Lifecycle support

From [e-mail] on March 14, 2007 09:22:31

Support for JSR-250 (javax.annotation) would also be very useful for all those people using init() methods and the list.

The mapping I think is:

@PostConstruct -> Called right after construction @Resource -> Analogous to @Inject @PreDestroy -> No concept of destruction, is there? @Generated -> Doesn’t apply

_Original issue: http://code.google.com/p/google-guice/issues/detail?id=62_

[sameb]

We have no plans of implementing lifecycle support.

You can use Guava’s Service + ServiceManager(https://github.com/google/guava/wiki/ServiceExplained) to have services with a lifecycle. The simplest way is to bind a multiset of Set<Service> and construct a ServiceManager with that set.

For things where you want to do something after creation/injection (otherwise known as provisioning), you can use a ProvisionListener (http://google.github.io/guice/api-docs/latest/javadoc/index.html?com/google/inject/spi/ProvisionListener.html, bound with Binder.bindListener).

Guice has no concept of “finishing” a scope or object, so anything where you want to do something on-destroy must be done through a separate framework that’s better suited to lifecycle management.

[gissuebot]

From crazyboblee on March 15, 2007 14:03:26

I’m inclined to lean on garbage collection for finalization logic. Or to delegate responsibility to something like OSGi.

We really need an external post-injection/pre-scoping hook. Then you could do whatever you want in a generic fashion:

1. Call an init() method or some annotated method.
2. Create a phantom reference to an object so you can close its resources before garbage collection when the scope goes away.
3. Peform ad hoc injections. For example, Struts calls setters on interceptors with parameters from the config file.

Maybe something like this:

interface ProviderInterceptor<T> {   T intercept(Key<T> key, Provider<T> next);   }

Then you could apply them like this:

void bindInterceptor(Matcher<Key<…>> keyMatcher, ProviderInterceptor<…> interceptor);