code: protected Context getContext(ResourceType type) {
      Context c = typeToContext.get(type);
      if (c == null) {
        c = new Context();
        typeToContext.put(type, c);
      }
      return c;
    }
docs: Get the context for a resource type.  Creates the context
  on demand if it doesn't exist.
  
  @param type Type of resource
  @return Appropriate resource context