158 .225 Study Guide - Final Guide: Loose Coupling, Object Model, State Pattern
Document Summary
We want to be able to reuse as many things as possible. Heuristic allowing a person to discover or learn something for themselves. Responsibility for persistence is a large-grained responsibility eg. user. Patterns provide a vocabulary of design such as: state, straegy, fa ade. Something that knows a lot about certain things. Assign a responsibility to the object that has the information necessary. A god object lacks cohesion and has too many responsibilities. What object in the domain receives requests for work from the ui layer. Choose a class whose name suggests the overall system , or represents the use case scenario. Coupling describes the degree of togetherness, and is reflected by the number of links. To create reusable components that are resilient to change. A measure of how strongly related and focused the responsibilities of a class are. Low cohesion do too many unrelated things (undesirable).
