Skip to main content

3B.Hazelcast Middleware

trydoforOriginalSlardarCachingEventAbout 1 min

3B.Hazelcast Middleware

Using hazelcast as session, cache and messaging middleware, including,

  • spring session - Hazelcast4IndexedSessionRepository
  • server cache - WingsHazelcast
  • global lock - HazelcastGlobalLock
  • global event - HazelcastSyncPublisher
  • snowflake id - FlakeIdHazelcastImpl

3B.1.Default Configuration

  • ClassNotFound - user-code-deployment must be set
  • Reconnection mechanism, set the reconnection time on the client side
  • Data persistence, the community version requires DIY MapStore and MapLoader
  • Multicast is enabled by default, address is 224.0.0.1

In the actual, it is recommended to deploy hazelcast cluster independently and use the client to connect. Cluster configuration should be app+1, so that at least one survives.

Generally in the same network, you can use multicast between intranets, but it is recommended to use the tcp-ip method of networking. Choose a different configuration file via spring.hazelcast.config, xml is recommended.

hazelcast 3 and 4 are very different and are not compatible in SpringBoot 2.2 and 2.4.

3B.2.Distributed Lock

Hazelcast provides 3 types of locks, CP system is recommended, but the cluster needs at least 3 units, the default 0 is single unsafe mode.

  • FencedLock - Raft's distributed lock, in CP system (4.x)
  • IMap.lock - automatic GC, clean and simple
  • ILock.lock - follow j.u.c.Lock convention (removed in 3.12)

Different projects need to set cluster-name separately to avoid interference from caches with the same name in different projects. slardar uses the default springboot configuration, the client and server configuration files are as follows.

  • extra-conf/hazelcast-client.xml
  • extra-conf/hazelcast-server.xml

If independent customization is required, the ClientConfig or Config bean can be exposed programmatically, See the following.

3B.3.Distributed Cache

Implement ServerCacheManager with hazelcast through hazelcastCacheManager

For hazelcast's MapConfig, if there is no configuration, wings will automatically configure the following MapConf according to the level.

<time-to-live-seconds>3600</time-to-live-seconds>
<max-idle-seconds>0</max-idle-seconds>
<eviction size="5000"/>

3B.4.Message Subscription

Hazelcast's topic (#HazelcastTopic) is wrapped in the SpringEvent pattern for easy navigation between code in the IDE, and

  • What producers/publishers does the Event has
  • What consumers/subscribers the Event has