// Gets an array containing the CPU times consumed by a set of threads
// (in nanoseconds).  Each element of the array is the CPU time for the
// thread ID specified in the corresponding entry in the given array
// of thread IDs; or -1 if the thread does not exist or has terminated.
// If user_sys_cpu_time = true, the sum of user level and system CPU time
// for the given thread is returned; otherwise, only user level CPU time
// is returned.

JVM_ENTRY(void, jmm_GetThreadCpuTimesWithKind(JNIEnv *env, jlongArray ids,
                                              jlongArray timeArray,
                                              jboolean user_sys_cpu_time))

  {- -------------------------------------------
  (1) もし, 配列であるべき引数(ids 及び timeArray)が NULL だった場合は, NullPointerException.
      ---------------------------------------- -}

      // Check if threads is null
      if (ids == NULL || timeArray == NULL) {
        THROW(vmSymbols::java_lang_NullPointerException());
      }

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      ResourceMark rm(THREAD);
      typeArrayOop ta = typeArrayOop(JNIHandles::resolve_non_null(ids));
      typeArrayHandle ids_ah(THREAD, ta);

      typeArrayOop tia = typeArrayOop(JNIHandles::resolve_non_null(timeArray));
      typeArrayHandle timeArray_h(THREAD, tia);

  {- -------------------------------------------
  (1) 引数の配列(ids_ah)をチェックしておく.
      (もし不正な値であれば IllegalArgumentException)
      ---------------------------------------- -}

      // validate the thread id array
      validate_thread_id_array(ids_ah, CHECK);

  {- -------------------------------------------
  (1) もし, 引数で渡された配列(= 返値を入れるべき配列)の長さが
      スレッド数と異なっていれば, IllegalArgumentException.
      ---------------------------------------- -}

      // timeArray must be of the same length as the given array of thread IDs
      int num_threads = ids_ah->length();
      if (num_threads != timeArray_h->length()) {
        THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
                  "The length of the given long array does not match the length of "
                  "the given array of thread IDs");
      }

  {- -------------------------------------------
  (1) 引数で渡された配列(ids)中の各スレッドIDについて, 
      os::thread_cpu_time() で CPU 使用時間を取得し, 
      結果を格納する配列(timeArray)内に値を入れていく.
      ---------------------------------------- -}

      MutexLockerEx ml(Threads_lock);
      for (int i = 0; i < num_threads; i++) {
        JavaThread* java_thread = find_java_thread_from_id(ids_ah->long_at(i));
        if (java_thread != NULL) {
          timeArray_h->long_at_put(i, os::thread_cpu_time((Thread*)java_thread,
                                                          user_sys_cpu_time != 0));
        }
      }
    JVM_END