code: public static void preRegister(Context context) {
          context.put(FSInfo.class, new Context.Factory<FSInfo>() {
              public FSInfo make(Context c) {
                  FSInfo instance = new CacheFSInfo();
                  c.put(FSInfo.class, instance);
                  return instance;
              }
          });
      }
docs: Register a Context.Factory to create a CacheFSInfo.