Elegant objects in W2MO презентация

to it

Data structure usage:

Object usage:

addEdgesToGraph(Graph graph, Edge edge) {/*....*/} Edge edge(String edgeId) {/*....*/}

int save(long bytes){/*....*/} -> int bytesSaved(long bytes){/*....*/}

CommonGraphBuilder -> CommonGraphs

do not use prefixes like get-, set-

"Mutability, method names, and a complete absence of constructors are nothing compared to the much bigger sin this class is guilty of. It is not class, but rather data structure. And this sin can't be forgiven. Amen"

objects must be characterized by their capabilities. Name objects considering what they are and not what they do. "Suffix -er is evil ingredient"

be able to construct an instance of class in many different ways;
to avoid code duplication;

- Keep constructors code-free

Example: CaseTypeProduct

the very least
expose fewer then five public methods (not including constructors, private methods)
don’t use static methods
don’t use public constants

"So what we get from making classes small? The answer is elegance, maintainability, cohesiveness, and testability "

Bad example

“We shouldn’t have to know about such things as static keywords in Java, but alas, we have them. I don’t know who exactly authored them in OOP, but they are pure evil. The static methods, not the authors. I hope.”

need to have an object of class User without a name being initialized? Seriously, when and why might we have such a necessity? I think I know the answer. In most cases, this happens when we need another class, but we are to lazy to create it.”

in this book.
However, we can change it - the reality, not the book ;)

pattern that allows behavior to be added to an individual object, either statically or dynamically, without affecting the behavior of other objects from the same class.

Key use cases:
- add/remove additional functionalities/responsibilities dynamically
- avoid too much of sub-classing to add additional responsibilities.
Drawbacks:
overuse of Open Closed principle ( Open for extension and Closed for modification). Use this feature sparingly where the code is least likely changed.