A more concrete example would be if you want to store a JMS message. JMS
provides an interface for Message and another interface Session in order
to create it.
I guess the Message interface is always something to be exported whereas
the real message type e.g. MantaMqMessage which implements this
interface is private property.
So what I have is just a pointer to Message:
Message msg=Session.createMessage(){
return new MantaMqMessage();
}
Serialization is no problem so far because you know the MantaMqMessage
through reflection. But deserialization would have to create a
MantaMqMessage instance but cannot find it since is secretly kept in
some bundle classloader.
Bye,
Andy
Angelo vd Sijpt schrieb:
I'm not quite sure what you're trying to accomplish in that way...
If the references are not necessary when deserializing, make them transient.
If they are necessary, there's something peculiar about your design; is it
really necessary that they are implementations of some interface because
they're used as services, or are they actually just value objects?
Angelo
On Wed, Dec 2, 2009 at 10:49 AM, andrea ziege <[email protected]>wrote:
This is ok I do it the same way:
XStream stream=new XStream();
stream.setClassLoader(Activator.class.getClassLoader());
My problem was that the class I serialize contains references to interfaces
which are visible from my bundle. But the implementation classes are
invisible. This isn't a problem for serialization but for deserialization.
So even DynamicImport doesn't work. So I would need to make the impl
classes
public visible. Which I'm not able in all cases and what is in my opinion a
dirty fix.
Bye,
Andy
2009/12/2 Angelo vd Sijpt <[email protected]>
Maybe I'm going down the wrong path here, but if your bundle B uses
XStream
too, you can make use of that.
XStream will by default use (I believe) the system classloader, and not
the
classloader of bundle B. You can make it use the correct one by passing
your
own classloader:
new XStream(null, new XppDriver(), BundleBClass.class.getClassLoader());
You should make sure BundleBClass is some class that is loaded by the
classloader of bundle B, since that has access to the imported classes
from
bundle A.
Angelo
On Tue, Dec 1, 2009 at 7:44 PM, Ziegenlippe <[email protected]
wrote:
Hello,
I cannot find a satisfying solution to a simple looking problem for
quite
a
while.
The condensation of the problem:
Bundle A
the producer stores objects as xml files (e.g. with XStream)
it exports the /bundle.a/ package which contains the interface /Item/
it
contains a private implementation package /bundle.a.impl/ which
contains
the
item implementation class /ItemImpl/
Bundle B
the consumer needs to load and process /Item/ instances
therefor it imports package /bundle.a/ which contains the /Item/
interface
Problem: loading Item instances in bundle B leads always to
ClassNotFoundExceptions
Even working with the last resort /DynamicImport-Package: * / does not
solve the problem since it imports only exported packages.
From some hints in the internet I got the feeling that this issue is
not
really solved for OSGI. Is there any solution known? How deal others
with
that issue e.g. ActiveMq which claims to be OSGI compliant.
Or am I just on the wrong way?
Thank you in advance,
Andy
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