How often the listeners as well as filters are used in applications by companies??

[Jyoti Vaskar]

I know the theory of listeners & filters.
But have not used yet in my applications anywhen.

How often the listeners as well as filters are used in applications by companies??

Can you guys please share your experience with filters/listeners you used & for what purpose?

thank you.

[pete stein]

Jyoti Vaskar wrote:I know the theory of listeners & filters.
But have not used yet in my applications anywhen.

Have you ever created a GUI application such as a Swing or AWT app?

[Jyoti Vaskar]

pete stein wrote:

Jyoti Vaskar wrote:I know the theory of listeners & filters.
But have not used yet in my applications anywhen.

Have you ever created a GUI application such as a Swing or AWT app?

Not actually.
But my question was related to Listeners used with servlets.

[pete stein]

Jyoti Vaskar wrote:But I'm asking here for Listeners used with servlets.

I didn't see that mentioned anywhere in the original post.

[David Newton]

I don't think I've written a web app that hasn't used both, or their equivalent, ever. Sometimes frameworks introduce their own filters and listeners as well (like Spring's startup listener, or Hibernate's open-session-in-view filter). They're ubiquitous.

[Jyoti Vaskar]

David Newton wrote:I don't think I've written a web app that hasn't used both, or their equivalent, ever. Sometimes frameworks introduce their own filters and listeners as well (like Spring's startup listener, or Hibernate's open-session-in-view filter). They're ubiquitous.

thanks for sharing David.
I have a 1 yr of exp in java & hardly worked on any of the big projects at my experience.

I'd be thankfull to you if you can tell the purpose behind the use of it in your application as I'm keen to know its uses.

thank you.

[David Newton]

I gave two examples; how many would you like?

[Jyoti Vaskar]

David Newton wrote:(like Spring's startup listener, or Hibernate's open-session-in-view filter)
I gave two examples; how many would you like?

Yesterday I searched for it & got two examples of listeners ie.
1) Creating a database connection before application starts & closing before it stops.
2) Counting the application startups.

& of filter is
modifying the request parameters before sending it to server.
changing the response before sending it to view etc.

And I got some idea.

Actually from your answer I couldnt even understand what is open-session-in-view & hence couldnt even be able to know that these are examples which you have given??
Hence I'd asked for examples again bymistake :confused:.

Anyways thanks for your co-operation David.

[David Newton]

You could search for "open session in view", I suppose.

GZIP filters are also a typical filter usage.