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https://issues.apache.org/jira/browse/FELIX-2899?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13016413#comment-13016413
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Simon Chemouil commented on FELIX-2899:
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Hi, commenting because I had a similar idea some time ago, and reached the same
conclusion as Peter that identifying strongly connected components in the
static dependency graph of Java classes (and packages) is the best bet. And
there's already an optimal algorithm for that ;-). Refinements &
parametrization should come later (e.g: should the tool be allowed to move
classes to another package, should interfaces be extracted for API needs,
should factories be created and exposed as a DS component, etc).
Anyway, after thinking about this for some time, I came to the conclusion that
doing an "out of the box" solution is a lot of work, and probably make a very
intense GSoC :-).
If there was such a tool, it would definitely be an enabler for OSGi and allow
many projects (including many open source Java projects) to become more modular
at a much lower cost. I hope the GSoC team will accept it.
When they do, good luck with the coding :-).
> [GSoc 2011]Bndtools based OSGi bundles maker project
> ----------------------------------------------------
>
> Key: FELIX-2899
> URL: https://issues.apache.org/jira/browse/FELIX-2899
> Project: Felix
> Issue Type: Task
> Environment: Eclipse platform, this project add a new tool for Felix
> users to improve OSGi bundles development process in Eclipse environment
> Reporter: Tiger Gui
> Assignee: Peter Kriens
> Labels: gsoc, gsoc2011, mentor, mentoring
> Original Estimate: 1680h
> Remaining Estimate: 1680h
>
> OSGi(Open Service Gateway Initiative) is a worldwide consortium of technology
> innovators that advances a proven and
> mature process to create open specifications that enable the modular assembly
> of software built with Java technology.
> It is becoming more and more popular in Java Desktop or Web application
> developmenent especially when we are working on
> some huge project, as it is growing more and more complex, OSGi can help
> us.Developing with OSGi technology means
> developing bundles: the OSGi components. Bundles are modules.
> OSGi is a good thing, but coin has two sides. Usually the development process
> with OSGi will be more troublesome. Suppose
> that we are in this scenario. We use a interface Greeting to say hello to our
> customers , but we should say different words to different kind of customers
> , so we have two implemention class for Greeting interface, we
> name them BasicGreeting and GreatGreeting.
> If we develop this application in a traditional OSGi way, we should create at
> lease 3 projects (or bundles) in our IDE (Eclipse for example).
> one service define bundle, two service supply bundles, it's a long list in
> our workspace.Isn't it troublesome? If we just
> write these codes in a Jave project and some tool can help us to split this
> project in OSGi way and export 3 jar files, isn't it cool?
> So i want to build OSGi split tool for Java project, it can also be used to
> split and refactor our exist huge project in OSGi way. This
> is very important. In some huge application, how to manage components in a
> convinent way is an art, so far, OSGi is the best solution
> that we can find. But the refactor and split for exist huge project is
> complex and painful. This tool will help us to do this job.
> We want to build a bnd(tools) based OSGi bunlles maker project, it will help
> us analyse java application and split the whole project into several OSGi
> bundles.
> Suppose that we write code in good style, define service in interface,
> implement the service by the implemention class of the interface
> and put similar service in a package. This tool can analyse source code,
> supply vari-size grained split and refactor suggestions, show
> the analyse result in a GUI view and we can change split solution manually,
> then it will split the project into several projects.
> Function lists:
> 1. configuration
> Define default split/refactor solution for this tool. For example,assign
> default interface split particle or package split partical. Or may be
> we can just split the project by function module define, similar with
> M(Module)-V(View)-C(control) develop pattern. Or in some other ways.
> 2. analyse module
> It can analyse project source code, make clear of class dependency
> relationship and give us a graphical view analyse result, this is default
> split solution, and we can change it as we like.
> The trick is to find strongly coupled packages. These are packages that are
> in a cycle. A -> B -> C -> A. Normally I find that these packages should be
> in the same bundle. In bnd (the current next branch) I already can calculate
> those strongly connected packages. In general, I find that many, especially
> larger, bundles consist of a number of subsystems.
> These subsystems have dependencies on each other, however, by definition
> there is no cycle between these subsystem dependencies (otherwise they would
> be strongly connected and be part of the same subsystem).
> There should be the following types of subsystems:
> API - Self contained, no internal dependencies. All exported/imported. Very
> few dependencies. The OSGi specification packages are prime examples. Having
> imports in these packages is always suspect. In my experience, API must be
> maintained independently but carried in the bundle that implements the API.
> Library - Exported code == implementation. Few imports, everything is
> exported and in general packages are not substitutable.
> Implementation - Private code. No exports, many imports, If it provides an
> API it should carry the API packages.
> Bridge - Connects an external subsystem to an internal subsystem. Imports
> impl. code, no exports. This case is special because they tend to drag in a
> lot dependencies that are only required when the dependency is already there.
> For example, a subsystem can provide packages that make it useful in Spring.
> I.e. it does not require Spring but when other people use spring the package
> can be used in that connected world. Another example is bnd. It is an ant
> task but it should only require ant when it runs inside ant.
> 3. split and export module
> We can select split the project into serveral small project or just export
> the project as OSGi bundles way, this step rely on pre-step analyse
> and saved split/refactor solution.
> We have finished demo for this project, you can check it on line here [1].
> [1] http://code.google.com/p/osgimaker/wiki/Quick_Start
> Additional information:
> My name is Tiger Gui, come from Beijing, China. I have been working with OSGi
> for 3 years, familiar with OSGi Felix framework and Eclipse Equinox
> framework. Once we helped one customer of our professor to split a very big
> complex project into OSGi bundles, it cost us much time, several months to
> finish this job. So, i started to think about creating a smart tool which can
> help us to do some boring job. Of course, it request high-level of Artificial
> Intelligence to do this project well, but we can do it step by step, during
> this summer, i would like to finish an available OSGi bundle maker tool which
> has special level of intelligence to analyse our project and split.
> I have finish much research job and ordered Felix developer mail list and
> Equinox developer mail list, discuss this topic in mail list with open source
> guys. Especially my mentor Peter Kriens, he gave me many good advises and
> work with me together toward to a successful project, so i have confidence
> to achieve the goal this summer. If you guys have any other advises for this
> project, please let me know, My email account and GTalk account are both
> [email protected]. Thank you.
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