Functional IoC example

Contrast the text-based Bash script example to a web application where the user is in control:

In a GUI application, control is inverted. Instead of the program forcing the next user interaction, the user is mostly in control of what happens next. The IoC container is a web application framework that runs an event loop and handles the callback when the user clicks on controls, such as an item in the drop-down list or a submit button.

For some J2EE applications, IoC can also come in the form of XML configuration files that are injected into a Spring framework.

In a product shopping example, dependencies would be things such as Select Product or Enter Shipping Address. In our decorator implementation, dependencies include Authorization, LoadBalancing, etc., each of which decorate the request.  Our IoC container is the decorator framework where functions like Authorization and LoadBalancing implement the Client interface.