Method create_instance

rust/src/api/mod.rs:444–519

Creates an `Instance` of the class `class_name`, passing an array of `InvocationArg`s to construct the instance.

(
        &self,
        class_name: &str,
        inv_args: &[impl Borrow<InvocationArg>],
    )

    /// Creates an `Instance` of the class `class_name`, passing an array of `InvocationArg`s to construct the instance.
    pub fn create_instance(
        &self,
        class_name: &str,
        inv_args: &[impl Borrow<InvocationArg>],
    ) -> errors::Result<Instance> {
        debug(&format!(
            "Instantiating class {} using {} arguments",
            class_name,
            inv_args.len()
        ));
        unsafe {
            // Factory invocation - first argument: create a jstring to pass as argument for the class_name
            let class_name_jstring: jstring =
                jni_utils::global_jobject_from_str(class_name, self.jni_env)?;

            // Factory invocation - rest of the arguments: Create a new objectarray of class InvocationArg
            let size = inv_args.len() as i32;
            let array_ptr = {
                let j = (opt_to_res(cache::get_jni_new_object_array())?)(
                    self.jni_env,
                    size,
                    cache::get_invocation_arg_class()?,
                    ptr::null_mut(),
                );
                jni_utils::create_global_ref_from_local_ref(j, self.jni_env)?
            };
            let mut inv_arg_jobjects: Vec<jobject> = Vec::with_capacity(size as usize);

            // Factory invocation - rest of the arguments: populate the array
            for i in 0..size {
                // Create an InvocationArg Java Object
                let inv_arg_java = inv_args[i as usize]
                    .borrow()
                    .as_java_ptr_with_global_ref(self.jni_env)?;
                // Set it in the array
                (opt_to_res(cache::get_jni_set_object_array_element())?)(
                    self.jni_env,
                    array_ptr,
                    i,
                    inv_arg_java,
                );
                inv_arg_jobjects.push(inv_arg_java);
            }
            // Call the method of the factory that instantiates a new class of `class_name`.
            // This returns a Instance that acts like a proxy to the Java world.
            let java_instance = (opt_to_res(cache::get_jni_call_static_object_method())?)(
                self.jni_env,
                cache::get_factory_class()?,
                cache::get_factory_instantiate_method()?,
                class_name_jstring,
                array_ptr,
            );

            // Check for exceptions before creating the globalref
            Self::do_return(self.jni_env, ())?;

            let java_instance_global_instance =
                jni_utils::create_global_ref_from_local_ref(java_instance, self.jni_env)?;