Which statement distinguishes a pattern from a framework?

A pattern is an abstract idea; a framework is actual reusable code

A pattern is large code; a framework is an idea

A framework is smaller than a pattern

Who computes the total of a Sale according to Information Expert?

Sale, because it knows its line items

When should B create instances of A under Creator?

B has the initialising data for A or contains, records or closely uses A

What does Low Coupling advise when choosing between designs?

Choose the one with the fewer dependencies between classes

Choose the one with more classes

2072 Asoj · 8 marks

Pattern vs framework; GRASP patterns

Short answer

A pattern is an abstract solution idea, while a framework is a reusable code skeleton. In GRASP, Information Expert assigns responsibility to the class with the needed data, Creator gives creation to the containing class, and Low Coupling minimizes dependencies to ease change.

How pattern different from framework? Explain information Expert, Creator and Low Coupling design patterns defined by GRASP Design Pattern.

Pattern vs framework

Point	Pattern	Framework
Nature	An idea: description of a problem and its solution	Actual code: reusable classes and libraries
Level	Abstract, design level	Concrete, implementation level
Size	Small, solves one design problem	Large, a whole application skeleton
Use	You implement it yourself in any language	You extend or plug into it
Control	Your code stays in control	The framework calls your code (inversion of control)
Example	Observer, Singleton, Factory	Spring, Struts, Swing

A framework often uses several patterns. Patterns are more general and smaller architectural elements than frameworks.

GRASP patterns

GRASP (General Responsibility Assignment Software Patterns, by Larman) guides the assignment of responsibilities to classes.

1. Information Expert

Problem: what is the basic principle for assigning a responsibility?
Solution: assign it to the class that has the information needed to fulfil it.
Example: who computes the total of a Sale? Sale knows its SalesLineItems, so Sale.getTotal(); each line item knows its quantity and price, so SalesLineItem.getSubtotal().
Benefit: encapsulation, low coupling, high cohesion.

2. Creator

Problem: who should create an instance of class A?
Solution: assign the creation of A to B if B aggregates or contains A, records A, closely uses A, or has the initialising data for A.
Example: Sale contains SalesLineItems, so Sale creates them (Sale.makeLineItem()).

 Sale ---<>--- SalesLineItem
 Sale creates SalesLineItem

3. Low Coupling

Problem: how to reduce the impact of change and increase reuse?
Solution: assign responsibilities so that coupling (dependency between classes) stays low. Choose the design with fewer dependencies.
Example: if Register creates the Payment and passes it to Sale, then Register is coupled to both Sale and Payment. If Sale creates the Payment itself, Register does not need to know Payment, so there is one less dependency and the coupling is lower.
Benefit: classes are independent, and easier to understand, change and reuse.

✓ Answer checked by Claude Sonnet 5.5

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