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338

Chapter 14 Creating Custom JSP Tag Libraries

Figure 14 7 The csajsp:filter element lets you insert text without worrying about 

it containing special HTML characters.

14.7 Including or Manipulating the 

Tag Body Multiple Times

Rather than just including or processing the body of the tag a single time, you

sometimes want to do so more than once. The ability to support multiple

body inclusion lets you define a variety of iteration tags that repeat JSP frag 

ments a variable number of times, repeat them until a certain condition

occurs, and so forth. This section shows you how to build such tags.

The Tag Handler Class

Tags that process the body content multiple times should start by extending

BodyTagSupport

 and implementing 

doStartTag

, 

doEndTag

, and, most

importantly, 

doAfterBody

 as before. The difference lies in the return value

of 

doAfterBody

. If this method returns 

EVAL_BODY_TAG

, the tag body is

evaluated again, resulting in a new call to 

doAfterBody

. This process contin 

ues until 

doAfterBody

 returns 

SKIP_BODY

.

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