@Override
      public String apply(StackModule input) {
        // TODO Auto-generated method stub
        return new StackId(input.getModuleInfo()).toString();
      }
Encapsulates the work to resolve the latest repo information for a stack.
This class must be used AFTER the stack has created its owned repositories.
ambari-server/src/main/java/org/apache/ambari/server/state/stack/RepoUrlInfoCallable.java