Thanks alot Mac,
A very good thread.
Bill
Mac Ferguson wrote:
>Actually, release() is only guaranteed to be called before the handler is
>GC'ed (JSP1.2 specification p.166), and is intended to release any
>heavyweight resources the handler may have acquired. Also from page 165
>(describing the )"[1]this transition is intended to be for releasing
>long-term data. no guarantees are assumed on whether any properties have
>been retained or not." Here's a link to a discussion on the taglibs-dev
>maillist that was very educational for me...
>http://www.mail-archive.com/taglibs-dev@jakarta.apache.org/msg00846.html
>
>
>-----Original Message-----
>From: Bill Clinton [mailto:[EMAIL PROTECTED]]
>Sent: Wednesday, September 05, 2001 7:29 PM
>To: [EMAIL PROTECTED]
>Subject: Re: Concurrency and Custom JSP tags
>
>
>Erik -
> Thanks for clearing that up. I will be sure to recheck my release
>methods. It is a relief to know that there is nothing to worry about
>here (as long as the resources are cleared).
>
>Thanks,
>Bill
>
>Erik Hatcher wrote:
>
>>Quoting from Geary's Advanced JavaServer Pages book, p. 14:
>>
>>"Because servlet containers can reuse tag handlers, you must be diligent
>>about implementing the release method and careful about instantiating
>>resources in doStartTag [rather in the tags constructor]"
>>
>>So the 'release' method is the key. You'll notice that the Struts tags
>>
>use
>
>>the release method to clear their resources. Tag instances are not used
>>simultaneously, but released for re-use after they are done, so member
>>variables are ok, but care must be taken not to allow them to carry over to
>>future uses.
>>
>>I highly recommend Geary's book for all Struts power users and developers,
>>especially in regards to custom tag development.
>>
>> Erik
>>
>>
>>----- Original Message -----
>>From: "Bill Clinton" <[EMAIL PROTECTED]>
>>To: "struts" <[EMAIL PROTECTED]>
>>Sent: Wednesday, September 05, 2001 3:42 PM
>>Subject: Concurrency and Custom JSP tags
>>
>>
>>>Hello,
>>> I have been writing my own custom jsp tags, and have recently
>>>noticed that member properties of tags seem to be retained after the tag
>>>is complete.
>>>
>>> For example, lets say you have a tag that has an optional attribute
>>>called "message", and the tag is designed to print this attribute if it
>>>is passed. If you call this tag and pass "hello" as the attribute
>>>message on one page, then call this tag on another page without passing
>>>the attribute, it will still be set to "hello".
>>>
>>> This functions much like a servlet, which is multi-threaded but
>>>retains the values for member variables across different requests. I
>>>think most servlet programmers realize this and stay away from using
>>>non-static member variables. But it seems to me that custom JSP tag
>>>design encourages the use of attributes, which seems to be potentially
>>>very dangerous in an environment with a high volume of requests.
>>>
>>> I would like to know if anyone knows of any good links where
>>>concurrency issues in custom jsp tags are discussed more in depth.
>>>Also, I am curious to know if anyone has encountered any problems like
>>>this with the Struts tags. For example, if I set an "onmouseover" for a
>>><html:checkbox> tag, do I have to worry about this attribute showing up
>>>in a <html:checkbox> tag called from a different page if both pages are
>>>loaded by different users at the same time?
>>>
>>>Thanks in advance for any info,
>>>Bill
>>>
>>
>>.
>>
>
>
>
>
>.
>
