diff --git a/include/modules/jack.hpp b/include/modules/jack.hpp
index 2433a43e..71753985 100644
--- a/include/modules/jack.hpp
+++ b/include/modules/jack.hpp
@@ -15,16 +15,20 @@ class JACK : public ALabel {
   JACK(const std::string&, const Json::Value&);
   ~JACK() = default;
   auto update() -> void;
-  jack_nframes_t      bufsize_;
-  jack_client_t*      client_;
-  unsigned int        xruns_;
-  std::string         state_;
-  pthread_t           jack_thread_;
+
+  int                 bufSize(unsigned int size);
+  int                 xrun();
+  void                shutdown();
 
  private:
   std::string         JACKState();
 
+  jack_client_t*      client_;
+  jack_nframes_t      bufsize_;
   jack_nframes_t      samplerate_;
+  unsigned int        xruns_;
+  std::string         state_;
+  pthread_t           jack_thread_;
   util::SleeperThread thread_;
 };
 
diff --git a/src/modules/jack.cpp b/src/modules/jack.cpp
index fd183c7e..45dab230 100644
--- a/src/modules/jack.cpp
+++ b/src/modules/jack.cpp
@@ -105,23 +105,32 @@ auto waybar::modules::JACK::update() -> void {
   ALabel::update();
 }
 
-int bufSizeCallback(unsigned int size, void *obj) {
-  waybar::modules::JACK* x = (waybar::modules::JACK*)obj;
-  x->bufsize_ = size;
+int waybar::modules::JACK::bufSize(unsigned int size) {
+  bufsize_ = size;
   return size;
 }
 
-int xrunCallback(void *obj) {
-  waybar::modules::JACK* x = (waybar::modules::JACK*)obj;
-  x->xruns_ += 1;
-  x->state_ = "xrun";
+int waybar::modules::JACK::xrun() {
+  xruns_ += 1;
+  state_ = "xrun";
   return 0;
 }
 
-void shutdownCallback(void *obj) {
-  waybar::modules::JACK* x = (waybar::modules::JACK*)obj;
-  pthread_cancel(x->jack_thread_);
-  x->client_ = NULL;
-  x->state_ = "disconnected";
-  x->xruns_ = 0;
+void waybar::modules::JACK::shutdown() {
+  pthread_cancel(jack_thread_);
+  client_ = NULL;
+  state_ = "disconnected";
+  xruns_ = 0;
+}
+
+int bufSizeCallback(unsigned int size, void *obj) {
+  return static_cast<waybar::modules::JACK*>(obj)->bufSize(size);
+}
+
+int xrunCallback(void *obj) {
+  return static_cast<waybar::modules::JACK*>(obj)->xrun();
+}
+
+void shutdownCallback(void *obj) {
+  return static_cast<waybar::modules::JACK*>(obj)->shutdown();
 }