Question

How to ensure maintainability in a class? Can it simply be done by creating class using design patterns or is there something else involved? Also, what are the characteristics of a good method?

Answer 1

You won’t do badly by following the SOLID and DRY principles.

SOLID is:

SRP Single responsibility principle
the notion that an object should have only a single responsibility.

OCP
Open/closed principle
the notion that “software entities … should be open for extension, but closed for modification”.

LSP
Liskov substitution principle
the notion that “objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program”. See also design by contract.

ISP
Interface segregation principle
the notion that “many client specific interfaces are better than one general purpose interface.”[5]

DIP
Dependency inversion principle
the notion that one should “Depend upon Abstractions. Do not depend upon concretions.”[5]
Dependency injection is one method of following this principle.

And DRY stands for Don’t Repeat Yourself, meaning you should strive to remove any duplication in your code.