldName,
    /* Enum that has values that are BiFunctions, */
    final Object animalFieldValue
)

有什么建议吗？我会很感激代码示例。

Answer 1

不太确定你想要什么，但这似乎符合要求？

enum Animal implements BiFunction<String, Object, String> {
    CAT,
    DOG,
    BEAR {
        @Override
        public String apply(String s, Object o) {
            return "This is a Bear!!!";
        }
    };

    @Override
    public String apply(String s, Object o) {
        return "(" + name() + ":" + s + o.toString() + ")";
    }
}

public void test() {
    for (Animal animal : Animal.values()) {
        System.out.println(animal.apply("hello", "Hello"));
    }
}

Answer 2

@ OldCurmudgeon的答案的变体，有更多的lambdas：

enum Animal implements BiFunction<String, Object, String> {
    CAT,
    DOG,
    BEAR((s, o) -> "This is a Bear!!!");

    private final BiFunction<String, Object, String> function;

    private Animal(final BiFunction<String, Object, String> function) {
        this.function = function;
    }

    private Animal() {
        super((s, o) -> "(" + name() + ":" + s + o.toString() + ")");
    }
}

public void test() {
    Animal
        .values()
        .stream(animal -> animal.apply("hello", "Hello"))
        .forEach(System.out::println)
    ;
}

双功能＆LT;＆GT;与Enum

2 个答案: