[[cdi_support]]
==  CDI Support
{brandname} includes integration with link:http://www.cdi-spec.org[Contexts and Dependency Injection (better known as CDI)] via {brandname}'s `infinispan-cdi-embedded` or `infinispan-cdi-remote` module.
CDI is part of link:http://www.oracle.com/technetwork/java/javaee/tech/index-jsp-142185.html[Java EE specification] and aims for managing beans' lifecycle inside the container.
The integration allows to inject Cache interface and bridge Cache and CacheManager events. JCache annotations (JSR-107) are supported by `infinispan-jcache` and `infinispan-jcache-remote` artifacts. For more information have a look at link:http://download.oracle.com/otndocs/jcp/jcache-1_0-fr-spec/index.html[Chapter 11] of the JCACHE specification.

[[maven_dependencies]]
=== Maven Dependencies
To include CDI support for {brandname} in your project, use one of the following dependencies:

.pom.xml for Embedded mode
include::topics/dependencies/cdi_embedded.adoc[]

.pom.xml for Remote mode
include::topics/dependencies/cdi_remote.adoc[]

.Which version of {brandname} should I use?
TIP: We recommend using the latest final version {brandname}.

=== Embedded cache integration
==== Inject an embedded cache
By default you can inject the default {brandname} cache. Let's look at the following example:

.Default cache injection
[source,java]
----

...
import javax.inject.Inject;

public class GreetingService {

    @Inject
    private Cache<String, String> cache;

    public String greet(String user) {
        String cachedValue = cache.get(user);
        if (cachedValue == null) {
            cachedValue = "Hello " + user;
            cache.put(user, cachedValue);
        }
        return cachedValue;
    }
}

----

If you want to use a specific cache rather than the default one, you just have to provide your own cache configuration and cache qualifier. See example below:

.Qualifier example
[source,java]
----

...
import javax.inject.Qualifier;

@Qualifier
@Target({ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface GreetingCache {
}

----

.Injecting Cache with qualifier
[source,java]
----

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

public class Config {

    @ConfigureCache("greeting-cache") // This is the cache name.
    @GreetingCache // This is the cache qualifier.
    @Produces
    public Configuration greetingCacheConfiguration() {
        return new ConfigurationBuilder()
                    .memory()
                        .size(1000)
                    .build();
    }

    // The same example without providing a custom configuration.
    // In this case the default cache configuration will be used.
    @ConfigureCache("greeting-cache")
    @GreetingCache
    @Produces
    public Configuration greetingCacheConfiguration;
}

----

To use this cache in the GreetingService add the `@GeetingCache` qualifier on your cache injection point.

==== Override the default embedded cache manager and configuration
You can override the default cache configuration used by the default `EmbeddedCacheManager`. For that, you just have to create a `Configuration` producer with default qualifiers as illustrated in the following snippet:

.Overriding Configuration
[source,java]
----

public class Config {

    // By default CDI adds the @Default qualifier if no other qualifier is provided.
    @Produces
    public Configuration defaultEmbeddedCacheConfiguration() {
        return new ConfigurationBuilder()
                    .memory()
                        .size(100)
                    .build();
    }
}

----

It's also possible to override the default `EmbeddedCacheManager`.
The newly created manager must have default qualifiers and Application scope.

.Overriding EmbeddedCacheManager
[source,java]
----

...
import javax.enterprise.context.ApplicationScoped;

public class Config {

    @Produces
    @ApplicationScoped
    public EmbeddedCacheManager defaultEmbeddedCacheManager() {
      return new DefaultCacheManager(new ConfigurationBuilder()
                                          .memory()
                                              .size(100)
                                          .build());
   }
}

----

==== Configure the transport for clustered use
To use {brandname} in a clustered mode you have to configure the transport with the `GlobalConfiguration`.
To achieve that override the default cache manager as explained in the previous section. Look at the following snippet:

.Overriding default EmbeddedCacheManager
[source,java]
----

...
package org.infinispan.configuration.global.GlobalConfigurationBuilder;

@Produces
@ApplicationScoped
public EmbeddedCacheManager defaultClusteredCacheManager() {
    return new DefaultCacheManager(
        new GlobalConfigurationBuilder().transport().defaultTransport().build(),
        new ConfigurationBuilder().memory().size(7).build()
    );
}

----

=== Remote cache integration

==== Inject a remote cache
With the CDI integration it's also possible to use a `RemoteCache` as illustrated in the following snippet:

.Injecting RemoteCache
[source,java]
----

public class GreetingService {

    @Inject
    private RemoteCache<String, String> cache;

    public String greet(String user) {
        String cachedValue = cache.get(user);
        if (cachedValue == null) {
            cachedValue = "Hello " + user;
            cache.put(user, cachedValue);
        }
        return cachedValue;
    }
}

----

If you want to use another cache, for example the greeting-cache, add the `@Remote` qualifier on the cache injection point which contains the cache name.

