SortCompare.time的反射版本

"Algorithms" by Robert Sedgewick, p256, SortCompare.time():

public static double time(String alg, Double[] a) throws SecurityException,
NoSuchMethodException, ClassNotFoundException,
IllegalArgumentException, IllegalAccessException,
InvocationTargetException {
Stopwatch timer = new Stopwatch();
String originClassName = new Object(){}.getClass().getEnclosingClass().getName();
String packageName = originClassName.substring(0,
originClassName.lastIndexOf("."));
String className = packageName.concat("." + alg);
Class<?> clazz = Class.forName(className);
Method sortMethod = clazz.getDeclaredMethod("sort", Comparable[].class);
Object[] param = { a };
sortMethod.invoke(null, param);
return timer.elapsedTime();
}

这里面注意的有两点，一是在static方法里获取所在类名的方法，二是如何用反射调用参数为数组的方法（见笔记 用反射机制在运行时创建对象并执行方法 ）。