pytorch native code cleanup

zoo/src/main/java/com/intel/analytics/zoo/pipeline/api/net/PytorchModelWrapper.java

@@ -0,0 +1,41 @@
+package com.intel.analytics.zoo.pipeline.api.net;
+
+import com.intel.analytics.zoo.pipeline.inference.JTensor;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.InputStream;
+import java.net.URL;
+import java.nio.channels.FileChannel;
+import java.nio.channels.ReadableByteChannel;
+
+import static java.io.File.createTempFile;
+import static java.nio.channels.Channels.newChannel;
+
+/**
+ * Developer API for now, intentionally remove public visibility
+ */
+class PytorchModelWrapper {
+  static JTensor[] modelForwardNative(
+          long nativeRef, boolean isTraining, float[][] storage, int[] offset, int[][] shape) {
+    return (JTensor[]) PytorchModel.modelForwardNative(nativeRef, isTraining,
+      storage, offset, shape);
+  }
+
+  static JTensor[] modelBackwardNative(
+          long nativeRef, float[][] storage, int[] offset, int[][] shape) {
+    return (JTensor[]) PytorchModel.modelBackwardNative(nativeRef, storage, offset, shape);
+  }
+
+  static JTensor lossForwardNative(
+          long nativeRef, float[][] input_storage, int[] input_offset, int[][] input_shape,
+          float[][] label_storage, int[] label_offset, int[][] label_shape) {
+    return (JTensor) PytorchModel.lossForwardNative(nativeRef, input_storage, input_offset,
+     input_shape, label_storage, label_offset, label_shape);
+  }
+
+  static JTensor[] lossBackwardNative(long nativeRef) {
+    return (JTensor[]) PytorchModel.lossBackwardNative(nativeRef);
+  }
+
+}