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About init(ServletConfig)/Intialization

Gagan Indus
Ranch Hand

Joined: Feb 28, 2001
Posts: 346
GenericServlet has one of init method as :
void init(ServletConfig config)
and also GenericServlet implements da ServletConfig interface.
Spec says " The container initializes the servlet instance by calling the init method of the Servlet interface with a
unique (per servlet declaration) object implementing the ServletConfig interface."

My questions are :
- "What is the need/use of GenericServlet implementing ServletConfig itself , as it is the responsibility of web-container to pass config-Object to init()."
( GenericServlet IS-A ServletConfig sounds weird to my ears )
- As GenericServlet implements ServletConfig , any subclass of it 'll inherit methods in interface ServletConfig too. So , suppose i subclass GenericServlet , and in some method of this subclass i call some method of ServletConfig , say i call getSevletContext() . In this case " Do GenericServlet class have some of its own implementation of getServletContext() , or does it internally calls the same method upon ServletConfig passed in init() ? "
( as reference to original ServletConfig passed in init() is stored )

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Gagan (/^_^\) SCJP2
Die-hard JavaMonk -- little Java a day , keeps u going .


Gagan (/^_^\) SCJP2 SCWCD IBM486 <br />Die-hard JavaMonk -- little Java a day, keeps you going.<br /><a href="http://www.objectfirst.com/blog" target="_blank" rel="nofollow">My Blog</a>
Stephane Nicoll
Greenhorn

Joined: Oct 19, 2001
Posts: 4
In short, all is in the name : Generic ... The purpose is to set a simple class which allow to develop rapidly generic servlet. That's all !
Anyway, most developpers use Http version of the servlet.
Tim Duncan
Ranch Hand

Joined: Aug 20, 2001
Posts: 150
Originally posted by Gagan Indus:
So , suppose i subclass GenericServlet , and in some method of this subclass i call some method of ServletConfig , say i call getSevletContext() . In this case " Do GenericServlet class have some of its own implementation of getServletContext() , or does it internally calls the same method upon ServletConfig passed in init() ? "
( as reference to original ServletConfig passed in init() is stored )

GenericServlet just passes on the call to the ServletConfig object that it stored.
If you get the "jakarta-servletapi-4" package that is available for download with Tomcat, you can check out the implementation of GenericServlet for yourself in the src directory.
Here's the URL for the package:
http://jakarta.apache.org/builds/jakarta-tomcat-4.0/release/v4.0/jakarta-servletap i-4.tar.gz
(there's .zip version too)


[This message has been edited by Tim Duncan (edited October 19, 2001).]
Gagan Indus
Ranch Hand

Joined: Feb 28, 2001
Posts: 346
Thankx Stephane and Tim !
Stephane , so was it to make servlet developers life lill 'easy' ?
I knw we all extend HttpServlet , but it IS-A GenericServlet , which further IS-A Servlet-Config , which effectively implies HttpServlet IS-A Servlet-Config . So sometimes to make life easier , we have to relax OOPs-thinga lill
Yes Tim i got da perfect ans to second q , by looking at source code . thankx
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Gagan (/^_^\) SCJP2
Die-hard JavaMonk -- little Java a day , keeps u going .
 
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