text: /*
   * Author: Petre Eftime <petre.p.eftime@intel.com>
   * Copyright (c) 2016 Intel Corporation.
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
   * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
   * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  
  #pragma once
  #include <jni.h>
  #include <stdexcept>
  
  extern JavaVM* vm;
  
  
  /* 
   * This class provides a lifetime-managed JNIEnv object, which attaches or
   * detaches the current thread from the JVM automatically
   */
  class JNIEnvContainer {
  private:    
      JNIEnv *env = nullptr;
      
  public:
      /* Attaches this thread to the JVM if it is not already attached */
      JNIEnvContainer();
      /* Detaches this thread to the JVM if it is attached */
      ~JNIEnvContainer();
  
      /* Provides access to the local thread's JNIEnv object */
      JNIEnv *operator*();
      /* Provides access to the local thread's JNIEnv object's methods */
      JNIEnv *operator->();
  
      /* Attaches this thread to the JVM if it is not already attached */
      void attach();
      /* Detaches this thread to the JVM if it is attached */
      void detach();
  };
  
  /* Each thread has a local jni_env variable of JNIEnvContainer type */
  extern thread_local JNIEnvContainer jni_env;
  
  /*
   * This class provides a lifetime-managed GlobalRef variable, which is automatically
   * deleted when it goes out of scope.
   */
  class JNIGlobalRef {
  private:
      jobject object;
  
  public:
      /* Creates a GlobalRef from an object passed to it */
      JNIGlobalRef(jobject object);
      /* Deletes the stored GlobalRef */
      ~JNIGlobalRef();
  
      /* Provides access to the stored GlobalRef */
      jobject operator*();
  };
  
  