Expert Python Programming - Third Edition

Observer

The observer pattern is used to notify a list of objects about a state change of the observed component. We have already discussed this pattern briefly in the previous chapter, but here we will discuss some practical examples of a situation where this pattern could be applied.

For instance, let's imagine we have an application that stores marketing materials (briefs, presentations, videos, and flyers) and legal documents in digital form for the sales department of a large company. The company is large, with many sales representatives, and has multiple documents to maintain. A system performs multiple tasks to process these digital documents and make sure that sales representatives are always aware which materials have been updated ...