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Adding Caching to Spring

As of version 3.1, Spring Framework provides support for adding caching into an existing Spring application. Spring 3.2 and later versions support JCache compliant caching providers. You can also use JCache caching backed by Hazelcast if your Spring version supports JCache.

Declarative Spring Cache Configuration

<cache:annotation-driven cache-manager="cacheManager" />

<hz:hazelcast id="instance">
    ...
</hz:hazelcast>

<bean id="cacheManager" class="com.hazelcast.spring.cache.HazelcastCacheManager">
    <constructor-arg ref="instance"/>
</bean>

Hazelcast uses its Map implementation for underlying cache. You can configure a map with your cache’s name if you want to set additional configuration such as ttl.

<cache:annotation-driven cache-manager="cacheManager" />

<hz:hazelcast id="instance">
    <hz:config>
        ...

        <hz:map name="city" time-to-live-seconds="0" in-memory-format="BINARY" />
    </hz:config>
</hz:hazelcast>

<bean id="cacheManager" class="com.hazelcast.spring.cache.HazelcastCacheManager">
    <constructor-arg ref="instance"/>
</bean>
public interface IDummyBean {
    @Cacheable("city")
    String getCity();
}

Defining Timeouts for Cache Read Operation

You can define a timeout value for the get operations from your Spring cache. This may be useful for some cases, such as SLA requirements. Hazelcast provides a property to specify this timeout: hazelcast.spring.cache.prop. This can be specified as a Java property (using -D) or you can add this property to your Spring properties file (usually named as application.properties).

An example usage is given below:

hazelcast.spring.cache.prop=defaultReadTimeout=2,cache1=10,cache2=20

The argument defaultReadTimeout applies to all your Spring caches. If you want to define different timeout values for some specific Spring caches, you can provide them as a comma separated list as shown in the above example usage. The values are in milliseconds. If you want to have no timeout for a cache, simply set it to 0 or a negative value.

Declarative Hazelcast JCache Based Caching Configuration

<cache:annotation-driven cache-manager="cacheManager" />

<hz:hazelcast id="instance">
    ...
</hz:hazelcast>

<hz:cache-manager id="hazelcastJCacheCacheManager" instance-ref="instance" name="hazelcastJCacheCacheManager"/>

<bean id="cacheManager" class="org.springframework.cache.jcache.JCacheCacheManager">
    <constructor-arg ref="hazelcastJCacheCacheManager" />
</bean>

You can use JCache implementation in both member and client mode. A cache manager should be bound to an instance. Instance can be referenced by instance-ref attribute or provided by hazelcast.instance.name property which is passed to CacheManager. Instance should be specified using one of these methods.

Instance name provided in properties overrides instance-ref attribute.

You can specify an URI for each cache manager with uri attribute.

<hz:cache-manager id="cacheManager2" name="cacheManager2" uri="testURI">
    <hz:properties>
        <hz:property name="hazelcast.instance.name">named-spring-hz-instance</hz:property>
        <hz:property name="testProperty">testValue</hz:property>
    </hz:properties>
</hz:cache-manager>

Annotation-Based Spring Cache Configuration

Annotation-Based Configuration does not require any XML definition. To perform Annotation-Based Configuration:

  • Implement a CachingConfiguration class with related Annotations.

    @Configuration
    @EnableCaching
    public class CachingConfiguration extends CachingConfigurerSupport {
        @Bean
        public CacheManager cacheManager() {
            ClientConfig config = new ClientConfig();
            HazelcastInstance client = HazelcastClient.newHazelcastClient(config);
            return new com.hazelcast.spring.cache.HazelcastCacheManager(client);
        }
        @Bean
        public KeyGenerator keyGenerator() {
            return null;
        }
    }
  • Launch Application Context and register CachingConfiguration.

    AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
    context.register(CachingConfiguration.class);
    context.refresh();

For more information about Spring Cache, see Spring Cache Abstraction.