Simple CacheStore using Guava Cache

CacheStore.java

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.annotation.PostConstruct;
import java.util.Optional;
import java.util.concurrent.TimeUnit;

@Component
public class CacheStore {

    private static final Logger LOGGER = LoggerFactory.getLogger(CacheStore.class);

    private Cache<String, ExpensiveObject> cache;

    @PostConstruct
    public void initCache() {
        /**
         * Desafio aqui eh encontrar politica de cache no workload real para:
         * 1. maximizar o cache-hit, ideal +90%
         * 2. diminuir os ciclos de GC (minors e principalmente fulls)
         * 3. permitir funcionamento normal da app e picos de acessos
         */
        this.cache = CacheBuilder.newBuilder()
                        .maximumSize(100_000)
                        .expireAfterWrite(1, TimeUnit.DAYS)
                        .build();
    }

    public Optional<ExpensiveObject> get(String id) {
        ExpensiveObject object = cache.getIfPresent(id);
        return Optional.ofNullable(object);
    }
  
    public void update(String id, ExpensiveObject object) {
        LOGGER.info("[CACHE] Putting key '{}' in cache", id);
        cache.put(id, object);
    }

    public void remove(String id) {
        LOGGER.info("[CACHE] Removing key '{}' from cache", id);
        this.cache.invalidate(id);
    }
}

pom.xml

<dependency>
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>
  <version>31.0.1-jre</version>
</dependency>

• Cache using ConcurrentHashMap
• To implement Java local caching, start from these points

We can use this new lib, ExpiringMap: A high performance, low-overhead, zero dependency, thread-safe ConcurrentMap implementation that expires entries.

ExpiringMap allows you to create a map that expires entries after a certain time period or when a maximum map size has been exceeded:

Map<String, Connection> map = ExpiringMap.builder()
  .maxSize(123)
  .expiration(30, TimeUnit.SECONDS)
  .build();
  
// Expires after 30 seconds or as soon as a 124th element is added and this is the next one to expire based on the expiration policy
map.put("connection", connection);