Timothy Wall wrote:

The gstreamer-java code is at http://code.google.com/p/gstreamer-java/

Basically what I do is treat the treat the raw gstreamer pointers as an opaque handle (since they really are), and use proxies to access them.

e.g. in your case:

class MediaObject { Pointer handle; public MediaObject() { PointerByReference phi = new PointerByReference(); media.createHandle(phi); handle = phi.getValue(); } public void readImage() { Media.INSTANCE.readImage(handle); } protected void finalize() { Media.INSTANCE.destroyHandle(handle); } }

I did this mainly because I wanted to put a more java-ish API over the raw gst_object_fiddle_with_bar() type API.

You can use the new TypeMapper API in JNA 2.4 to implement auto-conversion to/from proxy objects. So if you don't want to write wrapper functions for each method, like above, you can use an ArgumentConverter to automagically pass MediaObject.handle to the underlying API.

e.g.

interface Media { static final TypeMapper TYPE_MAPPER = new DefaultTypeMapper() {{ addArgumentConverter(MediaObject.class,new ArgumentConverter() { public Object toNative(Object obj) { return ((MediaObject)obj).handle; } }); }}; public static final Media INSTANCE = Native.loadLibrary("media", Media.class, new HashMap() {{ put(Library.OPTION_TYPE_MAPPER, TYPE_MAPPER); }}); public void readImage(MediaObject obj); public void frobImage(MediaObject obj); }

You should then be able to do MediaObject obj = new MediaObject(); Media.INSTANCE.readImage(obj); Media.INSTANCE.frobImage(obj);

I think a copy constructor is definitely needed. Also a way to get the raw pointer value as a long could be useful in some cases.

I'm not sure having non-public ctor/getters on Pointer really buys that much safety - after all, JNA already lets people do pretty dangerous things, and you can bypass it using malloc. e.g. Pointer p = libc.malloc(4); p.setInt(0, 0xdeadbeef); p = p.getPointer(0); // p now points to 0xdeadbeef