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From Jin Mingjian <jin....@gmail.com>
Subject Re: The OSGi-Harmony Runtime
Date Sun, 16 Aug 2009 11:07:59 GMT
galaxy, still good work:) I am not the man to evaluate your work:)

your work = mini Harmony jre + Felix?

such as one question:
how your runtime works? Does it support mixed jar usage?(seem your "For B"?
A bundle jar can be seen as a bundle or a pure application jar depended on
the context. there are some interesting things happened here)




2009/8/16 galaxy <tian.galaxy@gmail.com>

> I'm sorry but I think you should have missed some thing in the review .the
> OSGi framework I use is Felix, and all the security and dynamic comes from
> it and built in with it,
> if you want to find the osgi-ed security and dynamic
> does this answer your question ?
>
> 2009/8/16 Jin Mingjian <jin.phd@gmail.com>
>
> > interesting. I'd like to mainly examine the dynamic and security of
> > your OSGi-Harmony runtime when the codes is ready.
> >
> > 2009/8/16 Xiao-Feng Li <xiaofeng.li@gmail.com>
> >
> > > Good work! How much is the size of the minimum OSGi-ed JRE?
> > >
> > > Thanks,
> > > xiaofeng
> > >
> > > On Sun, Aug 16, 2009 at 3:22 PM, galaxy<tian.galaxy@gmail.com> wrote:
> > > > Hi  all
> > > >    Now the code for OSGi-ed Runtime of Harmony is almost complete ,
> I'd
> > > > like to give a review of
> > > > the work so far.The code and usage will be uploaded together soon
> > > >
> > > > Introduction To OSGi-ed JRE
> > > >
> > > >
> > > >
> > > > 1 : The main purpose
> > > >
> > > > OSGi has become one of the best ways to govern the jar files in a
> > number
> > > of
> > > > applications Such as the power it exhibits in eclipse .And as we all
> > know
> > > > ,the Harmony runtime is a modularized one and each module , with its
> > > > manifest file , is just like one bundle in the OSGi framework .So we
> > are
> > > > think of governing the modules in Harmony runtime in a OSGi-ed way.
> > > >
> > > >
> > > >
> > > > 2 : Ways to meet the main purpose
> > > >
> > > >       Naturally, there are two ways to meet this purpose:
> > > >
> > > > A  Implementing the OSGi framework in VM in C/C++ to govern all the
> > java
> > > > modules
> > > >
> > > > B  Using one of the OSGi-ed framework implemented in java to
> > implemented
> > > a
> > > > half OSGi-ed JRE.
> > > >
> > > >       Finally I picked the plan B with the well known OSGi framework
> > > :Felix
> > > > .And the reasons are as follows
> > > >
> > > > First : Implementing a OSGi-ed framework from scratch in c/c++ in the
> > vm
> > > is
> > > > difficult and time-consuming .
> > > >
> > > > Second : Plan A suffers from the facts that implementations differs
> > huge
> > > > from VM to VM .Plan B won’t have this kind of problem as long as the
> > > modules
> > > > comply with the OSGi specifications and we have a adapted java.exe ,
> > the
> > > > rest is nearly the same.
> > > >
> > > > Third : Beside the framework ,each OSGi implementation has a lot of
> > > add-ons
> > > > .This will facilitate future development of new features and
> utilities
> > > .For
> > > > example : the could use the bundle fileinstall to install all the jar
> > > files
> > > > lies in a folder ,very helpful in certain circumstances.This could be
> > > done
> > > > rapidly if we choose plan B .
> > > >
> > > >
> > > >
> > > > 3 : Problems and fixes
> > > >
> > > > The difficulties ,or the main tasks ,of this project are as follows
> > > >
> > > > A     Find the minimum working environment of OSGi-framework and
> modify
> > > the
> > > > rest modules in Harmony ,mainly the manifest file ,to resolve the
> > > coupling
> > > >
> > > > B     Modify the classloading mechanism and booting of the jre to be
> > able
> > > > run normal java applications
> > > >
> > > > And the fixes are
> > > >
> > > > For A:
> > > >
> > > > Harmony is a modularized runtime .So determine the minimum working
> > > > environment is no more than choose the right module to stay with the
> VM
> > > > .However ,although the coupling is little , it does exist . So a
> > > > modification of the module is necessary ,mainly the manifest file
> .And
> > as
> > > I
> > > > want  to remain the original structure of Harmony as largely as
> > possible
> > > > ,more contents (classes ) will be included in the minimum environment
> > > other
> > > > than splitting the modules apart .The final jre include the following
> > > > component :
> > > >
> > > >
> > > >
> > > > luni.jar
> > > >
> > > > annotation.jar
> > > >
> > > > security.jar
> > > >
> > > > math.jar
> > > >
> > > > text.jar
> > > >
> > > > regex.jar
> > > >
> > > > noi_char.jar
> > > >
> > > > nio.jar
> > > >
> > > > logging.jar
> > > >
> > > > concurrent.jar
> > > >
> > > > archive.jar
> > > >
> > > > the ICU4J folder.
> > > >
> > > >
> > > >
> > > > The remaining jars are governed by the OSGi framework to handle. One
> > more
> > > > thing to mention is the two classes
> > > >
> ,”java.beans.PropertyChangelinstener”,”java.beans.PropertyChangeEvent”
> > > has
> > > > to be moved out of beans.jar .This is because of the coupling of
> > > beans.jar
> > > > with other modules in the minimum runtime .Well the good thing is
> these
> > > two
> > > > classes havn’t imports any other classes in the modules governed by
> the
> > > OSGi
> > > > framework .I think we could include them in any modules lie in the
> > > minimum
> > > > runtime as long as the VM could find them .
> > > >
> > > >
> > > >
> > > > For B:
> > > >
> > > > I added one extra sphere between the VM and the main class to run
> > > > .org.apache.osgi.FelixStarter. , the following is done in this class
> > > >
> > > > First: Loading the configurations and Start Felix ,the OSGi framework
> > we
> > > use
> > > >
> > > > Second: Initializing the class org.apache.osgi.OsgiClassLoader ,this
> > > class
> > > > will load the main class and subsequently all the classes used in the
> > > main
> > > > class
> > > >
> > > > Third: Transfer the arguments to the “real “ main class ,invoke the
> > main
> > > > method .
> > > >
> > > >
> > > >
> > > > The sequence of class loading is as follows :
> > > >
> > > >
> > > >
> > > > First : Check the class name to determine whether it should be loaded
> > by
> > > the
> > > > parent class loader .This work is done by specifying the
> > > > “org.osgi.framework.bootdelegation” property to include all the
> package
> > > > names in the modules stays in the VM .
> > > >
> > > > Second : load the classes in the bundle governed by the framework .I
> > will
> > > > examine each bundle's export and import property to search for the
> > class
> > > > name ;
> > > >
> > > > Third : the classes in the application’s class path .
> > > >
> > > > Finally : we could not find the class and a ClassNotFoundException
> will
> > > be
> > > > thrown .
> > > >
> > > >
> > > >
> > > > Both the OSGi framework and the Harmony do not allow the define ,
> > imports
> > > or
> > > > exports of java.* classes and packages ,so a lot of examines has been
> > > > removed to facilitate our purpose .
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > --
> > > > regards
> > > > Tian
> > > >
> > >
> > >
> > >
> > > --
> > > http://people.apache.org/~xli
> > >
> >
>
>
>
> --
> regards
> Tian
>

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