JSF2: How are the *.taglib.xml files discovered in jsf-impl.jar?

问题

In jsf-impl.jar (which can be found on mvnrepository.com), the *.taglib.xml files are located in directory com/sun/faces/metadata/taglib/.

I don't understand how they're discovered in this case, because chapter 10.3.2 of the JSF 2 specification says:

10.3.2 Facelet Tag Library mechanism

...

The run time must support two modes of discovery for Facelet tag library descriptors

Via declaration in the web.xml, as specified in Section 11.1.3 “Application Configuration Parameters”

Via auto discovery by placing the tag library descriptor file within a jar on the web application classpath, naming the file so that it ends with “.taglib.xml”, without the quotes, and placing the file in the META-INF directory in the jar file.

...

Here, they're not located in directory META-INF, so how does it work?

Note: in META-INF, they are some .tld files, but I'm not interested in them since I'm not using JSP as the view, but Facelets.

回答1:

It isn't using the taglib.xml for that. It's programmatically registering them via com.sun.faces.facelets.tag.jsf.html.HtmlLibrary in com.sun.faces.application.ApplicationAssociate which is executed during startup. Here are the relevant lines from Mojarra 2.2.1 (copypasted from Grepcode):

954        c.addTagLibrary(new CoreLibrary());
955        c.addTagLibrary(new CoreLibrary(CoreLibrary.XMLNSNamespace));
956        c.addTagLibrary(new HtmlLibrary());
957        c.addTagLibrary(new HtmlLibrary(HtmlLibrary.XMLNSNamespace));
958        c.addTagLibrary(new UILibrary());
959        c.addTagLibrary(new UILibrary(UILibrary.XMLNSNamespace));
960        c.addTagLibrary(new JstlCoreLibrary());
961        c.addTagLibrary(new JstlCoreLibrary(JstlCoreLibrary.IncorrectNamespace));
962        c.addTagLibrary(new JstlCoreLibrary(JstlCoreLibrary.XMLNSNamespace));
963        c.addTagLibrary(new PassThroughAttributeLibrary());
964        c.addTagLibrary(new PassThroughElementLibrary());
965        c.addTagLibrary(new FunctionLibrary(JstlFunction.class, FunctionLibrary.Namespace));
966        c.addTagLibrary(new FunctionLibrary(JstlFunction.class, FunctionLibrary.XMLNSNamespace));
967        if (isDevModeEnabled()) {
968            c.addTagLibrary(new FunctionLibrary(DevTools.class, DevTools.Namespace));
969            c.addTagLibrary(new FunctionLibrary(DevTools.class, DevTools.NewNamespace));
970        }
971        c.addTagLibrary(new CompositeLibrary());
972        c.addTagLibrary(new CompositeLibrary(CompositeLibrary.XMLNSNamespace));

来源：https://stackoverflow.com/questions/19027595/jsf2-how-are-the-taglib-xml-files-discovered-in-jsf-impl-jar

标签

jsf-2

facelets

taglib