Case Study [73]

$\bullet$ Goal: Incorporate the Observer, Persistent (Snapshot), Remote Patterns

$\bullet$ Ultimate Object: Many Observers can be notified upon updates, the object lives forever on the disk, and the object can be distributed somewhere else on the network.

$\bullet$ First, consider Observable and Persistent Objects

$\bullet$ Persistence achieved with SQL database or Java's Serializable interface

$\bullet$ Second, consider Persistent and Remote Objects

$\bullet$ Remote Objects achieved with Java's Remote Method Invocation (RMI)