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14.5 Optionally Including the Tag Body

329

Figure 14 4 The custom csajsp:heading element gives you much more control 

over heading format than does the standard H1 through H6 elements in HTML.

14.5 Optionally Including the Tag 

Body

Most tags either never make use of body content or always do so. This sec 

tion shows you how to use request time information to decide whether or not

to include the tag body. Although the body can contain JSP that is interpreted

at page translation time, the result of that translation is servlet code that can

be invoked or ignored at request time.

The Tag Handler Class

Optionally including the tag body is a trivial exercise: just return

EVAL_BODY_INCLUDE

 or 

SKIP_BODY

 depending on the value of some

request time expression. The important thing to know is how to discover

that request time information, since 

doStartTag

 does not have 

Http 

ServletRequest

 and 

HttpServletResponse

 arguments as do 

service

,

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