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.
From Red Hat JBoss Data Grid 6.3 onwards, the map methods size(), values(), keySet(), and entrySet() include entries in the cache loader by default whereas previously these methods only included the local data container. The underlying cache loader directly affects the performance of these commands. As an example, when using a database, these methods run a complete scan of the table where data is stored which can result in slower processing. Use Cache.getAdvancedCache().withFlags(Flag.SKIP_CACHE_LOAD).values() to maintain the old behavior and not loading from the cache loader which would avoid the slower performance.
In JBoss Data Grid 6.3 the Cache#size() method returned only the number of entries on the local node, ignoring other nodes for clustered caches and including any expired entries. While the default behavior was not changed in JBoss Data Grid 6.4 or later, accurate results can be enabled for bulk operations, including size(), by setting the infinispan.accurate.bulk.ops system property to true. In this mode of operation, the result returned by the 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.
In JBoss Data Grid 6.3, the Hot Rod size() method obtained the size of a cache by invoking the STATS operation and using the returned numberOfEntries statistic. This statistic is not an accurate measurement of the number of entries in a cache because it does not take into account expired and passivated entries and it is only local to the node that responded to the operation. As an additional result, when security was enabled, the client would need the ADMIN permission instead of the more appropriate BULK_READ.
SIZE operation, and the clients have been updated to use this operation for the size() method. The JBoss Data Grid server will need to be started with the infinispan.accurate.bulk.ops system property set to true so that size can be computed accurately.
1.3.4. Custom Interceptors
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 Declaratively
Procedure 1.2. Adding Custom Interceptors
<namedCache name="cacheWithCustomInterceptors">
<customInterceptors>
<interceptor position="FIRST" class="com.mycompany.CustomInterceptor1">
<properties>
<property name="attributeOne" value="value1" />
<property name="attributeTwo" value="value2" />
</properties>
</interceptor>
<interceptor position="LAST" class="com.mycompany.CustomInterceptor2"/>
<interceptor index="3" class="com.mycompany.CustomInterceptor1"/>
<interceptor before="org.infinispan.interceptors.CallInterceptor" class="com.mycompany.CustomInterceptor2"/>
<interceptor after="org.infinispan.interceptors.CallInterceptor" class="com.mycompany.CustomInterceptor1"/>
</customInterceptors>
</namedCache>
Define Custom Interceptors
All custom interceptors must extend org.infinispan.interceptors.base.BaseCustomInterceptor.Define the Position of the New Custom Interceptor
Interceptors must have a defined position. These options are mutually exclusive, meaning an interceptor cannot have both a position attribute and index attribute. Valid options are:via Position Attribute
FIRST- Specifies that the new interceptor is placed first in the chain.LAST- Specifies that the new interceptor is placed last in the chain.OTHER_THAN_FIRST_OR_LAST- Specifies that the new interceptor can be placed anywhere except first or last in the chain.
via Index Attribute
- The
indexidentifies the position of this interceptor in the chain, with 0 being the first position. - The
aftermethod places the new interceptor directly after the instance of the named interceptor specified via its fully qualified class name. - The
beforemethod places the new interceptor directly before the instance of the named interceptor specified via its fully qualified class name.
Define Interceptor Properties
Define specific interceptor properties.
Apply Other Custom Interceptors
In this example, the next custom interceptor is called CustomInterceptor2.
Note
OTHER_THAN_FIRST_OR_LAST may cause the CacheManager to fail.
Note
1.3.4.3. 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);
