24.2. Using the Infinispan CDI Module

The Infinispan CDI module can be used for the following purposes:
  • To configure and inject Infinispan caches into CDI Beans and Java EE components.
  • To configure cache managers.
  • To control storage and retrieval using CDI annotations.

24.2.1. Configure and Inject Infinispan Caches

24.2.1.1. Inject an Infinispan Cache

An Infinispan cache is one of the multiple components that can be injected into the project's CDI beans.
The following code snippet illustrates how to inject a cache instance into the CDI bean:
public class MyCDIBean {
    @Inject
    Cache<String, String> cache;
}

24.2.1.2. Inject a Remote Infinispan Cache

The code snippet to inject a normal cache is slightly modified to inject a remote Infinispan cache, as follows:
public class MyCDIBean {
    @Inject
    RemoteCache<String, String> remoteCache;
}

24.2.1.3. Set the Injection's Target Cache

The following are the three steps to set an injection's target cache:
  1. Create a qualifier annotation.
  2. Add a producer class.
  3. Inject the desired class.
24.2.1.3.1. Create a Qualifier Annotation
To use CDI to return a specific cache, create custom cache qualifier annotations as follows:

Example 24.1. Custom Cache Qualifier

@javax.inject.Qualifier
@Target({ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface SmallCache {}
Use the created @SmallCache qualifier to specify how to create specific caches.
24.2.1.3.2. Add a Producer Class
The following code snippet illustrates how the @SmallCache qualifier (created in the previous step) specifies a way to create a cache:

Example 24.2. Using the @SmallCache Qualifier

import org.infinispan.configuration.cache.Configuration;
import org.infinispan.configuration.cache.ConfigurationBuilder;
import org.infinispan.cdi.ConfigureCache;
import javax.enterprise.inject.Produces;

public class CacheCreator {
    @ConfigureCache("smallcache")
    @SmallCache
    @Produces
    public Configuration specialCacheCfg() {
        return new ConfigurationBuilder()
                   .eviction()
                       .strategy(EvictionStrategy.LRU)
                       .maxEntries(10)
                   .build();
    }
}
The elements in the code snippet are:
  • @ConfigureCache specifies the name of the cache.
  • @SmallCache is the cache qualifier.
24.2.1.3.3. Inject the Desired Class
Use the @SmallCache qualifier and the new producer class to inject a specific cache into the CDI bean as follows:
public class MyCDIBean {
    @Inject @SmallCache
    Cache<String, String> mySmallCache;
}

24.2.2. Configure Cache Managers with CDI

A Red Hat JBoss Data Grid Cache Manager (both embedded and remote) can be configured using CDI. Whether configuring an embedded or remote cache manager, the first step is to specify a default configuration that is annotated to act as a producer.

24.2.2.1. Specify the Default Configuration

Specify a method annotated as a producer for the Red Hat JBoss Data Grid configuration object to replace the default Infinispan Configuration. The following sample configuration illustrates this step:

Example 24.3. Specifying the Default Configuration

public class Config {
    @Produces
    public Configuration defaultEmbeddedConfiguration () {
        return new ConfigurationBuilder()
                         .eviction()
                                 .strategy(EvictionStrategy.LRU)
                                 .maxEntries(100)
                         .build();
    }
}

Note

CDI adds a @Default qualifier if no other qualifiers are provided.
If a @Produces annotation is placed in a method that returns a Configuration instance, the method is invoked when a Configuration object is required.
In the provided example configuration, the method creates a new Configuration object which is subsequently configured and returned.

