code: synchronized PaymentChannelServer setConnectedHandler(PaymentChannelServer connectedHandler, boolean override) {
          if (this.connectedHandler != null && !override)
              return this.connectedHandler;
          this.connectedHandler = connectedHandler;
          return connectedHandler;
      }
docs: Attempts to connect the given handler to this, returning true if it is the new handler, false if there was
  already one attached.