about listener

[Sundar Murthi]

Hi ranchers
i attended this qn in mock exam i am confused with the answer

How do you declare listeners MyFirstListener and MySecondListener in web.xml file. (select one)

 
A    <listener>
 
<listener-class>MyFirstListener</listener>
 
<istener-class>MySecondListener</listener> 
 
</listener>
 
B    <listener>
 
           <listener-class>MyFirstListener</listener-class>
 
</listener>
 
<listener>
 
           <listener-class>MySecondListener</listener-class>
 
</listener>
 
C    
<listeners>
 
       MyFirstListener
 
       MySecondListener 
 
</listeners>
 
D    
<listener>
 
           MyFirstListener
 
 </listener>
 
<listener>
 
           MySecondListener
 
</listener>
 
 

i thought the answer is A but the ansewr given is B . which one is correct.

[liny]

The answer is B exactly!
Because you can not write multi <listener-class> in a <listener> tag.
You have to separate them into two <listener> tag!
One <listener> tag have ONLY ONE <listener-class> tag.

[Sundar Murthi]

But we can also set two or more listener in a single listener tag?

the two are valid can u able to conform to me


thanks

[liny]

Originally posted by Sundar Murthi:
But we can also set two or more listener in a single listener tag?

the two are valid can u able to conform to me


thanks

Set two or more listener-class in a listener tag is useless.
Here is the web-app_2_3.dtd you can read.
You can find the "listener-class" in the web-app 2.3.
And it says "<!ELEMENT listener (listener-class)>".
That means one listener MUST and ONLY have ONE listener-class tag.
In my opinion, if you set more listener-class, Container will ignore second and others!

PS: in web-app_2_3.dtd
* means you can add this tag zero to many.
? means you can add this tag zero to one at most.
+ means you must add this tag one or more.
if there is no punctuation, it means you must add only one this tag.

If I am wrong, please tell me.
[ December 10, 2004: Message edited by: liny liny ]

[Bianca Hagen]

you are right