如何在应用程序级别缓存复杂的Java对象

Question

I am looking for a solution to cache complex objects in java at application level.

For example, i want to load some data set from database to memory and make my application services to work on top of the objects loaded into memory. I considered this in order to improve performance.

But I am wondering how to keep the relationships of an object in a cache.

That is for example,

If a category has many items, what is the best approach to store the relationship. My idea is to store category and items separately and store the relationship in some other place. This is because I use hibernate and the associations are configured to lazy loading.

Please share your thoughts to approach this problem.

Answer 1

Are you sure you need custom cache implementation on application level?

Hibernate have first and second level cache, doesn't it enough for you? Think about how much memory you will use to store all your hibernate objects in your own, hand-written cache. If it also will read-write, complicity of that decision can bring you more problems than benefits. And it will be wheel reinvention, of course.

Read about how second level cache work in hibernate. http://www.javalobby.org/java/forums/t48846.html and other perfomance tuning: http://docs.jboss.org/hibernate/orm/3.3/reference/en/html/performance.html

Iteration over lazy loaded collecitons depends of which pattern you're using to work with sesions. Good example: https://community.jboss.org/wiki/OpenSessionInView

Answer 2

Firstly if you are aiming for complex objects, dont cache them in memory. It will significantly degrade performance as number of objects increase. Go for a concept of object repositories. You can store objects in any complex form and it will suit your requirements

Checkout following ir techs. noDB

Or JORM

Take a look at ehcache , as suggested in comments if you are looking for a cache lib Here ehcache