On 09/04/2013 05:27 PM, mark.reinh...@oracle.com wrote:
2013/8/30 5:20 -0700, david.ll...@redhat.com:
... In addition, many best practices have emerged
that (partially or wholly) contradict the original design intent of
these systems (OSGi also falls into this category).
Do you have links to any good descriptions of these best practices?
That'd be helpful.
Not a lot as links, as mostly they are "community knowledge" among our
various teams, but here's a couple for each that I can find relatively
quickly:
For Maven:
* Version ranges considered harmful [1] [2] [3] [4] (and probably more);
we disallow them within our own products for stability reasons
* Transitive-by-default causes problems in mid to large projects due to
extensive conflicts [can't find the discussion...]; fix is to use and
verify exclusions, specify "provided" scope, and use
maven-enforcer-plugin [5] to ban transitive dependencies
For OSGi:
* Using the full capabilities of range dependencies can cause resolution
to be NP-complete; best practice is to use ranges in a more restricted
manner [6]
* Require-Bundle not recommended due to lack of hiding non-public
packages among other things [no link] (however, to be fair this is only
due to the way Require-Bundle was designed; it's not an inherent flaw,
but it is a best practice not to use it, hence it fits the criteria)
As with many so-called "best practices" there are those who disagree
with some or all of them; I'm not going to argue the finer points of
each one. I'm just pointing out that just copying a given mechanism and
adapting it straight to a somewhat similar but also somewhat different
use case is doubly dangerous - on one hand, it is hard to know what went
into the design of these mechanisms; and on the other hand, there is a
considerable base of knowledge that comes from third parties (or just
the general public) that sheds additional light on the pros and cons of
these mechanisms as well.
[1]
http://maven.40175.n5.nabble.com/Version-ranges-not-working-td5723909i40.html
[2] http://stackoverflow.com/a/7169847/2033093
[3] http://stackoverflow.com/a/3882490/2033093
[4] http://grokbase.com/p/maven/users/129vwgkd1c/version-ranges-not-working
[5]
http://maven.apache.org/enforcer/enforcer-rules/banTransitiveDependencies.html
[6] http://wiki.apidesign.org/wiki/RangeDependenciesAnalysed
--
- DML
