How can I create a clean tag library (.jar) containing custom tags and composite components in JSF 2.2?

Question

I've read the various blog posts and stackoverflow posts on how to create a composite components and custom tags within a web app and have gotten things to work just fine. I'm now trying to move everything into a reusable JAR file.

mylib.jar hierarchy:

src/main/java
    com.example.MyComposite.java
src/main/resources/
    META-INF
        faces-config.xml
        my.taglib.xml
    META-INF/resources/components
        myComposite.xhtml
    META-INF/tags
        myTag.xhtml

my.taglib.xml:

<facelet-taglib version="2.2"
            xmlns="http://xmlns.jcp.org/xml/ns/javaee"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-facelettaglibrary_2_2.xsd">

    <namespace>http://www.example.com/components</namespace>

    <tag>
        <tag-name>myTag</tag-name>
        <source>
                tags/myTag.xhtml
        </source>
    </tag>

    <tag>
        <tag-name>myComposite</tag-name>
        <component>
            <resource-id>
                components/myComposite.xhtml
            </resource-id>
        </component>
    </tag>
</facelet-taglib>

I've built this as a jar and used it in my web-app and both the custom tag and composite component work great. It took me trying 100 different combinations of hierarchy to get it to work though.

My problem is that I don't like how I seem to have to put custom tags in one place (/tags) and composite components in another (/resources/components). In addition, I have to reference custom tags with the source tag and composite components with a component/resource-id tag. For example, I tried putting the myTag.xhtml into /resources/components and referencing it with a resource-id but I got NPE's when I tried to use it.

So do tags and components have to be in different directories? Do I just have to live with this hierarchy?

Generator

I take it that your custom tags are those classes typically derived from UIComponent, UIOutput etc.? Then the answer is yes. As far as I know there's no way to define both custom components and composite components in a common namespace. – Coed

@StephanRauh: it are just tagfiles. <tag><source>, not <tag><component>. See also #6822500 – Hebraize

Interesting - I didn't know this feature of JSF. But while we're at it: does your <composite-library-name> trick allow us to put composite components and custom components into the same namespace? – Coed

They're indeed undervalued (and composites are overvalued). And yes, they will end up in same namespace. See also the answer's "See also" link. – Hebraize

Answer 1

You can use <composite-library-name> alone for composites to reduce unnecessary <tag> boilerplate for composites. As to tagfiles, you could just put them in /resources/tags and alter <source> accordingly so the folder structure is more uniform.

src/main/java
 `-- com/example/MyComposite.java

src/main/resources
 `-- META-INF
      |-- resources
      |    |-- components
      |    |    `-- myComposite.xhtml
      |    `-- tags
      |         `-- myTag.xhtml
      |-- faces-config.xml
      `-- my.taglib.xml

<facelet-taglib version="2.2"
            xmlns="http://xmlns.jcp.org/xml/ns/javaee"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-facelettaglibrary_2_2.xsd">

    <namespace>http://www.example.com/components</namespace>
    <composite-library-name>components</composite-library-name>

    <tag>
        <tag-name>myTag</tag-name>
        <source>resources/tags/myTag.xhtml</source>
    </tag>
</facelet-taglib>

See also:

• Change composite-component's namespace

Hebraize

Wow, I really like that composite-library-name shortcut. Saves a lot of XML. Too bad there isn't a tag-library-name tag to make it even easier for tags. Still, this is better than what I'm using so thanks (on vacation this week but will test this when I get back) – Generator

I agree that we should make developing tagfiles easier by introducing more conventions/implicitness which should further reduce XML. Composites are too much abused over tagfiles for exactly this reason. – Hebraize