I wanted to create my own eviction policy where the time to live would be 
determined by an attribute of the object.  I am currently using the FIFOPolicy. 
 It looks like I could extend that and override the getEvictionAlgorithm method 
to return a custom Policy inheriting from the LRUAlgorithm.  Then I could 
override the evict method and decide if I really wanted to evict the node or 
not.  

One of the problems I'm seeing though has to do with the prune method.  I 
wouldn't want to overide the eviction of nodes when the eviction is occuring 
because of the number of items (I don't want to run out of memory).  But I 
would want to override the pruning items based on age.

The way I was looking to do this seems like a hack.  Is there a better way to 
do this?

To give some perspective:

I have items in a cache representing the price of an item.  The prices of these 
items may change at any time.  The source of the price comes from an SAP 
backend.  One of the attributes on the priced item is a field indicating the 
relevancy of the item saying how well the item has sold in the last few months. 
 Items which are sold more frequently should expire in the cache faster than 
items that don't sell as frequently.  

Before, I started looking at implementing a custom eviction policy, I was 
wrapping access to the data in a DAO pattern, after pulling the item out of the 
cache I was examing the field and checking the retieval time of the item 
manually.  If it was too old, I would get the item directly from the SAP 
backend.

Thanks.



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