SOLID (Single responsibility, Open-closed, Liskov substitution, Interface segregation and Dependency inversion) is a mnemonic acronym that stands for five basic principles of object-oriented programming and design. The principles, when applied together, intend to make it more likely that a programmer will create a system that is easy to maintain and extend over time. The principles of SOLID are guidelines that can be applied while working on software to remove code smells by causing the programmer to refactor the software's source code until it is both legible and extensible. It is part of an overall strategy of agile and adaptive programming.
Single responsibility principle
a class should have only a single responsibility (i.e. only one potential change in the software's specification should be able to affect the specification of the class)
Open/closed principle
software entities should be open for extension, but closed for modification.
Liskov substitution principle
objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program.
Interface segregation principle
many client-specific interfaces are better than one general-purpose interface.
Dependency inversion principle
Depend upon Abstractions. Do not depend upon concretions. Dependency injection is one method of following this principle.
Single responsibility principle
a class should have only a single responsibility (i.e. only one potential change in the software's specification should be able to affect the specification of the class)
Open/closed principle
software entities should be open for extension, but closed for modification.
Liskov substitution principle
objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program.
Interface segregation principle
many client-specific interfaces are better than one general-purpose interface.
Dependency inversion principle
Depend upon Abstractions. Do not depend upon concretions. Dependency injection is one method of following this principle.