24.2.2.2. Override the Creation of the Embedded Cache Manager

Creating Non Clustered Caches

After a producer method is annotated, this method will be called when creating an EmbeddedCacheManager, as follows:

Example 24.4. Create a Non Clustered Cache

public class Config {
    
    @Produces
    @ApplicationScoped
    public EmbeddedCacheManager defaultEmbeddedCacheManager() {
        Configuration cfg = new ConfigurationBuilder()
                                    .eviction()
                                            .strategy(EvictionStrategy.LRU)
                                            .maxEntries(150)
                                    .build();
        return new DefaultCacheManager(cfg);
    }
}
The @ApplicationScoped annotation specifies that the method is only called once.
Creating Clustered Caches

The following configuration can be used to create an EmbeddedCacheManager that can create clustered caches.

Example 24.5. Create Clustered Caches

public class Config {

	@Produces
	@ApplicationScoped
	public EmbeddedCacheManager defaultClusteredCacheManager() {
		GlobalConfiguration g = new GlobalConfigurationBuilder()
				.clusteredDefault()
				.transport()
				.clusterName("InfinispanCluster")
				.build();
		Configuration cfg = new ConfigurationBuilder()
				.eviction()
				.strategy(EvictionStrategy.LRU)
				.maxEntries(150)
				.build();
		return new DefaultCacheManager(g, cfg);
	}
}
Invoke the Method to Generate an EmbeddedCacheManager

The method annotated with @Produces in the non clustered method generates Configuration objects. The methods in the clustered cache example annonated with @Produces generate EmbeddedCacheManager objects.

Add an injection as follows in your CDI Bean to invoke the appropriate annotated method. This generates EmbeddedCacheManager and injects it into the code at runtime.

Example 24.6. Generate an EmbeddedCacheManager

...
@Inject
EmbeddedCacheManager cacheManager;
...

24.2.2.3. Configure a Remote Cache Manager

The RemoteCacheManager is configured in a manner similar to EmbeddedCacheManagers, as follows:

Example 24.7. Configuring the Remote Cache Manager

public class Config {
	@Produces
	@ApplicationScoped
	public RemoteCacheManager defaultRemoteCacheManager() {
           Configuration conf = new ConfigurationBuilder().addServer().host(ADDRESS).port(PORT).build();
            return new RemoteCacheManager(conf);
	}
}}

24.2.2.4. Configure Multiple Cache Managers with a Single Class

A single class can be used to configure multiple cache managers and remote cache managers based on the created qualifiers. An example of this is as follows:

Example 24.8. Configure Multiple Cache Managers

public class Config {
    @Produces
    @ApplicationScoped
    public org.infinispan.manager.EmbeddedCacheManager
    defaultEmbeddedCacheManager() {
        Configuration cfg = new ConfigurationBuilder()
                .eviction()
                .strategy(EvictionStrategy.LRU)
                .maxEntries(150)
                .build();
        return new DefaultCacheManager(cfg);
    }

    @Produces
    @ApplicationScoped
    @DefaultClustered
    public org.infinispan.manager.EmbeddedCacheManager
    defaultClusteredCacheManager() {
        GlobalConfiguration g = new GlobalConfigurationBuilder()
                .clusteredDefault()
                .transport()
                .clusterName("InfinispanCluster")
                .build();
        Configuration cfg = new ConfigurationBuilder()
                .eviction()
                .strategy(EvictionStrategy.LRU)
                .maxEntries(150)
                .build();
        return new DefaultCacheManager(g, cfg);
    }

    @Produces
    @ApplicationScoped
    @DefaultRemote
    public RemoteCacheManager
    defaultRemoteCacheManager() {
        org.infinispan.client.hotrod.configuration.Configuration conf = new org.infinispan.client.hotrod.configuration.ConfigurationBuilder().addServer().host(ADDRESS).port(PORT).build();
        return new RemoteCacheManager(conf);
    }

    @Produces
    @ApplicationScoped
    @RemoteCacheInDifferentDataCentre
    public RemoteCacheManager newRemoteCacheManager() {
        org.infinispan.client.hotrod.configuration.Configuration confid = new org.infinispan.client.hotrod.configuration.ConfigurationBuilder().addServer().host(ADDRESS_FAR_AWAY).port(PORT).build();
        return new RemoteCacheManager(confid);
    }
}

24.2.3. Storage and Retrieval Using CDI Annotations

24.2.3.1. Configure Cache Annotations

Specific CDI annotations are accepted for the JCache (JSR-107) specification. All included annotations are located in the javax.cache package.
The annotations intercept method calls on CDI beans and perform storage and retrieval tasks as a result of these interceptions.

