package com;

import java.util.function.BiFunction;

import java.util.function.Function;

public class DemoFunction {

    public static void main(String[] args) {

        DemoFunction t1 = new DemoFunction();

        // Function函数的使用

        Integer addResult = t1.compute(3, value -> value + value);

        System.out.println("加法结果：" + addResult);

        Integer subResult = t1.compute(3, value -> value - 1);

        System.out.println("减法结果：" + subResult);

        Integer multipResult = t1.compute(3, value -> value * value);

        System.out.println("乘法结果：" + multipResult);

        Integer divisionResult = t1.compute(6, value -> value / 3);

        System.out.println("除法结果：" + divisionResult);

        // 使用compose场景, 从右向左处理, 这里就是 (6 * 6) + 10 = 46

        Integer composeResult = t1.computeForCompose(6,

                value -> value + 10,

                value -> value * value);

        System.out.println("Function compose 结果：" + composeResult);

        // 使用andThen场景, 从左向右处理, 这里就是(3 + 20) - 10 = 13

        Integer andThenResult = t1.computeForAndThen(3,

                value -> value + 20,

                value -> value - 10);

        System.out.println("Function andThen 结果：" + andThenResult);

        // 使用 BiFunctioin场景, 这里是 2 + 3 = 5

        Integer biFuncResult = t1.computeForBiFunction(2, 3,

                (v1, v2) -> v1 + v2);

        System.out.println("BiFunction 结果：" + biFuncResult);

        // 使用 BiFunctioin andThen场景, 这里是 (2 * 3) + 6 = 12

        Integer biFuncAndThenResult = t1.computeForBiFunctionAndThen(2, 3,

                (v1, v2) -> v1 * v2, v1 -> v1 + 6);

        System.out.println("BiFunction andThen 结果：" + biFuncAndThenResult);

    }

    /**

     * @param num

     * @param function

     * @return

     * @desc 使用JDK8 Function函数

     */

    private Integer compute(Integer num, Function<Integer, Integer> function) {

        Integer result = function.apply(num);

        return result;

    }

    /**

     * @param num

     * @param function1

     * @param function2

     * @return

     * @desc 使用compose函数，简单的说，就是从右向左处理。

     */

    private Integer computeForCompose(Integer num,

            Function<Integer, Integer> function1,

            Function<Integer, Integer> function2) {

        return function1.compose(function2).apply(num);

    }

    /**

     * @param num

     * @param function1

     * @param function2

     * @return

     * @desc 使用andThen函数，简单的说，就是从左向右处理。

     */

    private Integer computeForAndThen(Integer num,

            Function<Integer, Integer> function1,

            Function<Integer, Integer> function2) {

        return function1.andThen(function2).apply(num);

    }

    /**

     * @param num1

     * @param nuum2

     * @param biFunction

     * @return

     * @desc 使用BiFunction

     */

    private Integer computeForBiFunction(Integer num1, Integer num2,

            BiFunction<Integer, Integer, Integer> biFunction) {

        return biFunction.apply(num1, num2);

    }

    /**

     * @param num1

     * @param num2

     * @param biFunction

     * @param function

     * @return

     * @desc 使用BiFunction andThen方法

     */

    private Integer computeForBiFunctionAndThen(Integer num1, Integer num2,

            BiFunction<Integer, Integer, Integer> biFunction,

            Function<Integer, Integer> function) {

        return biFunction.andThen(function).apply(num1, num2);

    }

}