Bug 347028

Description Thomas Watson 2011-05-24 13:58:15 EDT

I will admit up front that this idea is not completely thought out, but I wanted to record an enhancement bug so I would not loose the work I have done so far on this.

Right now the RegionDigraph has a concept of a RegionDigraphVisitor which is great and allows for one to traverse the graph along the connection edges.  But in order to traverse the edges properly the visitor must have access to real objects that can be shared across the connection (i.e. Bundle, BundleCapability, BundleRevision, ServiceReference).  This is required because the RegionFilter method only has isAllowed methods that take these types and to follow a connection correctly you need to make sure the RegionFilter allows the thing you are trying to share.

But some scenarios exist where you want to traverse the graph but you don't have access to the real objects.  My idea is to add the following method to RegionFilter:

/**
 * Determines whether this filter allows the given name space with the given
 * attributes.
 * @param namespace the name space
 * @param attributes the attributes to check if they are allowed
 * @return <code>true</code> if the name space and attributes are allowed and 
 * <code>false</code> otherwise
 */
public boolean isAllowed(String namespace, Map<String, ?> attributes);

This would allow a visitor to traverse the graph for a specific name space and a map of attributes to match again.  This may be useful for things like subsystems where you want to determine if there are connections that allow visibility to specific things.  For example, does a Region have connections to other regions that would allow a specific bundle-symbolic-name and version threw?