Hi there,
First off i would suggest using only one custom tag insted of these two:
<input type='text'
name='<gan:getFullNameForItem name="Weight" />'
value='<gan:getValueForItem name="Weight" />' />
so that the JSP would look like:
<gan:inputfieldwriter property="Weight"/>
The reason being is that I the way you presented the problem it seems
that you're always retrieving a Key/Value pair from the HashMap and
placing it in one resulting HTML element so it makes sense to do it like
that.
Eventually you will need two tags
Gan:array
Gan:inputfieldwriter
The Gan array must allow to nest other tags in it therefore your class
must extend TagSupport.
The tag must implement the doStartTag and doEndTag methods. The doStart
will probably define your basic table element etc. it must then return
EVAL_BODY_INCLUDE to tell the Jspwriter that this tag has a body and
something must be valuated between its start and end tags. The doEndTag
method is executed when the </gan:array> element is encountered, this
will probably close the table element.
public class GanArray extends TagSupport {
public int doStartTag() throws JspException {
//Do something
return EVAL_BODY_INCLUDE;
}
public int doEndTag() throws JspException
{
//Do something
return EVAL_PAGE;
}
}
The second tag only needs to implement the doStartMethod. It will
generate the required HTML to print the input field.
public class InputFieldWirter extends BodyTagSupport {
public int doStartTag() throws JspException {
//Do something
return EVAL_BODY_TAG;
}
}
The request is of course always accessible in your taghandler by calling
the following statement:
HttpServletRequest req = (HttpServletRequest)
this.pageContext.getRequest();
Personally I would create a third (abstract) tag which would be used as
base for all standard html elements. This class would define fields
like: name, styleclass, onmouseover and all other common html
parameters. Your InputFieldWirter would then only have to extend this
tag and implement only the functionality which is specific to it. For a
good implementation check out Apache's Base Tags included in their
custom taglib.
Hope this helps
MIchael
-----Oorspronkelijk bericht-----
Van: A mailing list about Java Server Pages specification and reference
[mailto:[EMAIL PROTECTED]] Namens Cidoni_b
Verzonden: donderdag 29 augustus 2002 11:44
Aan: [EMAIL PROTECTED]
Onderwerp: Help need: Custom tags in JSP
I am trying to use custom tags in my JSP. I have illustrated the
simplified version of my problem below. Can anyone tell me how to go
about doing it?
Problem definition:
--------------------
I have a JSP in which I retrieve a hashtable from request object using
request.getAttribute() method. I need to display the commodity details
present in the Hashtable using custom tags.
Input Hashtable contents(given in Key: Value format)
---------------------------------------------------
"Commodity.length": "2"
"Commodity[0].Weight": "34"
"Commodity[1].Weight": "43"
Please note that the above keys are not Java arrays, they are just
strings
Required JSP format
-------------------
<gan:array name = "Commodity">
<table>
<tr>
<input type='text'
name='<gan:getFullNameForItem name="Weight" />'
value='<gan:getValueForItem name="Weight" />' />
</tr>
</table>
</gan:array>
Desired HTML output:
--------------------
<table>
<tr>
<input type='text'
name='Commodity[0].Weight'
value='34' />
<input type='text'
name='Commodity[1].Weight'
value='43' />
</tr>
</table>
My question:
------------
How can I go about implementing the tags starting with "gan:"?
Please note that there can be nested gan:array tags.
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