jfun.yan.web
Class YanLoaderServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          jfun.yan.web.YanLoaderServlet

All Implemented Interfaces:

java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

public class YanLoaderServlet
extends javax.servlet.http.HttpServlet

Major portion of this class is copied from the Spring framework.

Bootstrap servlet to start up Yan's root container. Simply delegates to YanLoader.

This servlet should have a lower load-on-startup value in web.xml than any servlets that access the root web application context.

Note that this class has been deprecated for containers implementing Servlet API 2.4 or higher, in favor of YanLoaderListener.
According to Servlet 2.4, listeners must be initialized before load-on-startup servlets. Many Servlet 2.3 containers already enforce this behavior. If you use such a container, this servlet can be replaced with YanLoaderListener. Else or if working with a Servlet 2.2 container, stick with this servlet.

Servlet 2.3 containers known to work with bootstrap listeners are:

• Apache Tomcat 4.x+
• Jetty 4.x+
• Resin 2.1.8+
• Orion 2.0.2+
• BEA WebLogic 8.1 SP3

For working with any of them, YanLoaderListener is recommended.

Servlet 2.3 containers known not to work with bootstrap listeners are:

• BEA WebLogic up to 8.1 SP2
• IBM WebSphere 5.x
• Oracle OC4J 9.0.3

If you happen to work with such a server, this servlet has to be used.

So unfortunately, the only context initialization option that is compatible with all Servlet 2.3 containers is this servlet.

Note that a startup failure of this servlet will not stop the rest of the web application from starting, in contrast to a listener failure. This can lead to peculiar side effects if other servlets get started that depend on initialization of the root web application context.

Author:

Ben Yu.

See Also:

YanLoader, YanLoaderListener, Serialized Form

Constructor Summary

YanLoaderServlet()

Method Summary

protected YanLoader	createYanLoader() Create the YanLoader to use.
void	destroy() Close the root web application context.
java.lang.String	getServletInfo()
YanLoader	getYanLoader() Return the YanLoader used by this servlet.
void	init() Initialize the root web application context.
void	service(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) This should never even be called since no mapping to this servlet should ever be created in web.xml.

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service

Methods inherited from class javax.servlet.GenericServlet

getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletName, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

YanLoaderServlet

public YanLoaderServlet()

Method Detail

init

public void init()
          throws javax.servlet.ServletException

Initialize the root web application context.

Overrides:

init in class javax.servlet.GenericServlet

Throws:

javax.servlet.ServletException

createYanLoader

protected YanLoader createYanLoader()

Create the YanLoader to use. Can be overridden in subclasses.

Returns:

the new YanLoader

getYanLoader

public YanLoader getYanLoader()

Return the YanLoader used by this servlet.

destroy

public void destroy()

Close the root web application context.

Specified by:

destroy in interface javax.servlet.Servlet

Overrides:

destroy in class javax.servlet.GenericServlet

service

public void service(javax.servlet.http.HttpServletRequest request,
                    javax.servlet.http.HttpServletResponse response)
             throws java.io.IOException

This should never even be called since no mapping to this servlet should ever be created in web.xml. That's why a correctly invoked Servlet 2.3 listener is much more appropriate for initialization work ;-)

Overrides:

service in class javax.servlet.http.HttpServlet

Throws:

java.io.IOException

getServletInfo

public java.lang.String getServletInfo()

Specified by:

getServletInfo in interface javax.servlet.Servlet

Overrides:

getServletInfo in class javax.servlet.GenericServlet