[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [List Home]
[equinox-dev] support for component API refactoring


To date we have operated under a 100% binary compatibility rule with an underlying assumption that the original code itself could not be modified.  Over time our API has become ladden with old methods, old package and class names, old extension points, ...  The challenge is keeping the API fresh, clean and clear while not breaking existing code which, according to the assumption, cannot be changed.

The importance of API maintenance should not be underestimated.  It is vital both for the smooth consumption of components as they evolve but for its effect on producer/consumer trust.

With that in mind, it may be interesting to challenge the assumption the consumer's code cannot change and instead assume that the consumer does not change the code -- allow the producer change it for them.  This direction was discussed amongst a number of us at the OSGi World Congress a few weeks ago.  There are several flavours but here is the basic idea.

- The producer of an API, for example, changes the name of a package/class/method from A to B
- the producer also creates an aspect definition that "co-opts" all consumers and modifies references to the old package/class/method to reference the new package/class/method.
- this can capture package, class and mehod changes
- there are corner cases involving reflection and OSGi service lookup etc that may be more challenging

Similarly, a registry munging mechanism would be required to update extension/extension point usage in the face of renamed or refactored plugins.

Is there any interest in looking at this problem (I'm thinking specifically from the aspect folks).  Thisis a pretty mundane use of aspects but it would be hugely useful.

Jeff