@@ -179,6 +179,88 @@ The disadvantages of setter injection are:
179179* You cannot be sure the setter will be called and so you need to add checks
180180 that any required dependencies are injected.
181181
182+ Getter Injection
183+ ----------------
184+
185+ Another possible injection point into a class is by overriding a getter method
186+ to make it return the dependency::
187+
188+ // ...
189+ abstract class NewsletterManager
190+ {
191+ abstract protected function getMailer(): MailerInterface;
192+
193+ protected function getLogger(): LoggerInterface
194+ {
195+ return new NullLogger();
196+ }
197+
198+ // ...
199+ }
200+
201+ ..configuration-block ::
202+
203+ ..code-block ::yaml
204+
205+ services :
206+ # ...
207+
208+ app.newsletter_manager :
209+ class :AppBundle\Mail\NewsletterManager
210+ getters :
211+ getMailer :' @mailer'
212+ getLogger :' @logger'
213+
214+ code-block ::xml
215+
216+ <?xml version =" 1.0" encoding =" UTF-8"
217+ <container xmlns =" http://symfony.com/schema/dic/services"
218+ xmlns : xsi =" http://www.w3.org/2001/XMLSchema-instance"
219+ xsi : schemaLocation =" http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd"
220+
221+ <services >
222+ <!-- ...-->
223+
224+ <service id =" app.newsletter_manager" class =" AppBundle\Mail\NewsletterManager"
225+ <getter name =" getMailer" type =" service" id =" mailer"
226+ <getter name =" getLogger" type =" service" id =" logger"
227+ </service >
228+ </services >
229+ </container >
230+
231+ code-block ::php
232+
233+ use AppBundle\Mail\NewsletterManager;
234+ use Symfony\Component\DependencyInjection\Definition;
235+ use Symfony\Component\DependencyInjection\Reference;
236+
237+ // ...
238+ $container->register('app.newsletter_manager', NewsletterManager::class)
239+ ->addOverriddenGetter('getMailer', new Reference('mailer'))
240+ ->addOverriddenGetter('getLogger', new Reference('logger'))
241+ ;
242+
243+
244+
245+ * The dependency can be created lazily - ie only when it is actually needed.
246+
247+ * It works well with both optional and required dependencies: either provide
248+ a default implementation for optional ones, or make the getter abstract for
249+ required ones.
250+
251+ * You can be sure that the dependency will not change during the object's
252+ lifetime.
253+
254+ * It works well with class hierarchies since you can also override getters of
255+ parent classes.
256+
257+ The disadvantages of getter injection are:
258+
259+ * You must call the getter everytime you need the dependency internally.
260+
261+ * By using inheritance to override methods, it doesn't work with final classes
262+ and requires such getters to be made protected or public.
263+
182264Property Injection
183265------------------
184266