MultiExecutionListener

Aggregates several OrderExecutionListener instances and forwards every order-lifecycle callback to them.

class MultiExecutionListener {
public:
  explicit MultiExecutionListener(SubscriberId id);

  void start();
  void stop();

  SubscriberId  id()   const;
  SubscriberMode mode() const;          // always PUSH

  void addListener(OrderExecutionListenerRef l);

  // Order-lifecycle fan-out
  void onOrderSubmitted     (const Order&);
  void onOrderAccepted      (const Order&);
  void onOrderPartiallyFilled(const Order&, Quantity);
  void onOrderFilled        (const Order&);
  void onOrderCanceled      (const Order&);
  void onOrderExpired       (const Order&);
  void onOrderRejected      (const Order&, const std::string& reason);
  void onOrderReplaced      (const Order& oldOrd, const Order& newOrd);
};

Purpose

• Act as a broadcast hub so multiple components (PNL tracker, logger, GUI) can receive execution events without each being subscribed separately.

Behaviour

Action	Detail
addListener()	Stores unique listeners; duplicates (by id()) are ignored.
Callbacks	Loops through _listeners and forwards the event.
Threading	Declares SubscriberMode::PUSH; intended for EventBus push threads.

Notes

• No dynamic removal; recreate the object if listener set changes.
• static_assert ensures the class itself satisfies OrderExecutionListener concept.