Setterinjektálás

Setterinjektálás is a programming technique used in object-oriented programming, particularly in languages like Java and C#. It is a specific type of dependency injection where the dependencies of a class are provided through setter methods rather than through the constructor.

In setter injection, a class has public setter methods, such as `setDependency(DependencyType dependency)`, which are used to inject the required objects or services. These setter methods are typically called after the object itself has been instantiated. This approach differs from constructor injection, where dependencies are passed as arguments to the class's constructor.

The primary advantage of setter injection is its flexibility. It allows dependencies to be optional or to be changed after the object has been created. This can be useful in scenarios where a dependency might not always be available or when certain configurations need to be applied dynamically. It can also help to reduce the complexity of constructors when a class has a large number of dependencies.

However, setter injection can also lead to certain drawbacks. If a dependency is mandatory for the object to function correctly, there is a risk that the setter method might not be called, leading to runtime errors. To mitigate this, developers often employ techniques like ensuring that essential dependencies are injected via the constructor and optional ones via setters. Frameworks that support dependency injection often provide mechanisms to manage and enforce the injection of dependencies, whether through constructors or setters.