10.2.13.2. Use a Proxy in an Injection
Overview
A proxy is used for injection when the lifecycles of the beans are different from each other. The proxy is a subclass of the bean that is created at run-time, and overrides all the non-private methods of the bean class. The proxy forwards the invocation onto the actual bean instance.
In this example, the
PaymentProcessor instance is not injected directly into Shop. Instead, a proxy is injected, and when the processPayment() method is called, the proxy looks up the current PaymentProcessor bean instance and calls the processPayment() method on it.
Example 10.21. Proxy Injection
@ConversationScoped
class PaymentProcessor
{
public void processPayment(int amount)
{
System.out.println("I'm taking $" + amount);
}
}
@ApplicationScoped
public class Shop
{
@Inject
PaymentProcessor paymentProcessor;
public void buyStuff()
{
paymentProcessor.processPayment(100);
}
}
Fore more information about proxies, including which types of classes can be proxied, refer to Section 10.2.13.1, “About Bean Proxies”.
