DO NOT REPLY [Bug 26322] New: - WebLogic hot-deploy breaks Tiles; TilesRequestProcessor is not serializable

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http://nagoya.apache.org/bugzilla/show_bug.cgi?id=26322

WebLogic hot-deploy breaks Tiles; TilesRequestProcessor is not serializable

           Summary: WebLogic hot-deploy breaks Tiles; TilesRequestProcessor
                    is not serializable
           Product: Struts
           Version: 1.1 Final
          Platform: All
        OS/Version: Other
            Status: NEW
          Severity: Normal
          Priority: Other
         Component: Tiles framework
        AssignedTo: struts-dev@jakarta.apache.org
        ReportedBy: renaud+apache@waldura.com


Please refer to the following documents for background information about this 
issue:

http://www.mail-archive.com/struts-user@jakarta.apache.org/msg53294.html
http://marc.theaimsgroup.com/?l=struts-user&m=105203952331713
http://marc.theaimsgroup.com/?l=struts-user&m=105188532730261
http://marc.theaimsgroup.com/?l=struts-user&m=105268268519113

To summarize: WebLogic (at least v6 and v7) attempts to serialize the 
TilesRequestProcessor when re-deploying the Webapp in development mode. The 
TilesRequestProcessor is not serializable, and loses the Tiles definitions. 
This results in NullPointerException and/or NotSerializableException when using 
the app after automatic redeploy.

This bug report proposes a workaround for this problem, in the hope it will 
help others and maybe motivate an actual fix.

The attached class extends the Struts Action servlet and fixes the problem by 
reloading the Tiles definitions when they have disappeared.

/**
 * In development mode, WebLogic 7.0 automatically redeploys servlets by 
creating a new classloader, 
 * then propagates the servlet context to the new servlet classes by 
serializing it. 
 * For some reason unknown to 
 * me, this serialization operation drops the Tiles definitions. The re-
deployed servlets fail
 * with a NPE when looking up any Tiles definition. This basically breaks 
automatic redeployment.
 * <p> 
 * This class works around this issue by detecting when the request processor 
(which holds the
 * Tiles definitions) was serialized, and re-creating a new instance when that 
is the case.
 * The Tiles defs are then reloaded as well. This should only happen when the 
servlet context 
 * was serialized, ie. servlets were redeployed. 
 * 
 * @author Renaud Waldura
 */


--- web.xml ---

<servlet>
<servlet-name>action</servlet-name>
<servlet-class>com.aravo.framework.ui.struts.action.WebLogicRedeployableActi
onServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<init-param>
<param-name>debug</param-name>
<param-value>0</param-value>
</init-param>
<init-param>
<param-name>detail</param-name>
<param-value>0</param-value>
</init-param>
<load-on-startup>2</load-on-startup>
</servlet>

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