Monitoring cache elipselink L2, L1

Question

Is there a tool or software method for monitoring one, two eclipse link caches. my goal is to find out the number of objects cached for a particular class. here are some links i found but not enough:

http://www.eclipse.org/eclipselink/documentation/2.5/solutions/performance002.htm https://wiki.eclipse.org/EclipseLink/Examples/JPA/Monitoring

Answer 1

JPA does not indicate such features, however you can do this with internal EclipseLink elements, for example:

L1 (transactional cache, persistence context)

import org.eclipse.persistence.jpa.JpaEntityManager;
import org.eclipse.persistence.internal.sessions.UnitOfWorkImpl;
...
JpaEntityManager jem = em.unwrap(JpaEntityManager.class);
UnitOfWorkImpl ouw = jem.unwrap(UnitOfWorkImpl.class);
...
long count = countCachedEntitiesL1(clazz);

and the corresponding method:

// Java 7
public long countCachedEntitiesL1(Class clazz) {
    long count = 0;
    for (Map.Entry<Object, Object> entity : ouw.getCloneMapping().entrySet()) {
        if (entity.getKey().getClass().equals(clazz)) {
            count++;
        }
    }
    return count;
}

// Java 8
public long countCachedEntitiesL1(Class clazz) {
    return ouw.getCloneMapping().keySet().stream()
        .filter(entity -> entity.getClass().equals(clazz))
        .count();
}

L2 (shared cache)

import org.eclipse.persistence.jpa.JpaEntityManager;
import org.eclipse.persistence.sessions.server.ServerSession;
import org.eclipse.persistence.internal.sessions.IdentityMapAccessor;
...
JpaEntityManager jem = em.unwrap(JpaEntityManager.class);
ServerSession ss = jem.unwrap(ServerSession.class);
IdentityMapAccessor ima = (IdentityMapAccessor) ss.getIdentityMapAccessor();
...
int count = countCachedEntitiesL2(clazz);

and the corresponding method:

public int countCachedEntitiesL2(Class clazz) {
    return ima.getIdentityMap(clazz).getSize();
}