Luis Cornide Arce wrote:
> Hi List!!
>
> I'm developing some tags to internationalize my JSP pages (yes, I know
> that Struts has done that already, but I'm trying to do it by my own)
> I have one tag to retrieve a message by specifiying its key, and inside
> of this tag I can write other to parametrize the message (doing a
> substitution of a pattern by the value given), an example
> <mytag:AppMessage id='index.welcome'>
> <mytag:Param value='Hi world' />
> </mytag:AppMessage>
>
> My problem is that the inner tag is completely ignored. The class that
> implements the tag AppMessage extends BodyTagSupport and the methos
> doStartTag() returns EVAL_BODY_BUFFERED, is this correct? anybody knows
> what can be the error?
>
> Thanks in advance,
Implementing the BodyTag interface and returning EVAL_BODY_BUFFERED is
onlye needed for a tag handler that *reads* its body. In the example
above, all you want is to *evaluate* the body, so you only need to
implement the Tag interface (e.g. by extending TagSupport) and return
EVAL_BODY_INCLUDE from doStartTag() in your AppMessage tag handler. This
tells the container to invoke the Param tag handler for the nested action.
In the Param tag handler, you must locate the AppMessage tag handler
parent, using TagSupport.findAncestorWithClass(), and call a public
method on the parent to pass it the parameter value. Assuming the
method is called addParameter(), the Param tag handler looks something
like this:
public class ParamTag extends TagSupport {
private String value;
public void setValue(String value) {
this.value = value;
}
public int doEndTag() throws JspException {
AppMessageTag parent = (AppMessageTag)
findAncestorWithClass(this, AppMessageTag.class);
if (parent == null) {
throw new JspException("The param action is not " +
"enclosed by a supported action type");
}
parent.addParameter(value);
return EVAL_PAGE;
}
}
In the AppMessage tag handler, this method adds the value to some
sort of collection (e.g. a List), and is used in the doEndTag()
method to parameterize the message. You must also make sure you
remove all values between invokations, since the tag handler may
be reused for other occurances of the action element. A good place
to do this is in the doStartTag() method.
I hope this helps,
Hans
--
Hans Bergsten [EMAIL PROTECTED]
Gefion Software http://www.gefionsoftware.com
JavaServer Pages http://TheJSPBook.com
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