Create JSF xhtml View (OnFly) from database [duplicate] - jsf

Question

I am able to successfully get this to work with the template in my app:
<ui:decorate template="/WEB-INF/templates/mytemplate.xhtml">
I am also able to move template to /META-INF/templates/mytemplate.xhtml of a JAR and get this to work:
<ui:decorate template="/templates/mytemplate.xhtml">
I would actually like to put this file onto filesystem (or database for that matter). How can I achieve this? I found plenty of things related to com.sun.facelets.impl.DefaultResourceResolver, but I don't think that is actually related to override the serving of the template. It is not trying resolve a URL, it is simply trying to get the file somehow on the classpath.

Answer 1

If you're already on JSF 2.2, you can do this by providing a custom ResourceHandler wherein you return the desired view resource in createViewResource().
public class FaceletsResourceHandler extends ResourceHandlerWrapper {
private ResourceHandler wrapped;
public FaceletsResourceHandler(ResourceHandler wrapped) {
this.wrapped = wrapped;
}
#Override
public ViewResource createViewResource(FacesContext context, final String name) {
ViewResource resource = super.createViewResource(context, name);
if (resource == null) {
resource = new ViewResource() {
#Override
public URL getURL() {
try {
return new File("/some/base/path", name).toURI().toURL();
} catch (MalformedURLException e) {
throw new FacesException(e);
}
}
};
}
return resource;
}
#Override
public ResourceHandler getWrapped() {
return wrapped;
}
}
Which is registered in faces-config.xml as below:
<application>
<resource-handler>com.example.FaceletsResourceHandler</resource-handler>
</application>
Or if you're not on JSF 2.2 yet, then use ResourceResolver instead.
public class FaceletsResourceResolver extends ResourceResolver {
private ResourceResolver parent;
public FaceletsResourceResolver(ResourceResolver parent) {
this.parent = parent;
}
#Override
public URL resolveUrl(String path) {
URL url = parent.resolveUrl(path); // Resolves from WAR.
if (url == null) {
try {
url = new File("/some/base/path", path).toURI().toURL();
} catch (MalformedURLException e) {
throw new FacesException(e);
}
}
return url;
}
}
Which is registered in web.xml as below:
<context-param>
<param-name>javax.faces.FACELETS_RESOURCE_RESOLVER</param-name>
<param-value>com.example.FaceletsResourceResolver</param-value>
</context-param>
Regardless of the way, in order to provide the resource from the database, you'd either save/cache them on (temp) disk file system so you can provide the URL just via File, or invent a custom protocol such as db:// and provide a custom URLStreamHandlerFactory and URLStreamHandler implementation to perform the actual job of streaming from the DB. You can find a kickoff example here Registering and using a custom java.net.URL protocol.