Is there a way to make eclipselink/JPA use redis for saving and retrieving peristence-unit level (L2) cache?

Question

I'm setting up a cluster environment and I want my JPA's second level cache to be replicated throughout the cluster's nodes. I'm using eclipselink as JPA provider and redis for cache management.

Answer 1

There is no official or community project that support it.

However, you can implement your own CacheInterceptor.

Eg.

import org.eclipse.persistence.descriptors.ClassDescriptor;
import org.eclipse.persistence.internal.identitymaps.CacheKey;
import org.eclipse.persistence.internal.identitymaps.IdentityMap;
import org.eclipse.persistence.internal.sessions.AbstractSession;
import org.eclipse.persistence.sessions.interceptors.CacheInterceptor;
import org.eclipse.persistence.sessions.interceptors.CacheKeyInterceptor;
import java.util.Map;

public class MyRedisCacheInterceptor extends CacheInterceptor {

    private final MyCacheProvider cacheSupport;
    private final String cacheName;

    public DefaultCacheInterceptor(IdentityMap targetIdentityMap, AbstractSession interceptedSession,
                                   String cacheName, DefaultCacheSupport cacheSupport) {
        super(targetIdentityMap, interceptedSession);
        this.cacheSupport = cacheSupport;
        this.cacheName = cacheName;
    }

    @Override
    public Object clone() {
        return null;
    }

    @Override
    protected CacheKeyInterceptor createCacheKeyInterceptor(CacheKey wrappedCacheKey) {
        final long longKey = (long) wrappedCacheKey.getKey();

        CacheKeyInterceptor newKey = new CacheKeyInterceptor(wrappedCacheKey) {
            @Override
            public Object getObject() {
                return cacheSupport.getOrCreateCache(cacheName).get(longKey);
            }

            @Override
            public void setObject(Object object) {
                cacheSupport.getOrCreateCache(cacheName).put(longKey, object);
            }
        };

        return newKey;
    }

    @Override
    public boolean containsKey(Object primaryKey) {
        return cacheSupport.getOrCreateCache(cacheName).containsKey(primaryKey);
    }

    @Override
    public Map<Object, Object> getAllFromIdentityMapWithEntityPK(Object[] pkList, ClassDescriptor descriptor, AbstractSession session) {
        return null;
    }

    @Override
    public Map<Object, CacheKey> getAllCacheKeysFromIdentityMapWithEntityPK(Object[] pkList, ClassDescriptor descriptor, AbstractSession session) {
        return null;
    }

    @Override
    public void release() {
    }
}

You can take a look to this project that uses Apache Ignite, replace it with Redis and try. sample project

Cache Interceptor Impl: Sample cache interceptor impl

Ignite Cache Interceptor: Sample Ignite cache interceptor project

Other sample project with Hazelcast: Sample Hazelcast cache interceptor project

In short, If you need to use Redis as a second level cache you need to implement your own customization or maybe Hibernate is your best choice. It has a redisson-hibernate cache provider that you can plug (redisson-hibernate).

Regards,