Hi,
On 26.05.2009, at 19:01, Vrignaud Etienne wrote:
Hi,
Here is the issue:
When you/iPOJO call getServiceReferences the framework should returns
only "accessible" services. "Accessible" means that you (the bundle)
can access to the service object in term of class loading. So, it
generally means : must use the same service interface class as the
provider (that's why providers and consumers should import the same
package).
So, let's back to getServiceReferences. iPOJO as all the other OSGi
bundle, relies on it and make the assumption that resulting service
objects can be used by the bundle.
However, in your case, it's a little more tricky.
You have two "class" spaces:
- the space V1 containing the api v1 classes
- the space V2 containing the api v2 classes
Your manifest are correct and set correctly the import package range:
so V1 bundles import/ export api [1.0.0,1.0.0] and V2 bundles import/
export api [2.0.0,2.0.0].
So, if we follow the "Accessible" rules, V2 bundles cannot get
services exported by V1 bundles (and V1 bundles cannot access to
services exported by V2 bundles).
but (there is always a but), when a V2 bundles ask for service it
receives services from V2 bundles, and from V1 bundles... Why? just
because it sounds tricky to detect accessible services when using
OSGi
Service Factories (used by iPOJO to achieve the laziness) .
So, I don't have any good solution to turn around this issue. In
fact,
I don't know if there is one (if somebody has one, feel free to
mention it ;-))
I am sorry but I don't understand where is really the issue.
As you said in you message, V2 bundles cannot get services exported
by v1
bundles.
So for me that's enough. Why do we need to add some filtering
informations.
Because it should work but don't with ServiceFactory :-(
ServiceFactories are there to support laziness and custom service
object creation. So, the framework can't really check if the service
is accessible, because it requires an object not yet created...
I have made some tries with OSGi bundles regarding that point. Without
factories, I agree.
What I have noticed is that the PackageAdmin OSGi service provide many
informations that are helpful.
I tried the usage of those two methods:
- ExportedPackage getExportedPackage(Bundle bundle);
- RequiredBundle[] getRequiredBundles(String symbolicName);
Don't you think that you can use that kind of verification to avoid
the
issue.
Because as you agreed OSGi knows the "links".
------------------------------------------------------------------------------------------
Here are some sample codes that check the "OSGi links" (Ugly
implementations
with many if, for, if, for, if. But it does the job.)
Case 1: Import-Package usage as bnd does.
-------
/**
* Return true if the specified 'bundle' imports some packages of
the
'importedBundle'
*/
private boolean isImportedBy(Bundle importedBundle, Bundle bundle)
{
ExportedPackage[] exportedPackages =
getPackageAdmin().getExportedPackages(importedBundle);
if (exportedPackages != null)
{
for (ExportedPackage exportedPackage : exportedPackages)
{
Bundle[] importingBundles =
exportedPackage.getImportingBundles();
if (importingBundles != null)
{
for (Bundle importingBundle : importingBundles)
{
if (importingBundle == bundle)
{
return true;
}
}
}
}
}
return false;
}
Case 2: Require-Bundle usage as done by all the Equinox bundles
-------
/**
* Return true is the specified 'bundle' requires the
'requiredBundle'.
*/
private boolean isRequiredBy(Bundle requiredBundle, Bundle bundle)
{
RequiredBundle[] requiredBundles =
getPackageAdmin
().getRequiredBundles(requiredBundle.getSymbolicName());
for (RequiredBundle required : requiredBundles)
{
if (required.getBundle() == requiredBundle)
{
Bundle[] requiringBundles =
required.getRequiringBundles();
for (Bundle requiringBundle : requiringBundles)
{
if (requiringBundle == bundle)
{
return true;
}
}
}
}
return false;
}
private PackageAdmin getPackageAdmin()
{
return (PackageAdmin)
bundleContext.getService(packageAdminRef);
}
Right, I will see if I can try to check accessibility myself (i.e. in
iPOJO) thanks to the package admin. I keep you posted
Regards,
Clement
Best,
/Etienne
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