using filters with struts

[senthil kumar m]

it is a struts project..

the filter configuration is as follows,

<filter> 
<filter-name>samplefilter</filter-name> 
<filter-class>org.samplepack.SampleFilterXXX</filter-class> 
</filter>
 <filter-mapping> 
<filter-name>samplefilter</filter-name> 
<servlet-name>action</servlet-name>
 </filter-mapping> 

and the servlet mapping is as follows,

<servlet-mapping> 
<servlet-name>action</servlet-name>
 <url-pattern>*.do</url-pattern> 
</servlet-mapping> 

Here this filter will be executed for all action classes..right?? [have a slight doubt on that too ]

I planned to use it for checking the session informations..

is it a good practice?

can you post the situations whereever i can apply this effectively ?