Defining the Custom Component Tag in a Tag Library Descriptor

Defining the Custom Component Tag in a Tag Library Descriptor

To define a tag, you declare it in a tag library descriptor, which is an XML document that describes a tag library. A TLD contains information about a library and each tag contained in the library. TLDs are used by a Web container to validate the tags. The set of tags that are part of the HTML render kit are defined in the html_basic TLD.

The custom tags area and map are defined in bookstore.tld, which is stored in the <INSTALL>/j2eetutorial14/examples/web/bookstore6/src/taglib/ directory. The bookstore6/web/bookstore.tld defines tags for all the custom components included in this release.

All tag definitions must be nested inside the taglib element in the TLD. Each tag is defined by a tag element. Here is part of the tag definition of the map tag:
<tag>
  <name>map</name>
  <tag-class>taglib.MapTag</tag-class>
  <attribute>
    <name>binding</name>
    <required>false</required>
    <rtexprvalue>false</rtexprvalue>
  </attribute>
  <attribute>
    <name>current</name>
    <required>false</required>
    <rtexprvalue>false</rtexprvalue>
  </attribute>
  <attribute>
    <name>id</name>
    <required>false</required>
    <rtexprvalue>false</rtexprvalue>
  </attribute>
  ...
</tag> 
At a minimum, each tag must have a name (the name of the tag) and a tag-class (the tag handler) attribute. For more information on defining tags in a TLD, please consult the Tag Library Descriptors section of this tutorial.

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