java: Add initial support for Java notifications

Signed-off-by: Petre Eftime <[email protected]>

1 files changed, 65 insertions, 0 deletions

diff --git a/java/jni/JNIMem.hpp b/java/jni/JNIMem.hpp
new file mode 100644
index 0000000..3b20e05
--- /dev/null
+++ b/java/jni/JNIMem.hpp
@@ -0,0 +1,65 @@
+#pragma once
+#include <jni.h>
+#include <stdexcept>
+
+extern JavaVM* vm;
+
+class JNIEnvContainer {
+private:    
+    JNIEnv *env = nullptr;
+    
+public:
+    JNIEnv *operator*() {
+        attach();
+        return env;
+    }
+
+    JNIEnv *operator->() {
+        attach();
+        return env;
+    }
+
+    JNIEnvContainer() {
+    }
+
+    ~JNIEnvContainer() {
+        detach();
+    }
+
+    void attach() {
+        if (env != nullptr)
+            return;
+        jint err = vm->AttachCurrentThreadAsDaemon((void **)&env, NULL);
+        if (err != JNI_OK)
+            throw std::runtime_error("Attach to VM failed");
+    }
+
+    void detach() {
+        if (env == nullptr)
+            return;
+        vm->DetachCurrentThread();
+        env = nullptr;
+    }
+};
+
+extern thread_local JNIEnvContainer jni_env;
+
+class JNIGlobalRef {
+private:
+    jobject object;
+
+public:
+    
+    JNIGlobalRef(jobject object) {
+        this->object = jni_env->NewGlobalRef(object);
+    }
+
+    ~JNIGlobalRef() {
+        jni_env->DeleteGlobalRef(object);
+    }
+
+    jobject operator*() {
+        return object;
+    }
+};
+