README.md
1# fbjni
2
3The Facebook JNI helpers library is designed to simplify usage of the
4[Java Native Interface](https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/jniTOC.html).
5The helpers were implemented to ease the integration of cross-platform mobile
6code on Android, but there are no Android specifics in the design. It can be
7used with any Java VM that supports JNI.
8
9```cpp
10struct JMyClass : JavaClass<JMyClass> {
11 static constexpr auto kJavaDescriptor = "Lcom/example/MyClass;";
12
13 // Automatic inference of Java method descriptors.
14 static std::string concatenate(
15 alias_ref<JClass> clazz,
16 // Automatic conversion to std::string.
17 std::string prefix) {
18 // Call methods easily.
19 static const auto getSuffix = clazz->getStaticMethod<JString()>("getSuffix");
20 // Manage JNI references automatically.
21 local_ref<JString> jstr = getSuffix(clazz);
22 // Automatic exception translation between Java and C++ (both ways).
23 // No need to check exception state after each call.
24 result += jstr->toStdString();
25 // Automatic conversion from std::string.
26 return result;
27 }
28};
29```
30
31## Documentation
32
33- [Why use a JNI wrapper?](docs/rationale.md)
34- [Set up your Android build with fbjni](docs/android_setup.md)
35- [Quick reference to most features (great for copy/pasting!)](docs/quickref.md)
36- [Internal documentation for maintainers](docs/maintainers.md)
37<!-- TODO: tutorial -->
38<!-- TODO: Comparison with other frameworks. -->
39
40## License
41
42fbjni is Apache-2 licensed, as found in the [LICENSE](/LICENSE) file.
43