Is there a way to close/destruct object in guice 4?

[klc]

Hi Is there a way to destruct object in guice 4?

I see guice fruit but i think it support guice 2. The object i'm closing are db, queue and etc.

[Stephan Classen]

Yes, but you have to be more specific if you want some concrete help

[klc]

Sorry

What i have now is a provider of let say a queue (Singleton scope). If the queue has been created, i will get from the injector and close it. (or is there a way to do this automatically?)

This is on guice-servlet.

klc

[klc]

So my questions are:

1. Is there a way to find out if a guice has been created?

2. Is there a way to let guice to run deconstruct when server is closing? (ie ServletContextListener.contextDestroyed)

klc

[Stuart McCulloch]

On Thursday, 14 May 2015 at 10:50, klc wrote:

So my questions are:

1. Is there a way to find out if a guice has been created?

Previously in Guice 3 you could use a TypeListener to track when objects were directly instantiated by Guice (this doesn’t cover objects constructed inside of providers):

http://google.github.io/guice/api-docs/latest/javadoc/com/google/inject/Binder.html#bindListener-com.google.inject.matcher.Matcher-com.google.inject.spi.TypeListener-

In Guice 4 you can also use the new ProvisionListener API to track when objects are provisioned (ie. either instantiated by Guice itself or returned from a provider)

http://google.github.io/guice/api-docs/latest/javadoc/com/google/inject/Binder.html#bindListener-com.google.inject.matcher.Matcher-com.google.inject.spi.ProvisionListener...-

but you might have to do some de-duplication here since the same object could be provisioned multiple times.

Another approach is to use a custom scope to record object use - you can then add a close method to the scope and call it when you want to dispose of those objects:

https://github.com/google/guice/wiki/CustomScopes

2. Is there a way to let guice to run deconstruct when server is closing? (ie ServletContextListener.contextDestroyed)

Assuming you’ve got a record of the objects needing to be destroyed (using one of the methods above) then it’s mainly a matter of going through the list in reverse order and calling the right destroy method.

klc

On Thursday, May 14, 2015 at 5:34:02 PM UTC+8, klc wrote:

Sorry

What i have now is a provider of let say a queue (Singleton scope). If the queue has been created, i will get from the injector and close it. (or is there a way to do this automatically?)

This is on guice-servlet.

klc

On Thursday, May 14, 2015 at 5:31:20 PM UTC+8, scl wrote:

Yes, but you have to be more specific if you want some concrete help

Am 14. Mai 2015 11:25:52 MESZ, schrieb klc <klchan...@gmail.com>:

Hi Is there a way to destruct object in guice 4?

I see guice fruit but i think it support guice 2. The object i'm closing are db, queue and etc.

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[Vyacheslav Rusakov]

If you just want spring-like @PostConstruct and @PreDestroy methods support then there are many libs that implements it like https://github.com/mycila/guice, https://github.com/Netflix/governator etc.

I even wrote my own https://github.com/xvik/guice-ext-annotations.

But, such things are against guice philosophy: https://github.com/google/guice/wiki/ModulesShouldBeFastAndSideEffectFree

In short, you should avoid implicit bootstrap logic and do some special lifecycle service with start/stop methods which should be called from outside world.

For example, in web application it could be servlet context listener which will call start / stop.

четверг, 14 мая 2015 г., 15:50:16 UTC+6 пользователь klc написал: