RangeDependencies

From APIDesign

Dependencies are important part of every Module system. Dependencies are here to abstract the complex relationship between a module and environment it needs for its own execution, compilation, linkage, etc. Dependencies are always a simplification of the real requirements, but that does not stop people from inventing new and new ways how to specify them more precisely.

It has already been discussed that dependency needs some lower bound (the moment when the needed API is first introduced) and also some higher bound (as incompatible changes are so often). How do we formalize it? Well, let's use some mathematics and describe dependencies as interval! As a result a dependency on any compatible version 1.4.3 and later, would be written as .

This looks like a very good solution. It is also very rationalistic. It is reusing knowledge gained by mathematics in past and thus it cannot be wrong! Moreover it is general enough - one can use the same notation to express equality dependency by writing . And also it is flexible as one can also depend on a smaller range of versions . Last, but not least this solution also supports some level of cluelessness as it builds on something every programmer must have heard of at own school days.

No wonder that everyone one who wants to be seen as providing well designed, deeply thought out, powerful and theoretically backed solution will choose intervals. This is probably the reason why OSGi decided to use this kind of dependencies.

Too Much is Overkill!

Well, it seems that OSGi comrades made a mistake by choosing RangeDependencies. They created something that is flexible, as flexible that it is no longer manageable.