public class ListPerformance
{
 private static final int REPS = 100;
 private abstract static class Tester//内部抽象类，作为List测试。
 {
  String name;
  int size;
  Tester(String name, int size)
  {
   this.name = name;
   this.size = size;
  }
  abstract void test(List a);
 }
 private static Tester[] tests = {new Tester("get", 300)//一个测试数组，存储get(随机取)、iteration(顺序遍历)、insert(中间插入)、remove(随机删除)
 {
  void test(List a)
  {
   for (int i = 0; i < REPS; i++) {
    for (int j = 0; j < a.size(); j++) {
     a.get(j);
    }
   }
  }
 }, new Tester("iteration", 300)
 {
  void test(List a)
  {
   for (int i = 0; i < REPS; i++) {
    Iterator it = a.iterator();
    while (it.hasNext()) it.next();
   }
  }
 }, new Tester("insert", 1000)
 {
  void test(List a)
  {
   int half = a.size() / 2;
   String s = "test";
   ListIterator it = a.listIterator(half);
   for (int i = 0; i < size * 10; i++) {
    it.add(s);
   }
  }
 }, new Tester("remove", 5000)
 {
  void test(List a)
  {
   ListIterator it = a.listIterator(3);
   while (it.hasNext()) {
    it.next();
    it.remove();
   }
  }
 },
          };
 public static void test(List a)
 {
  System.out.println("Testing " + a.getClass().getName());//输出测试的类名称
  for (int i = 0; i < tests.length; i++) {
   fill(a, tests[i].size);//填充空集合
   System.out.print(tests[i].name);
   long t1 = System.currentTimeMillis();
   tests[i].test(a);//进行测试
   long t2 = System.currentTimeMillis();
   System.out.print(":" + (t2 - t1)+" ms ");
  }
 }
 public static Collection fill(Collection c, int size)
 {
  for (int i = 0; i < size; i++) {
   c.add(Integer.toString(i));
  }
  return c;
 }
 public static void main(String[] args)
 {
  test(new ArrayList());
  System.out.println();
  test(new LinkedList());
 }
}