Hi Chris, On 19.04.2021 17:32, Christopher Schultz wrote: > > On 4/18/21 08:06, Rony G. Flatscher (Apache) wrote: >> On 11.03.2021 12:23, Rony G. Flatscher (Apache) wrote: >>> On 11.03.2021 11:53, Mark Thomas wrote: >>>> On 10/03/2021 15:14, Rony G. Flatscher (Apache) wrote: >>>>> Is there a way to know/infer that a JSP got freshly compiled from e.g. a >>>>> taglib library? >>>>> >>>>> For caching purposes it would be necessary to learn whether a JSP got >>>>> recompiled as the cache >>>>> should >>>>> be purged in that case. >>>>> >>>>> Is there a way to find out whether a JSP run is the very first after >>>>> (re-)compilation? >>>>> >>>>> Or can one rely that if a JSP gets recompiled that a new PageContext gets >>>>> created for it (or if >>>>> reused does not contain any custom attributes placed there earlier at the >>>>> PAGE_SCOPE)? >>>> Page scope gets reset at the end of a request so that won't work. >>>> >>>> It might not be perfect (containers are allowed to unload unused >>>> servlets/JSPs) but in you are >>>> using Tomcat and haven't configured maxLoadedJsps or jspIdleTimeout then >>>> you should be able to use >>>> the jspInit() method. (See JSP spec for details). >> >> It seems that the implicit JSP "page" object can probably be used to >> determine whether a JSP got >> recompiled as its hashCode() changes after recompilation. > > Something safer might be to keep a cache of datestamps keyed by JSP name (or > whatever). When the > JSP's init() method is called, you could update the datestamp. > > Or do you need to know about the recompliation before the init() is called?
The BodyTag interface [1,2] does not define an init() method, you think probably of the Servlet interface [3,4]. Ad 'page' implicit object: if the 'page' object gets referenced in the taglib, then a re-compiled version of the same JSP page is guaranteed to have a different hashCode() value and as such suffices to determine whether a page got compiled since the last time this got checked in the taglib. The motivation for learning about a (re-)fresh(ed) page is to remove any cached compiled scripts of that jsp (if it got recompiled then something got changed in the jsp, so also scripts might have changed) and from then on build a new cache. ---rony [1] javax-BodyTag with lifecycle description: <https://docs.oracle.com/javaee/7/api/javax/servlet/jsp/tagext/BodyTag.html> [2] jakarta-BodyTag: <http://tomee.apache.org/jakartaee-9.0/javadoc/jakarta/servlet/jsp/tagext/BodyTag.html#doInitBody--> [3] jakarta-Servlet: <https://javadoc.io/static/jakarta.servlet/jakarta.servlet-api/5.0.0/jakarta/servlet/Servlet.html> [4] Wikipedia "Jakarta Servlet": <https://en.wikipedia.org/wiki/Jakarta_Servlet> --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
