public void setCacheManager(CacheManager cacheManager) {
        this.cacheManager = cacheManager;
        afterCacheManagerSet();
    }
Sets the <tt>CacheManager</tt> to be used for data caching to reduce EIS round trips.
<p/>
This property is <tt>null</tt> by default, indicating that caching is turned off.

@param cacheManager the <tt>CacheManager</tt> to use for data caching, or <tt>null</tt> to disable caching.
core/src/main/java/org/apache/shiro/realm/CachingRealm.java