MathUtil.java

package apijson.demo.server;

public class MathUtil {

	public static long plus(long a, long b) {
		return a + b;
	}
	public static double plus(double a, double b) {
		return a + b;
	}
	public static double plus(Number a, Number b) {
		return plus(a.doubleValue(), b.doubleValue());
	}

	public static long minus(long a, long b) {
		return a - b;
	}
	public static double minus(double a, double b) {
		return a - b;
	}
	public static double minus(Number a, Number b) {
		return minus(a.doubleValue(), b.doubleValue());
	}

	public static long multiply(long a, long b) {
		return a * b;
	}
	public static double multiply(double a, double b) {
		return a * b;
	}
	public static double multiply(Number a, Number b) {
		return multiply(a.doubleValue(), b.doubleValue());
	}

	public static double divide(long a, long b) {
		return divide((double) a, (double) b);  //直接相除会白自动强转为 long，1/2 = 0 !  a / b;
	}
	public static double divide(double a, double b) {
		return a / b;
	}
	public static double divide(Number a, Number b) {
		return divide(a.doubleValue(), b.doubleValue());
	}

	public static long pow(long a, long b) {
		return (long) Math.pow(a, b);
	}
	public static double pow(double a, double b) {
		return Math.pow(a, b);
	}
	public static double pow(Number a, Number b) {
		return pow(a.doubleValue(), b.doubleValue());
	}

	public static double sqrt(long a) {
		return Math.sqrt(a);
	}
	public static double sqrt(double a) {
		return Math.sqrt(a);
	}
	public static double sqrt(Number a) {
		return sqrt(a.doubleValue());
	}

	public static Long computeAsync(long a, long b, TestInterface callback) {
		callback.setData("Mock outer interface success!");
		Boolean sort = callback.sort();
		if (sort != null && sort && a > b) {
			callback.minusAsId(b, a);
		}
		else {
			callback.minusAsId(a, b);
		}
		return callback.getId();
	}

	public static Number computeAsync(long a, long b, Callback callback) {

		new Thread(new Runnable() {

			@Override
			public void run() {
				try {
					Thread.sleep(3000);
				} catch (Exception e) {}

				Boolean sort = callback.sort();
				if (sort != null && sort && a > b) {
					callback.minusAsId(b, a);
				} else {
					callback.minusAsId(a, b);
				}

				callback.setData("Mock inner interface success!");
			}
		}).start();

		return callback.getId();
	}


	public static <D> D computeAsync(long a, long b, D d, Callback1<D> callback) {
		callback.minusAsId(a, b);
		callback.setData(d);
		return callback.getData();
	}

	public static <L, D> Callback2<L, D> computeAsync(L a, L b, D d, Callback2<L, D> callback) {
		callback.setA(a);
		callback.setB(b);
		callback.setData(d);
		callback.append(a, b);
		return callback;
	}

	//需要用 $ 隔开内部类与它所在的类  apijson.demo.server.MathUtil$Callback
	public interface Callback2<L, D> {
		void setId(L id);
		L getId();

		void setData(D data);
		D getData();

		void setA(L a);
		L getA();

		void setB(L b);
		L getB();

		default String append(L a, L b) {
			return "a=" + a + "; b=" + b;
		}
	}

	public interface Callback1<D> extends Callback2<Long, D> {
		Boolean sort();

		default void minusAsId(long a, long b) {
			setA(a);
			setB(b);
			setId(a + b);
		}
	}

	public interface Callback extends Callback1<String> {
		static long currentTime() {
			return System.currentTimeMillis();
		}

		@Override
        default void minusAsId(long a, long b) {
            System.out.println("minusAsId  startTime: " + currentTime());
            setA(a);
            setB(b);
            setId(a + b);
            System.out.println("minusAsId  endTime: " + currentTime());
        }
	}

}