Important

CDI is supported in both Remote Client-Server Mode and Library Mode; however, annotations such as @CachePut, @CacheRemove, @CacheRemoveAll, and @CacheResult cannot be used in Remote Client-Server Mode.

24.2.3.2. Enable Cache Annotations

JBoss Data Grid includes two sets of interceptors depending on how they are used. Interceptors can be added to the CDI bean archive using the beans.xml file.
Option 1: CDI Interceptors

Adding the following code adds interceptors such as the InjectedCacheResultInterceptor, InjectedCachePutInterceptor, InjectedCacheRemoveEntryInterceptor and the InjectedCacheRemoveAllInterceptor:

Example 24.9. Adding CDI Interceptors

<beans xmlns="http://java.sun.som/xml/ns/javaee"
       xmlns:xsi="http://www/w3/org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/beans_1_0.xsd" >
	<interceptors>
		<class>org.infinispan.jcache.annotation.InjectedCacheResultInterceptor</class>
		<class>org.infinispan.jcache.annotation.InjectedCachePutInterceptor</class>
		<class>org.infinispan.jcache.annotation.InjectedCacheRemoveEntryInterceptor</class>
		<class>org.infinispan.jcache.annotation.InjectedCacheRemoveAllInterceptor</class>
	</interceptors>
</beans>
Option 2: JCache Interceptors

Adding the following code adds interceptors such as the CacheResultInterceptor, CachePutInterceptor, CacheRemoveEntryInterceptor and the CacheRemoveAllInterceptor:

Example 24.10. Adding JCache Interceptors

<beans xmlns="http://java.sun.com/xml/ns/javaee"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">

   <interceptors>
      <class>org.infinispan.jcache.annotation.CacheResultInterceptor</class>
      <class>org.infinispan.jcache.annotation.CachePutInterceptor</class>
      <class>org.infinispan.jcache.annotation.CacheRemoveEntryInterceptor</class>
      <class>org.infinispan.jcache.annotation.CacheRemoveAllInterceptor</class>
   </interceptors>

</beans>

Note

The listed interceptors must appear in the beans.xml file for Red Hat JBoss Data Grid to use javax.cache annotations.

24.2.3.3. Caching the Result of a Method Invocation

A common practice for time or resource intensive operations is to save the results in a cache for future access. The following code is an example of such an operation:
public String toCelsiusFormatted(float fahrenheit) {
	return
		NumberFormat.getInstance()
		.format((fahrenheit * 5 / 9) - 32)
		+ " degrees Celsius";
}
A common approach is to cache the results of this method call and to check the cache when the result is next required. The following is an example of a code snippet that looks up the result of such an operation in a cache. If the results are not found, the code snippet runs the toCelsiusFormatted method again and stores the result in the cache.
float f = getTemperatureInFahrenheit();
Cache<Float, String>
	fahrenheitToCelsiusCache = getCache();
String celsius =
	fahrenheitToCelsiusCache = get(f);
     if (celsius == null) {
	     celsius = toCelsiusFormatted(f);
	     fahrenheitToCelsiusCache.put(f, celsius);
     }
In such cases, the Infinispan CDI module can be used to eliminate all the extra code in the related examples. Annotate the method with the @CacheResult annotation instead, as follows:
@javax.cache.annotation.CacheResult
public String toCelsiusFormatted(float fahrenheit) {
	return NumberFormat.getInstance()
	.format((fahrenheit * 5 / 9) - 32)
	+ " degrees Celsius";
}
Due to the annotation, Infinispan checks the cache and if the results are not found, it invokes the toCelsiusFormatted() method call.

