Custom Tags

[Geetha Arthanari]

public class BuffTag extends BodyTagSupport
{
public int doStartTag() throws JSPException {
//insert code here.

}
}
Assume that the tag has been properly configured to allow body contents. Which, if inserted at line 12, woudl cause the
JSP code <mytags:mytag>BodyContent</mytags:mytag> to output body content?

Options:
A. return SKIP_BODY
B. return EVAL_BODY_INCLUDE
C. return EVAL_BODY_BUFFERED
D. return BODY_CONTENT

Answer is B in head first book. But i think C also correct. Can anyone explain why option B is correct and C is not correct?

[Chinmaya Chowdary]

Hi, Geeta. If EVAL_BODY_BUFFERED is return, the body of the tag is present in the BodyContent object, the container will not able to evaluate the body(that is present in the BodyContent object). The body will be evaluated only if the method has BodyContent object and if it sees the encapsulated body of it. If we override doAfterBody() with the following code,

  BodyContent bodycontent = getBodyContent();
         String body = bodycontent.getString();  

then we have the body.

If the BodyTagSupport returns EVAL_BODY_INCLUDE, no BodyContent object will be created, and the body will be evaluated.

See this , it will help you.