[jboss-user] [JBoss Microcontainer Development] New message: "Re: Pluggable dependency resolver"

[Thomas Diesler]

User development,

A new message was posted in the thread "Pluggable dependency resolver":

http://community.jboss.org/message/521271#521271

Author  : Thomas Diesler
Profile : http://community.jboss.org/people/thomas.diesler@jboss.com

Message:
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Am I right to understand that
 
* Each deployment bundle mapps to a ControllerContext. 

* Each ControllerContext may have >0 dependencies. 

* You call ResolverMatcher for each installed bundle 

* You get multiple sets potential matches
 
How do you consolidate the sets of potential matches such that you end up with a consisten solution?
 
A1 can get wired to B1 and X1
B1 can get wired to X1 or X2
 
only when B1 gets wired to X1 can A1 get wired at all
 
Conceptually the MC resolver should support the semantics of
 
http://www.osgi.org/javadoc/r4v42/org/osgi/service/packageadmin/PackageAdmin.html#resolveBundles(org.osgi.framework.Bundle[])
 
also, there needs to be a notion of 'refresh', which may drop existing wirings and establish new ones to potentially updated bundles
 
http://www.osgi.org/javadoc/r4v42/org/osgi/service/packageadmin/PackageAdmin.html#refreshPackages(org.osgi.framework.Bundle[])
 
There is also a requirement to do a 'try run' of bundle resolution. This would allow to answer a question like: If I install these bundles will I end up with a consistent result where everything gets resolved? To answer this question the running system must not be affected - remember, you cannot "unresolve" a bundle.
 
In real life, you would give a provisioning system a small set of top level bundles and a pointer to a repository. The provisioning system needs to figure out if and how the complete set of transitive dependencies can be sattisfied before it modifies the running system in any way.

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