law-of-demeter

A method should only call methods on: itself, its parameters, objects it creates, or its direct components. Never reach through an object to access another object's internals.

| Tight coupling | Caller knows internal structure | | Fragile code | Structure changes break all callers | | Hidden dependencies | Not obvious what's needed | | Hard to test | Must mock entire chain | | Null danger | Each . is a potential null |

A method m of class C should only call methods on:

Используйте при доступе к свойствам вложенных объектов. Используйте при объединении вызовов методов. Используйте при прохождении через объекты для получения данных. Источник: yanko-belov/code-craft.