InnerFunctionInterface.java

package com.winterbe.java8.samples.lambda;

/**
 * @author Benjamin Winterberg
 * @Message 1、内部FunctionInterface用法，实现与调用分离；2、lamdba内部可以操作类成员变量
 */
public class InnerFunctionInterface {

    private static int outerStaticNum;

    private int outerNum;

    void testScopes() {
        int num = 1;
        FunctionInterface.Converter<Integer, String> stringConverter = (from) -> String.valueOf(from + num);

        String convert = stringConverter.convert(2);
        System.out.println(convert); // 3

        FunctionInterface.Converter<Integer, String> stringConverter2 = (from) -> {
            outerNum = 13;
            return String.valueOf(from);
        };

        stringConverter2.convert(23);
        System.out.println(outerNum);// 13

        String[] array = new String[1];
        FunctionInterface.Converter<Integer, String> stringConverter3 = (from) -> {
            array[0] = "Hi there";
            return String.valueOf(from);
        };

        stringConverter3.convert(23);
        System.out.println(array[0]);// Hi there
    }

    public static void main(String[] args) {
        new InnerFunctionInterface().testScopes();
    }

}