RE: [OT] caching strategy

["Hookom, Jacob" <Ja...@redline.mckhboc.com>]

create primary keys for your data, create an identity object to represent
legacy data, create a hashmap or cache interface and use either LRU's or
Softly referenced caching.  Pretty straight forward.  Logic would be "select
primary keys + lastModified" if changed or not found, create, else pull from
cache.

--------
Jacob Hookom
Senior Programmer/Analyst
McKesson Medical Surgical
Golden Valley, MN


-----Original Message-----
From: Erik Price [mailto:eprice@ptc.com]
Sent: Friday, June 20, 2003 3:41 PM
To: Struts Users Mailing List
Subject: [OT] caching strategy


There is an internal app that is used at my company and I am tossing 
around the idea of investing a little time and energy into making a 
simple web front-end for accessing data in this app.  However, it does 
not use a traditional database with JDBC connections, so I could not 
maintain a connection pool with which to fetch app data.

I am thinking that I could use a session bean to query the app (I have 
already written a codebase in Java to fetch the app's data from 
queries), but things like list boxes would need to be populated in 
JSP/HTML forms from semi-current data.  This is the sort of thing that I 
would prefer to cache rather than constantly be querying the application 
whenever someone requests a new HTML/JSP.

In short, when building a J2EE app to access legacy applications, what 
is a good strategy for maintaining an app-level cache?

Thanks for your opinions.


Erik


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Re: [OT] caching strategy

[Erik Price <ep...@ptc.com>]

Hookom, Jacob wrote:
> create primary keys for your data, create an identity object to represent
> legacy data, create a hashmap or cache interface and use either LRU's or
> Softly referenced caching.  Pretty straight forward.  Logic would be "select
> primary keys + lastModified" if changed or not found, create, else pull from
> cache.

Okay I understand the first part -- proxy the legacy data entities with 
Java objects, and use a HashMap-based cache (perhaps using the primary 
keys as the hash's keys).  But...

What are LRU's?  Softly referenced caching -- have a particularly good 
resource on this topic?


Erik


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