Does using a decorator class imply dependency injection in code?

Using a decorator does not automatically imply dependency injection, but the two concepts can be combined. A decorator is a structural pattern that wraps an object to extend its behavior. Dependency injection (DI) is a technique for supplying an object’s dependencies from the outside, usually via constructor, setter, or interface injection. When you create a decorator, you typically pass the object it decorates as a constructor argument, which is a form of DI because the decorator receives its dependency externally. However, DI is broader: it can inject services, configuration, or other collaborators, not just the wrapped object. Therefore, while a decorator often uses DI to obtain the component it decorates, the presence of a decorator alone does not guarantee that the codebase employs a full DI framework or pattern.