To build on the work that was done for SWITCHYARD-1268 :

1) The PropertyResolver interface's resolveProperty(String) method should return an Object, not a String.

2) Values inside dollar-curlies should be able to specify a default. This way, properties can be overridden for tests, but have sensible values otherwise. For example: <http port="$

"/> would resolve to 8080, unless a -DhttpPort=9090 is specified to override it, in which case it would resolve to 9090. This is modeled after JBoss AS.