onnxruntime/java/src/main/native/ai_onnxruntime_OnnxRuntime.c

/*
 * Copyright (c) 2019, 2020 Oracle and/or its affiliates. All rights reserved.
 * Licensed under the MIT License.
 */
#include <jni.h>
#include "onnxruntime/core/session/onnxruntime_c_api.h"
#include "ai_onnxruntime_OnnxRuntime.h"
#include "OrtJniUtil.h"

/*
 * Class:     ai_onnxruntime_OnnxRuntime
 * Method:    initialiseAPIBase
 * Signature: (I)J
 */
JNIEXPORT jlong JNICALL Java_ai_onnxruntime_OnnxRuntime_initialiseAPIBase
  (JNIEnv * jniEnv, jclass clazz, jint apiVersion) {
    (void) jniEnv; (void) clazz; // required JNI parameters not needed by functions which don't call back into Java.
    const OrtApi* ortPtr = OrtGetApiBase()->GetApi((uint32_t) apiVersion);
    return (jlong) ortPtr;
}

/*
 * Class:     ai_onnxruntime_OnnxRuntime
 * Method:    getAvailableProviders
 * Signature: (J)[Ljava/lang/String;
 */
JNIEXPORT jobjectArray JNICALL Java_ai_onnxruntime_OnnxRuntime_getAvailableProviders
    (JNIEnv * jniEnv, jclass clazz, jlong apiHandle) {
  (void) jniEnv; (void) clazz; // required JNI parameters not needed by functions which don't call back into Java.
  const OrtApi* api = (const OrtApi*) apiHandle;

  char** providers = NULL;
  int numProviders = 0;

  // Extract the provider array
  checkOrtStatus(jniEnv,api,api->GetAvailableProviders(&providers,&numProviders));

  // Convert to Java String Array
  char *stringClassName = "java/lang/String";
  jclass stringClazz = (*jniEnv)->FindClass(jniEnv, stringClassName);
  jobjectArray providerArray = (*jniEnv)->NewObjectArray(jniEnv,numProviders,stringClazz,NULL);

  for (int i = 0; i < numProviders; i++) {
    // Read out the provider name and convert it to a java.lang.String
    jstring provider = (*jniEnv)->NewStringUTF(jniEnv,providers[i]);
    (*jniEnv)->SetObjectArrayElement(jniEnv, providerArray, i, provider);
  }

  // Release providers
  checkOrtStatus(jniEnv,api,api->ReleaseAvailableProviders(providers,numProviders));
  providers = NULL;

  return providerArray;
}