Connie's Convenience Store - About Peter Coad

30 Connie’s Convenience Store Establishing Responsibilities for Problem-Domain Objects
Establish responsibilities: “who I know.”
Who does a person object know?
#72. “Establish Objects I Know” Strategy establishing responsibilities /
who I know (fundamentals)
• This is an aspect of a software object coming to life: “I know other objects, ones that are
related to the actual object that I’m an abstraction of.”
• Select connecting objects to satisfy these two purposes:
To directly know “to whom to send a message” (within one or more scenarios).
To answer a query about objects that are directly related to it.
Here’s some specific help.
#74. “Establish Actor and Participant establishing responsibilities /
Object Connections” Strategy who I know (pattern players)
• For an actor, include an object connection to: its participants.
• For a participant, include an object connection to: its actor, its transactions.
A person object knows its participant objects. And each participant object knows its
corresponding person object (Figure 1–20):
name
address
phone
Establish responsibilities: “what I do.”
Person Cashier
1 1
Figure 1–20: Person: “who I know.”
#89. “Basic Services” Strategy establishing responsibilities /
what I do (fundamentals)
• The basic service, done by all, are not shown in an object model, except within specific
scenario views that might use them.
• The basics: get, set; add (a connecting object), remove (a connecting object); create
(something a class does) and initialize, delete.
• Note: attributes are private, by convention. In scenarios, use “get ” and
“set ” services to access attribute values.
• The basic DM services—for data management objects—are: search, load, and save.