1.3. The AdvancedCache Interface
AdvancedCache interface, geared towards extending JBoss Data Grid, in addition to its simple Cache Interface. The AdvancedCache Interface can:
- Inject custom interceptors
- Access certain internal components
- Apply flags to alter the behavior of certain cache methods
AdvancedCache:
AdvancedCache advancedCache = cache.getAdvancedCache();
1.3.1. Flag Usage with the AdvancedCache Interface
AdvancedCache.withFlags() to apply any number of flags to a cache invocation.
Example 1.3. Applying Flags to a Cache Invocation
advancedCache.withFlags(Flag.CACHE_MODE_LOCAL, Flag.SKIP_LOCKING)
.withFlags(Flag.FORCE_SYNCHRONOUS)
.put("hello", "world");1.3.2. Custom Interceptors and the AdvancedCache Interface
AdvancedCache Interface provides a mechanism that allows advanced developers to attach custom interceptors. Custom interceptors can alter the behavior of the Cache API methods and the AdvacedCache Interface can be used to attach such interceptors programmatically at run time.
1.3.3. Limitations of Map Methods
size(), values(), keySet() and entrySet(), can be used with certain limitations with Red Hat JBoss Data Grid as they are unreliable. These methods do not acquire locks (global or local) and concurrent modification, additions and removals are excluded from consideration in these calls.
In JBoss Data Grid 7.0 the map methods size(), values(), keySet(), and entrySet() include entries in the cache loader by default. The cache loader in use will determine the performance of these commands; for instance, when using a database these methods will run a complete scan of the table where data is stored, which may result in slower processing. To not load entries from the cache loader, and avoid any potential performance hit, use Cache.getAdvancedCache().withFlags(Flag.SKIP_CACHE_LOAD) before executing the desired method.
In JBoss Data Grid 7.0 the Cache.size() method provides a count of all elements in both this cache and cache loader across the entire cluster. When using a loader or remote entries, only a subset of entries is held in memory at any given time to prevent possible memory issues, and the loading of all entries may be slow.
size() method is affected by the flags org.infinispan.context.Flag#CACHE_MODE_LOCAL, to force it to return the number of entries present on the local node, and org.infinispan.context.Flag#SKIP_CACHE_LOAD, to ignore any passivated entries. Either of these flags may be used to increase performance of this method, at the cost of not returning a count of all elements across the entire cluster.
In JBoss Data Grid 7.0 the Hot Rod protocol contain a dedicated SIZE operation, and the clients use this operation to calculate the size of all entries.
1.3.4. Custom Interceptors
Warning
1.3.4.1. Custom Interceptor Design
- A custom interceptor must extend the
CommandInterceptor. - A custom interceptor must declare a public, empty constructor to allow for instantiation.
- A custom interceptor must have JavaBean style setters defined for any property that is defined through the
propertyelement.
1.3.4.2. Adding Custom Interceptors Programmatically
AdvancedCache.
Example 1.4. Obtain a Reference to the AdvancedCache
CacheManager cm = getCacheManager();
Cache aCache = cm.getCache("aName");
AdvancedCache advCache = aCache.getAdvancedCache();addInterceptor() method to add the interceptor.
Example 1.5. Add the Interceptor
advCache.addInterceptor(new MyInterceptor(), 0);
