custom tag attribute validation

[david allen]

Hi all,

I am writing a custom tag and one of the attributes is a string. For this attribute I want the user the user to enter one of 5 possible values.

I wanted to know the best way of validating this attribute to make sure the user has added on of the possible 5 values.

What is the best way of doing this?

Thank you

David

[Eugene Lucash]

If user means end user and attribute value will be dynamic, you must validate it for yourself.
If user means developer who will use this tag, you can use special api.
search google for TLV (tag library validation)

[ramprasad madathil]

If you are writing a tag used by other developers and you want to validate the value of the attribute, then you may consider using TagExtraInfo (tei) classes. You could override the isValid() method to return true/false. A TagData object is passed to this method which contains the attribute values. This works at translation time and hence if your attribute supports runtime translation (rtexpr value = true), this will not work.

Here are links to some resources
1. http://today.java.net/pub/a/today/2004/02/04/validation.html
2. http://www.onjava.com/pub/a/onjava/2001/01/18/jsptags.html?page=last

ram.