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https://issues.apache.org/jira/browse/SHINDIG-1225?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12779377#action_12779377
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Mikhail Kotelnikov edited comment on SHINDIG-1225 at 11/18/09 9:29 AM:
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The problem is that by default the OSGi environment does not support war files.
The OSGi spec defines just the org.osgi.service.http.HttpService interface
which used to register servlets and resources. That is all. In classical web
applications (packaged as wars) Guice Injectors are stored in ServletContexts
which are configured via web.xml files. In the OSGi environment we don't have
direct access to the ServletContext - it is created under the hood by the
HttpService implementation. But we could define our own
org.osgi.service.http.HttpContext instance (it is an another interface defined
by the OSGi spec). The specification guaranties us that all servlets registered
with the same instance of HttpContext share the same ServletContext (created
under the hood, as I said).
So we are using this feature of OSGi in the following way:
* We create our own HttpContext. All servlets registered with this HttpContext
will share the same ServletContext.
* We create and register a fake servlet with this HttpContext *before* all
other Shindig servlets. The "init(ServletConfig)" method of this servlet just
creates a new Guice injector, configures it and sets in the ServletContext
(already available in the init(ServletConfig) method via
ServletConfig#getServletContext()).
* When the first fake servet finish his job in the init(ServletConfig) method
we can register all other Shindig servlets. They have already access to the
configured Guice Injector in the previous step.
As you can see this registration of a fake servlet is required to make all
stuff working. So we (unfortunately) need this URL path mapping - otherwise we
could not register this servlet in the HttpService.
- Mikhail
was (Author: mkotelnikov):
The problem is that by default the OSGi environment does not support war
files. The OSGi spec defines just the org.osgi.service.http.HttpService
interface which used to register servlets and resources. That is all. In
classical web applications (packaged as wars) Guice Injectors are stored in
ServletContexts which are configured via web.xml files. In the OSGi environment
we don't have direct access to the ServletContext - it is created under the
hood by the HttpService implementation. But we could define our own
org.osgi.service.http.HttpContext instance (it is an another interface defined
by the OSGi spec). The specification guaranties us that all servlets registered
with the same instance of HttpContext share the same ServletContext (created
under the hood, as I said).
So we are using this feature of OSGi in the following way:
* We create our own HttpContext. All servlets registered with this HttpContext
will share the same ServletContext.
* We create and register a fake servlet with this HttpContext *before* all
other Shindig servlets. The init(ServletContext) method of this servlet just
creates a new Guice injector, configures it and sets in the ServletContext
(already available in the init(ServletContext) method).
* When the first fake servet finish his job in the init(ServletContext) method
we can register all other Shindig servlets. They have already access to the
configured Guice Injector in the previous step.
As you can see this registration of a fake servlet is required to make all
stuff working. So we (unfortunately) need this URL path mapping - otherwise we
could not register this servlet in the HttpService.
- Mikhail
> Make Shindig jars available as OSGi bundles
> -------------------------------------------
>
> Key: SHINDIG-1225
> URL: https://issues.apache.org/jira/browse/SHINDIG-1225
> Project: Shindig
> Issue Type: Improvement
> Components: Java
> Reporter: David Johnson
> Attachments: ShindigActivator.java
>
>
> Make changes to the Shindig-Java build process so that the Shindig Jars are
> each available as OSGi bundles.
> See also:
> November 2009 thread: Shindig and OSGi
> http://markmail.org/thread/hrozofu6mkyj3bm4
> May 2009 thread: Shindig as an OSGi Bundle
> http://markmail.org/thread/fqechw5ek7uxnehw
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