Creating ‘mini-caches’ in Java to speed up database calls.

Java has a cool construct called a Hashmap, this can be used to cache the result of a routine using a key.

For example.

Map cache=new HashMap();
public String getUnitsAtSite(String siteCode) {
     // is the sitecode already in the cache?
     if (cache.containsKey(siteCode)) return (String)cache.get(siteCode);
     String getSites=.... < get data from data base

     cache.put(siteCode,getSites);
     return getSites;

}

Now ofcourse there are downsides, if the data changes we won't see it - ofcourse we could do a cache.clear(); or cache.delete(key) on save of a change of record.
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About Paul C

I am a Senior Java programmer/Web Technologies, Play in a band called Mandolin Monday, I have a cat and I live on a boat.

Posted on July 31, 2012, in glassfish, MYSQL. Bookmark the permalink. Leave a comment.

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