https://github.com/hoehermann/typedjni

Wrap variardic JNI method calls into type-safe lambdas.
https://github.com/hoehermann/typedjni

java jni jni-wrapper

Last synced: 10 months ago
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Wrap variardic JNI method calls into type-safe lambdas.

• Host: GitHub
• URL: https://github.com/hoehermann/typedjni
• Owner: hoehermann
• License: mit
• Created: 2020-10-11T08:45:06.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2021-01-23T21:15:12.000Z (almost 5 years ago)
• Last Synced: 2024-10-12T10:10:23.279Z (over 1 year ago)
• Topics: java, jni, jni-wrapper
• Language: C++
• Homepage:
• Size: 33.2 KB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# TypedJNI

This module wraps the variardic JNI functions using C++ templates for offering type-safe and compact alternative.

Instead of the lengthy and error-prone

    jclass jcls = (*env)->FindClass(env, "SomeClass");

    if (jcls == NULL) {

        return; // handle error

    }

    jmethodID constructor = (*env)->GetMethodID(env, jcls, "", "(JLjava/lang/String;)V");

    if (constructor == NULL) {

        return; // handle error

    }

    jstring jsomestring = (*env)->NewStringUTF(env, somestring);

    if (jsomestring == NULL) {

        return; // handle error

    }

    jlong jsomelong = somelong; // explicitly convert

    jobject jobj = (*env)->NewObject(env, jcls, constructor, jsomelong, jsomestring);

    if (jobj == NULL) {

        return; // handle error

    }

    jmethodID method = (*env)->GetMethodID(env, jcls, "someMethod", "()V");

    if (method == NULL) {

        return; // handle error

    }

    (*env)->CallVoidMethod(env, jobj, method);

    (*env)->DeleteLocalRef(jsomestring); // late cleanup

    (*env)->DeleteLocalRef(jobj);

    

you can now write

    try {

       tenv.find_class("SomeClass").

            GetConstructor()(

                some_number, // implicit conversion where possible

                tenv.make_jstring(some_string) // explicit conversion with automated clean-up

            ).

            GetMethod("someMethod")();

    } catch (std::exception & e) {

        // handle error

    }

    

.