Hands-On Design Patterns and Best Practices with Julia

Applying the delegation pattern to a banking use case

The delegation pattern is the idea of creating a new object by wrapping an existing one called the parent object. In order to reuse the object's features, the functions that have been defined for the new object can be delegated (also known as forwarded) to the parent.

Suppose that we have access to a banking library that provides some basic account management functionality. To understand how it works, let's take a look at the source code. 

A bank account has been designed with the following mutable data structure:

mutable struct Account    account_number::String    balance::Float64    date_opened::Dateend

As part of the programming interface, the library also provides the field accessors (see ...