How to pick every new file in the local directory by a custom tcode

Hi ,

I have a requirement,

A file say ( customer.txt  containing customer number only 1 record in it)  will be placed in the local drive by the 3rd party tool, when ever there is a new file, a custom transaction has to trigger say zcustomer_details, this zcustomer_details will pick the file retrieve the customer number and display the customer details in the transaction.

question is who to check for every new file placed by 3rd party tool and refresh the transaction.

Thanks,

Laxmi.Suryadevara