Introduction

JetCache is a Java cache abstraction which provides consistent use for various caching solutions. It provides more powerful annotation than that in Spring Cache. The annotation in JetCache supports native TTL, two level caching, and distributed automatically refreshment, also you can operate Cache instance by hand code. Presently There are four implements: RedisCache, TairCache(not open source on github), CaffeineCache (in memory), a simple LinkedHashMapCache (in memory). Full features of JetCache:

Operate cache through consistent Cache API.
Declarative method caching using annotation with TTL(Time To Live) and two level caching support
Create & configure Cache instance using annotation
Automatically collect access statistics for Cache instance and method cache
The policy of key generation and value serialization can be customized
Distributed cache automatically refreshment 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)

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Getting started

Method cache

Declare method cache using @Cached annotation.
expire = 3600 indicates that the elements will expires in 3600 seconds after put. JetCache auto generates cache key using all 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);
}

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

Automatically 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 to synchronize load operation in multi-thread environment.

Cache API

Create a Cache instance using @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, "localhost", 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 automatically refreshment:

@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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