Temporary URLs in a Tomcat REST Server

I have a REST Server running on Tomcat 5.5. Some of the services need to return a temporary URL to contain a generated PDF document. How can I do thi开发者_如何学Pythons in Tomcat? How can I expire the document after a reasonable amount of time.

I could just create the document in memory and store it in some kind of HashMap, but I will lose the document if I have to restart Tomcat, and generating too many documents will cause an out-of-memory error.

I am using RESTEasy 1.2.1 GA as my REST framework.

Thanks.

put it in memcached which support timeout.