Unpackaged Tag Files

Tag files placed in a subdirectory of /WEB-INF/tags/ do not require a TLD file and don’t have to be packaged. Thus, to create reusable JSP code, you simply create a new tag file and place the code inside it.

The web container generates an implicit tag library for each directory under and including /WEB-INF/tags/. There are no special relationships between subdirectories; they are allowed simply for organizational purposes. For example, the following web application contains three tag libraries:

/WEB-INF/tags/
/WEB-INF/tags/a.tag
/WEB-INF/tags/b.tag
/WEB-INF/tags/foo/
/WEB-INF/tags/foo/c.tag
/WEB-INF/tags/bar/baz/
/WEB-INF/tags/bar/baz/d.tag

The implicit TLD for each library has the following values:

• tlib-version for the tag library. Defaults to 1.0.

• short-name is derived from the directory name. If the directory is /WEB-INF/tags/, the short name is simply tags. Otherwise, the full directory path (relative to the web application) is taken, minus the /WEB-INF/tags/ prefix. Then all / characters are replaced with - (hyphen), which yields the short name. Note that short names are not guaranteed to be unique.

• A tag-file element is considered to exist for each tag file, with the following subelements:

  • The name for each is the filename of the tag file, without the .tag extension.

  • The path for each is the path of the tag file, relative to the root of the web application.

So, for the example, the implicit TLD for the /WEB-INF/tags/bar/baz/ directory would be as follows:

<taglib>
    <tlib-version>1.0</tlib-version>
    <short-name>bar-baz</short-name>
    <tag-file>
        <name>d</name>
        <path>/WEB-INF/tags/bar/baz/d.tag</path>
    </tag-file>
</taglib>

Despite the existence of an implicit tag library, a TLD in the web application can still create additional tags from the same tag files. To accomplish this, you add a tag-file element with a path that points to the tag file.