Provide a mechanism for adding ApplicationContextInitializers to DispatcherServlet's ApplicationContext [SPR-11314]

[spring-projects-issues]

nebhale opened SPR-11314 and commented

Currently, there is no way to add an ApplicationContextInitializer to the DispatcherServlet's ApplicationContext at runtime (i.e. without explicit configuration on the application's part). This is possible to do on the root ApplicationContext using the contextInitializerClasses Servlet init-param.

Some mechanism (accessible from a ServletContainerInitializer) should be exposed in order to influence the DispatcherServlet's ApplicationContext and allow an ApplicationContextInitializer to be added.

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Affects: 3.2.6, 4.0 GA

Reference URL: https://github.com/nebhale/spring-servlet3-autoreconfig-poc

Referenced from: commits 444b372, 5fb2665, 91881ff

Backported to: 3.2.7

[spring-projects-issues]

Glyn Normington commented

For anyone who didn't dig into the reference URL, the goal of this feature is to support auto-reconfiguration for servlet 3 applications.

[spring-projects-issues]

Juergen Hoeller commented

I've implemented this as a "globalInitializerClasses" init-param now, basically like the existing "contextInitializerClasses" but applying to FrameworkServlets as well. They are applied right at the end of context initialization but still before locally specified "contextInitializerClasses", if any, to preserve a remaining chance for overriding.

Since this implementation is rather straightforward, I'm backporting it to 3.2.7 as well. Can't remember whether you ever asked for it, but here you go :-)

Juergen

[spring-projects-issues]

Juergen Hoeller commented

Guys, please test this over the next few days against the latest snapshots.

Would be great to have it verified to work with both 4.0.1 and 3.2.7 before that pair gets released on Jan 23...

Juergen

[spring-projects-issues]

nebhale commented

Juergen Hoeller, is this a replacement for the contextInitializerClasses init-param, or in addition to it?

[spring-projects-issues]

Juergen Hoeller commented

This is in addition to the regular contextInitializerClasses value; both settings are evaluated. However, I wouldn't expect much mixing-and-matching there.

Juergen

[spring-projects-issues]

nebhale commented

Juergen Hoeller I've tried the latest snapshot (4.0.1.BUILD-20140116.115106-72) and it doesn't seem to be working. I've added the support as:

ctx.setInitParameter(ContextLoader.CONTEXT_INITIALIZER_CLASSES_PARAM,
        AutoReconfigurationApplicationContextInitializer.class.getCanonicalName());
ctx.setInitParameter(ContextLoader.GLOBAL_INITIALIZER_CLASSES_PARAM,
        AutoReconfigurationApplicationContextInitializer.class.getCanonicalName());

I still see the root context doing the right thing, but no change to the FrameworkServlet ApplicationContext.

[spring-projects-issues]

Juergen Hoeller commented

Hmm, just the "globalInitializerClasses" init-param should be sufficient for all application contexts. So there's no need to set "contextInitializerClasses" in addition. Does "globalInitializerClasses" alone apply to the root context correctly, at least?

This is how we test the FrameworkServlet effect at the moment:

public void testGlobalInitializerClasses() throws Exception {
	DispatcherServlet servlet = new DispatcherServlet();
	servlet.setContextClass(SimpleWebApplicationContext.class);
	servletConfig.getServletContext().setInitParameter(ContextLoader.GLOBAL_INITIALIZER_CLASSES_PARAM,
			TestWebContextInitializer.class.getName() + "," + OtherWebContextInitializer.class.getName());
	servlet.init(servletConfig);
	assertEquals("true", servletConfig.getServletContext().getAttribute("initialized"));
	assertEquals("true", servletConfig.getServletContext().getAttribute("otherInitialized"));
}

So I'm not sure what's not working there :-(

Juergen

[spring-projects-issues]

nebhale commented

Looks like an issue on my end (I don't think IDEA replaced my original code in the Tomcat container), but it appears to work. This should be exactly what we need. Thanks for the work.

[spring-projects-issues]

Juergen Hoeller commented

Cool, good to hear :-)