Introduction

JetCache is a Java cache abstraction which provides uniform usage for different caching solutions. It provides more powerful annotations than those in Spring Cache. The annotations in JetCache supports native TTL, two level caching, and automatically refresh in distrubuted environments, also you can manipulate Cache instance by your code. Currently, there are four implementations: RedisCache, TairCache(not open source on github), CaffeineCache (in memory) and a simple LinkedHashMapCache (in memory). Full features of JetCache:

Manipulate cache through uniform Cache API.
Declarative method caching using annotations with TTL(Time To Live) and two level caching support
Create & configure Cache instance with annotations
Automatically collect access statistics for Cache instance and method level cache
The strategy of key generation and value serialization can be customized
Distributed cache auto refresh and distributed lock. (2.2+)
Asynchronous access using Cache API (2.2+, with redis lettuce client)
Spring Boot support

requirements:

JDK1.8
Spring Framework4.0.8+ (optional, with annotation support)
Spring Boot1.1.9+ (optional)

Visit wiki for more details.

Getting started

Method cache

Declare method cache using @Cached annotation.
expire = 3600 indicates that the elements will expire in 3600 seconds after being set. JetCache automatically generates the cache key with all the parameters.

public interface UserService {
    @Cached(expire = 3600, cacheType = CacheType.REMOTE)
    User getUserById(long userId);
}

Using key attribute to specify cache key using SpEL script.

public interface UserService {
    @Cached(name="userCache-", key="#userId", expire = 3600)
    User getUserById(long userId);

    @CacheUpdate(name="userCache-", key="#user.userId", value="#user")
    void updateUser(User user);

    @CacheInvalidate(name="userCache-", key="#userId")
    void deleteUser(long userId);
}

In order to use parameter name such as key="#userId", you javac compiler target must be 1.8 and above, and the -parameters should be set. Otherwise, use index to access parameters like key="args[0]"

Auto refreshment:

public interface SummaryService{
    @Cached(expire = 3600, cacheType = CacheType.REMOTE)
    @CacheRefresh(refresh = 1800, stopRefreshAfterLastAccess = 3600, timeUnit = TimeUnit.SECONDS)
    @CachePenetrationProtect
    BigDecimal summaryOfToday(long categoryId);
}

CachePenetrationProtect annotation indicates that the cache will be loaded synchronously in multi-thread environment.

Cache API

Create a Cache instance with @CreateCache annotation:

@CreateCache(expire = 100, cacheType = CacheType.BOTH, localLimit = 50)
private Cache<Long, UserDO> userCache;

The code above create a Cache instance. cacheType = CacheType.BOTH define a two level cache (a local in-memory-cache and a remote cache system) with local elements limited upper to 50(LRU based evict). You can use it like a map:

UserDO user = userCache.get(12345L);
userCache.put(12345L, loadUserFromDataBase(12345L));
userCache.remove(12345L);

userCache.computeIfAbsent(1234567L, (key) -> loadUserFromDataBase(1234567L));

Or you can create Cache instance manually (RedisCache in this example) :

GenericObjectPoolConfig pc = new GenericObjectPoolConfig();
pc.setMinIdle(2);
pc.setMaxIdle(10);
pc.setMaxTotal(10);
JedisPool pool = new JedisPool(pc, "127.0.0.1", 6379);
Cache<Long, UserDO> userCache = RedisCacheBuilder.createRedisCacheBuilder()
                .keyConvertor(FastjsonKeyConvertor.INSTANCE)
                .valueEncoder(JavaValueEncoder.INSTANCE)
                .valueDecoder(JavaValueDecoder.INSTANCE)
                .jedisPool(pool)
                .keyPrefix("userCache-")
                .expireAfterWrite(200, TimeUnit.SECONDS)
                .buildCache();

Advanced API

Asynchronous API:

CacheGetResult r = cache.GET(userId);
CompletionStage<ResultData> future = r.future();
future.thenRun(() -> {
    if(r.isSuccess()){
        System.out.println(r.getValue());
    }
});

Distributed lock:

cache.tryLockAndRun("key", 60, TimeUnit.SECONDS, () -> heavyDatabaseOperation());

Read through and auto refresh:

@CreateCache
@CacheRefresh(timeUnit = TimeUnit.MINUTES, refresh = 60, stopRefreshAfterLastAccess = 100)
@CachePenetrationProtect
private Cache<String, Long> orderSumCache;

@PostConstruct
public void init(){
    orderSumCache.config().setLoader(this::loadOrderSumFromDatabase);
}

Configuration with Spring Boot

pom:

<dependency>
    <groupId>com.alicp.jetcache</groupId>
    <artifactId>jetcache-starter-redis</artifactId>
    <version>${jetcache.latest.version}</version>
</dependency>

App class:

@SpringBootApplication
@EnableMethodCache(basePackages = "com.company.mypackage")
@EnableCreateCacheAnnotation
public class MySpringBootApp {
    public static void main(String[] args) {
        SpringApplication.run(MySpringBootApp.class);
    }
}

spring boot application.yml config:

jetcache:
  statIntervalMinutes: 15
  areaInCacheName: false
  local:
    default:
      type: linkedhashmap
      keyConvertor: fastjson
      limit: 100
  remote:
    default:
      type: redis
      keyConvertor: fastjson
      valueEncoder: java
      valueDecoder: java
      poolConfig:
        minIdle: 5
        maxIdle: 20
        maxTotal: 50
      host: ${redis.host}
      port: ${redis.port}

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