XACML Decision Caching Design Considerations
Cache Flush Strategy: With the enhancedSpeed option, we rely on a LRU cache based on LinkedHashMap. This basically means that the cache is going to be long lived. Unless the PDP is restarted, the cache will not flush. With the correctness approach (enhancedSpeed option set to false), the interal cache is a WeakHashMap implementation, which basically means that the cache is flushed quite often - resulting in dynamic rules (xacml policies) changing at run time yielding correct results all the time.