What approach should an architect recommend for retrieving opportunity details and updating them in real-time as an atomic operation?

The recommendation to use a custom Apex class with a webservice method that performs both retrieving and updating opportunity details as an atomic operation is an effective approach for several reasons.

This method allows for the encapsulation of both the data retrieval and the update logic within a single transaction. By defining a webservice method, the architect can ensure that the operations are executed in a controlled environment where error handling can be managed effectively. If either the retrieval or the update fails, the entire operation can be rolled back, which is vital for maintaining data consistency.

Additionally, this approach provides the architect the flexibility to implement complex business logic as needed during the update and retrieval processes. For instance, validation rules or triggers can easily be incorporated into the Apex class, ensuring that business rules are enforced before any changes are committed.

Custom Apex classes also allow for synchronous processing, which ensures that the user receives immediate feedback upon completion of the operation. This is especially beneficial for real-time updates, making the solution responsive to the user's needs.

Other options, while they may be functional for their intended purposes, do not align as well with the requirement for an atomic operation where the updates and retrieval are tightly coupled. For instance, publisher actions or streaming APIs are more suited for loosely coupled integrations that focus