The Java EE 5 Tutorial (PDF) - Oracle Software Downloads

Defining the Custom ComponentTag in aTag Library Descriptor
If your component does not have a renderer associated with it, getRendererType should return
null. In this case, the renderer-type element in the application configuration file should also
be set to null.
Releasing Resources
It’s recommended practice that all tag handlers implement a release method, which releases
resources allocated during the execution of the tag handler. The release method of MapTag as
follows:
public void release() {
super.release();
current = null;
styleClass = null;
actionListener = null;
immediate = null;
action = null;
}
This method first calls the UIComponentTag.release method to release resources associated
with UIComponentTag. Next, the method sets all attribute values to null.
Defining the Custom ComponentTag in aTag Library
Descriptor
432
To define a tag, you declare it in a TLD. The web container uses the TLD to validate the tag. 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. The bookstore.tld file defines
tags for all the custom components and the custom validator tag described in “Creating a
Custom Tag” on page 400.
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:
map
taglib.MapTag
binding
false
The Java EE 5Tutorial • June 2010