Observer defines a one-to-many dependency between a Subject and its subscribers. The Subject keeps registered observers, and notify() calls each observer’s update() method when new content arrives. section 12.1.3
A typical implementation provides:
- Independent subscribers such as LogReport, GraphReport, TableReport, and FanClubReport, each processing updates differently. section 12.1.3
Baseball reports
BaseballReporter publishes events. Each report registers with attach(), receives update(), and can retrieve the current Event. FanClubReport filters for George, produces a bulletin, then detaches itself.
