// Support for java.lang.Thread.getStackTrace() and getAllStackTraces() methods
// Return StackTraceElement[][], each element is the stack trace of a thread in
// the corresponding entry in the given threads array

JVM_ENTRY(jobjectArray, JVM_DumpThreads(JNIEnv *env, jclass threadClass, jobjectArray threads))

  {- -------------------------------------------
  (1) (トレース出力) (See: JVMWrapper)
      ---------------------------------------- -}

      JVMWrapper("JVM_DumpThreads");

  {- -------------------------------------------
  (1) (プロファイル情報の記録) (See: JvmtiVMObjectAllocEventCollector)
      ---------------------------------------- -}

      JvmtiVMObjectAllocEventCollector oam;

  {- -------------------------------------------
  (1) もし引数(threads)が NULL であれば, NullPointerException.
      ---------------------------------------- -}

      // Check if threads is null
      if (threads == NULL) {
        THROW_(vmSymbols::java_lang_NullPointerException(), 0);
      }

  {- -------------------------------------------
  (1) もし引数(threads)の配列長が 0 であれば, IllegalArgumentException.
      ---------------------------------------- -}

      objArrayOop a = objArrayOop(JNIHandles::resolve_non_null(threads));
      objArrayHandle ah(THREAD, a);
      int num_threads = ah->length();
      // check if threads is non-empty array
      if (num_threads == 0) {
        THROW_(vmSymbols::java_lang_IllegalArgumentException(), 0);
      }

  {- -------------------------------------------
  (1) もし引数(threads)が java.lang.Thread の配列でなければ, IllegalArgumentException.
      ---------------------------------------- -}

      // check if threads is not an array of objects of Thread class
      klassOop k = objArrayKlass::cast(ah->klass())->element_klass();
      if (k != SystemDictionary::Thread_klass()) {
        THROW_(vmSymbols::java_lang_IllegalArgumentException(), 0);
      }

  {- -------------------------------------------
  (1) (ResourceMark)
      ---------------------------------------- -}

      ResourceMark rm(THREAD);

  {- -------------------------------------------
  (1) ThreadService::dump_stack_traces() には 
      GrowableArray として引数を渡す必要があるので, 
      引数の配列の中身を GrowableArray に詰め直す.
      ---------------------------------------- -}

      GrowableArray<instanceHandle>* thread_handle_array = new GrowableArray<instanceHandle>(num_threads);
      for (int i = 0; i < num_threads; i++) {
        oop thread_obj = ah->obj_at(i);
        instanceHandle h(THREAD, (instanceOop) thread_obj);
        thread_handle_array->append(h);
      }

  {- -------------------------------------------
  (1) ThreadService::dump_stack_traces() を呼んで
      スタックトレースを表す java.lang.StackTraceElement オブジェクト(の配列の配列)を取得し, 
      それを JNIHandle 化してリターンする.
      ---------------------------------------- -}

      Handle stacktraces = ThreadService::dump_stack_traces(thread_handle_array, num_threads, CHECK_NULL);
      return (jobjectArray)JNIHandles::make_local(env, stacktraces());

    JVM_END