Need help in Implementing cache using hashmap

[Sam Baheerathan]

Hi,

I m developing employee management system using java and enterpriseDb. in this system i m planning to manage the employee details in a hash-map to reduce the disk I/O s. since this system will be used in several machines, i need to find a way to update the hash-map when ever a employee record is updated in the database. so that all the machines can have the latest updated records.
can anyone suggest me a way to implement this?

[William Brogden]

A google search for "java cache open source" found an enormous number of hits.

People have been fiddling with caching since Java 1.0

Bill

[Deepak Bala]

I would take Bill up on his suggestion. Developing a good cache is not trivial. How do you invalidate a cache ? When does a cache become stale ? When do you refresh the cache ? How do you deal with concurrency ? etc etc

There are many caching solutions that can sit between the caller and the DB. They should help.

[Sandeep Murthy]

You can give "Hibernate" a try for starters.

[Winston Gutkowski]

Sam Baheerathan wrote:I m developing employee management system using java and enterpriseDb. in this system i m planning to manage the employee details in a hash-map to reduce the disk I/O s. since this system will be used in several machines, i need to find a way to update the hash-map when ever a employee record is updated in the database. so that all the machines can have the latest updated records.
can anyone suggest me a way to implement this?

Well, LinkedHashMap has some goodies that allow you to implement LRU (least-recently-used) caches quite easily. Specifically, have a look at the removeEldestEntry() method.

However, you haven't really given us enough information to give you informed advice.

Winston