.Injecting RemoteCache with qualifier
[source,java]
----

public class GreetingService {

    @Inject
    @Remote("greeting-cache")
    private RemoteCache<String, String> cache;

    ...
}

----

Adding the `@Remote` cache qualifier on each injection point might be error prone.
That's why the remote cache integration provides another way to achieve the same goal. For that you have to create your own qualifier annotated with `@Remote`:

.RemoteCache qualifier
[source,java]
----

@Remote("greeting-cache")
@Qualifier
@Target({ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RemoteGreetingCache {
}

----

To use this cache in the GreetingService add the qualifier `@RemoteGreetingCache` qualifier on your cache injection.

==== Override the default remote cache manager
Like the embedded cache integration, the remote cache integration comes with a default remote cache manager producer. This default `RemoteCacheManager` can be overridden as illustrated in the following snippet:

.Overriding default RemoteCacheManager
[source,java]
----

public class Config {

    @Produces
    @ApplicationScoped
    public RemoteCacheManager defaultRemoteCacheManager() {
        return new RemoteCacheManager(localhost, 1544);
    }
}

----

=== Use a custom remote/embedded cache manager for one or more cache
It's possible to use a custom cache manager for one or more cache. You just need to annotate the cache manager producer with the cache qualifiers. Look at the following example:

[source,java]
----

public class Config {

   @GreetingCache
   @Produces
   @ApplicationScoped
   public EmbeddedCacheManager specificEmbeddedCacheManager() {
      return new DefaultCacheManager(new ConfigurationBuilder()
                                          .expiration()
                                              .lifespan(60000l)
                                          .build());
   }

   @RemoteGreetingCache
   @Produces
   @ApplicationScoped
   public RemoteCacheManager specificRemoteCacheManager() {
       return new RemoteCacheManager("localhost", 1544);
   }
}

----

With the above code the GreetingCache or the RemoteGreetingCache will be associated with the produced cache manager.

.Producer method scope
NOTE: To work properly the producers must have the scope @ApplicationScoped . Otherwise each injection of cache will be associated to a new instance of cache manager.

=== Use JCache caching annotations

TIP: There is now a separate module for JSR 107 (JCACHE) integration, including API. See link:#jcache_jsr_107[this chapter] for details.

When CDI integration and JCache artifacts are present on the classpath, it is possible to use JCache annotations with CDI managed beans.
These annotations provide a simple way to handle common use cases.
The following caching annotations are defined in this specification:

* `@CacheResult` - caches the result of a method call
* `@CachePut` - caches a method parameter
* `@CacheRemoveEntry` - removes an entry from a cache
* `@CacheRemoveAll` - removes all entries from a cache

.Annotations target type
WARNING: These annotations must only be used on methods.

To use these annotations, proper interceptors need to be declared in `beans.xml` file:

.Interceptors for managed environments such as Application Servers
[source,xml]
----
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
   version="1.2" bean-discovery-mode="annotated">

  <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>
----

.Interceptors for unmanaged environments such as standalone applications
[source,xml]
----
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
   version="1.2" bean-discovery-mode="annotated">

  <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>
----

The following snippet of code illustrates the use of `@CacheResult` annotation. As you can see it simplifies the caching of the `Greetingservice#greet` method results.

.Using JCache annotations
[source,java]
----

import javax.cache.interceptor.CacheResult;

public class GreetingService {

    @CacheResult
    public String greet(String user) {
        return "Hello" + user;
    }
}

----

The first version of the `GreetingService` and the above version have exactly the same behavior. The only difference is the cache used. By default it's the fully qualified name of the annotated method with its parameter types (e.g. `org.infinispan.example.GreetingService.greet(java.lang.String)`).

Using other cache than default is rather simple. All you need to do is to specify its name with the `cacheName` attribute of the cache annotation. For example:

.Specifying cache name for JCache
[source,java]
----

@CacheResult(cacheName = "greeting-cache")

----

=== Use Cache events and CDI

It is possible to receive Cache and Cache Manager level events using CDI Events. You can achieve it using `@Observes` annotation as shown in the following snippet:

.Event listeners based on CDI
[source,java]
----

import javax.enterprise.event.Observes;
import org.infinispan.notifications.cachemanagerlistener.event.CacheStartedEvent;
import org.infinispan.notifications.cachelistener.event.*;

public class GreetingService {

    // Cache level events
    private void entryRemovedFromCache(@Observes CacheEntryCreatedEvent event) {
        ...
    }

    // Cache Manager level events
    private void cacheStarted(@Observes CacheStartedEvent event) {
        ...
    }
}

----

TIP: Check link:#listeners_and_notifications[Listeners and Notifications] for more information about event types.
