Hi Hidemote, Graeme, please excuse my ignorance - as said before, I am Java agnostic, and my question might be off target... Hidemote mentioned the use of the factory pattern at GGF already, and other people I know which do Java issued similar statements. How does that actually compare to other languages? E.g. in C/C++, you can usually link your code against a specific _API_ in a shared library - as long as a library implements the same API, there is no need to recompile (just exchange library). Also, in C/C++ it is possible to implement an API with plugins: so you create a thin API layer, which forwards to dunamically loaded plugins, which can then provide different implementations of the API calls. The latter way is what we actually do in our C++ implementation (plugins are called adaptors though). The difference I see is actually that in both cases, the fact that the API is implemented by different vendors is completely hidden on API level, w/o the need for any additional patterns like factories. So, is there a difference between these approaches? And if not: what is the advantage of the factory approach? Thanks, Andre. Quoting [Hidemoto Nakada] (May 17 2006):
All,
I have a question on the Java Binding. Does the current Java binding include explicit factory notion?
Factory mechanism is important to - reuse a source code with several implementation of the API without modification of the code. - leverage several implementation simultaneously from one client code.
One good example of factory design can be found in the Dom parser definition; org.w3c.dom.DomImplementation. When you create a Dom document
- get a DomImplementation from org.w3c.dom.bootstrap.DomImplementationRegistory - then create a Document object using DomImplementation.
This mechanism might be too complicated for SAGA, but I think some flavor of this is required.
-hidemoto
-- "So much time, so little to do..." -- Garfield