Native method signatures

[haelix888]

2 questions:
(1) You say "The type of the first parameter of the lambda must be jni::JNIEnv&. The type of the second parameter must be either jni::jclass*". Yet, in your Calculator example there in only the Env: "jni::jlong Add(jni::JNIEnv&, jni::jlong a, jni::jlong b)". Why?
(2) Why would you require the native class to take these 1 or 2 extra parameters? Isn't the purpose of your lib to present an already-defined class in a form consumable from Java?

[this-kirke]

1. The Calculator example is an example of Native Peer. Native peers are of type jni::Object<jni::Class<TagType>> meaning their accompanying Java classpath is exposed by the public static Name() method. The Java class must have a long peer; field, which jni.hpp uses to store the address of the Native instance. Now for, any methods that are registered to this peer pair, the jni::Class is already known which obviates the jclass parameter used in the low-level API or standard jni methods. Jni.hpp just absorbs that parameter in this case because it's not useful.

2. The Java method signature is long add(long a, long b) ..the jlong return type and parameters correspond to the Java-side return type and parameters.The native class method requires only one additional parameter, of type jni::JNIEnv&. It's not really an extra parameter as all standard jni calls have the JNIEnv* parameter. I assume it's included because nearly all jni.hpp API methods take a jni::JNIEnv& parameter and this way you're not required to cache it.