OrderSourceProvider constructor

const OrderSourceProvider()

A strategy interface for providing an alternative source of order metadata for a given object.

This is useful when sorting or prioritizing objects based on external metadata rather than relying solely on their own Ordered or PriorityOrdered interface.

For example, an object may not directly implement Ordered, but its order may be derived from another associated object (its “order source”).

⚙️ How It Works:

  • The provided getOrderSource method may return:
    • A single object that implements Ordered
    • An Iterable of multiple such objects
    • null if no order source is available

📌 Example

class PodOrderSourceProvider extends OrderSourceProvider {
  final Map<Object, Object> _orderSources;

  PodOrderSourceProvider(this._orderSources);

  @override
  Object? getOrderSource(Object obj) => _orderSources[obj];
}

This allows indirect ordering via metadata while keeping the target class clean.

Implementation

const OrderSourceProvider();