Sounds good to me. I'll post a link to this discussion at the end of my old blog posting. --tim
On Tue, Feb 3, 2009 at 1:43 PM, Klotz, Leigh <[email protected]> wrote: > I am using Restlet Resource Dependency Injection in Guice/Restlet as > described in > > http://tembrel.blogspot.com/2008/07/resource-dependency-injection-in.html > > Much like the Spring integration org.restlet.ext.spring.SpringFinder, this > package provides its own Finder, via a FinderFactory. > > WadlApplication does not work when using the Finder from the Guice > integration. > > Below I explain the issue, make a suggestion to change Finder and > WadlApplication to eliminate the issue, and propose a workaround to Tim > Peierls's suggested code. > > *Explanation > *Specifically, the following line in WadlApplication fails for classes > found with the Guice Finder: > class WadlApplication { ... > private ResourceInfo getResourceInfo(Finder finder, String path, > Request request, Response response) { > // The handler instance targeted by this finder. > final Handler handler = > finder.createTarget(finder.getTargetClass(), request, response); > > As near as I can tell, in Restlet 1.1.1, that line in WadlApplication is > the only place that uses finder.createTarget(class, request, response). > > *Suggestions to change Finder and WadlApplication*: > > 1. Change WadlApplication to use finder.findTarget(request, response) instead > of finder.createTarget(class, request, response) > > 2. If there is no need for finder.createTarget(Class<? extends Handler>, > Request, Response) to be public, I would suggest that it be demoted, and > that WadlApplication be changed simple to use finder.findTarget(request, > response). > > Here is further analysis of why this fails with the Guice version, and a > workaround for Tim Peierls code suggestions. > > *Workaround for Guice Finder:* > > The Guice Finder does not implement the method createTarget(Class<? extends > Handler>, Request, Response), defaulting it to the Finder implementation. > Additionally, it does not implement getTargetClassname, because it allows > targets to be found by Guice Keys, which are more generic than classnames. > > When used from WadlApplication, finder.getTargetClass returns null, and > finder.createTarget then fails. > > I implemented a deponent version createTarget(Class<? extends Handler>, > Request, Response) which ignores Handler if null, and checks it against the > class if one is specified. > > @Override public Handler createTarget(Class<? extends Handler> > targetClass, Request request, Response response) { > if (targetClass != null && Key.get(targetClass) != key) > throw new > RuntimeException(String.format("RestletFinderFactory.createTarget > targetClass is %s but Key %s as not equal.", > targetClass, > key)); > return getInjector().getInstance(key); > } > > *Conclusion: > *I think this solution is not optimal. I believe the main issues are > raised above and would prefer to see the createTarget(class, request, > response) method deprecated and WadlApplication changed to use findTarget > instead. > > Leigh. > ------------------------------------------------------ http://restlet.tigris.org/ds/viewMessage.do?dsForumId=4447&dsMessageId=1098034
