Hook: Define Persistance Streams

Requirement

The in- and output streams for making persistent or restoring the state of the application need to be defined.

Method of Adaptation

Replace Feature

Level of Support

Parameter Pattern

HotSpot

Persistance

Hooks used

Incorporate new Shop

Participants

Shop, NewShop

Changes

1. subclass NewShop of Shop.
2. to define persistance input stream:
1. NewShop.retrievePersistanceInStream overrides Shop.retrievePersistanceInStream .
2. NewShop.retrievePersistanceInStream returns a newly opened stream for reading the application's state.
3. to define persistance output stream:
1. NewShop.retrievePersistanceOutStream overrides Shop.retrievePersistanceOutStream .
2. NewShop.retrievePersistanceOutStream returns a fresh stream for writing the application's state.
4. Incorporate new Shop [NewShop = NewShop].

Comments

• You will usually have to override both methods, as their behavior must be synchronised in some way.