Note

The Infinispan CDI module allows checking the cache for saved results, but this approach should be carefully considered before application. If the results of the call should always be fresh data, or if the cache reading requires a remote network lookup or deserialization from a cache loader, checking the cache before call method invocation can be counter productive.
24.2.3.3.1. Specify the Cache Used
Add the following optional attribute (cacheName) to the @CacheResult annotation to specify the cache to check for results of the method call:
@CacheResult(cacheName = "mySpecialCache")
public String doSomething(String parameter) {
<!-- Additional configuration information here -->
}
24.2.3.3.2. Cache Keys for Cached Results
As a default, the @CacheResult annotation creates a key for the results fetched from a cache. The key consists of a combination of all parameters in the relevant method.
Create a custom key using the @CacheKey annotation as follows:

Example 24.11. Create a Custom Key

@CacheResult
public String doSomething
	(@CacheKey String p1,
	@CacheKey String p2,
	String dontCare) {
<!-- Additional configuration information here -->
}
In the specified example, only the values of p1 and p2 are used to create the cache key. The value of dontCare is not used when determining the cache key.
24.2.3.3.3. Generate a Custom Key
Generate a custom key as follows:
import javax.cache.annotation.CacheKey;
import javax.cache.annotation.CacheKeyGenerator;
import javax.cache.annotation.CacheKeyInvocationContext;
import java.lang.annotation.Annotation;

public class MyCacheKeyGenerator implements CacheKeyGenerator {

   @Override
   public CacheKey generateCacheKey(CacheKeyInvocationContext<? extends Annotation> ctx) {

      return new MyCacheKey(
            ctx.getAllParameters()[0].getValue()
      );
   }
}
The listed method constructs a custom key. This key is passed as part of the value generated by the first parameter of the invocation context.
To specify the custom key generation scheme, add the optional parameter cacheKeyGenerator to the @CacheResult annotation as follows:
@CacheResult(cacheKeyGenerator = MyCacheKeyGenerator.class)
public void doSomething(String p1, String p2) {
<!-- Additional configuration information here -->
}
Using the provided method, p1 contains the custom key.

24.2.4. Cache Operations

24.2.4.1. Update a Cache Entry

When the method that contains the @CachePut annotation is invoked, a parameter (normally passed to the method annotated with @CacheValue) is stored in the cache.

Example 24.12. Sample @CachePut Annotated Method

import javax.cache.annotation.CachePut;
import javax.cache.annotation.CacheKey;
import javax.cache.annotation.CacheValue;

@CachePut (cacheName = "personCache")
public void updatePerson
	(@CacheKey long personId,
	@CacheValue Person newPerson) {
<!-- Additional configuration information here -->
	}
Further customization is possible using cacheName and cacheKeyGenerator in the @CachePut method. Additionally, some parameters in the invoked method may be annotated with @CacheKey to control key generation.

24.2.4.2. Remove an Entry from the Cache

The following is an example of a @CacheRemoveEntry annotated method that is used to remove an entry from the cache:

Example 24.13. Removing an Entry from the Cache

import javax.cache.annotation.CacheRemoveEntry;
import javax.cache.annotation.CacheKey;

@CacheRemoveEntry (cacheName = "cacheOfPeople")
public void changePersonName
	(@CacheKey long personId,
	string newName {
<!-- Additional configuration information here -->
	}
The annotation accepts the optional cacheName and cacheKeyGenerator attributes.

24.2.4.3. Clear the Cache

Invoke the @CacheRemoveAll method to clear all entries from the cache.

Example 24.14. Clear All Entries from the Cache with @CacheRemoveAll

import javax.cache.annotation.CacheRemoveAll;

@CacheRemoveAll (cacheName = "statisticsCache")
public void resetStatistics() {
<!-- Additional configuration information here -->
}
As displayed in the example, this annotation accepts an optional cacheName attribute.