Thread-Safety problem

[jingglang]

Hi,
I use your example in my project but I found emf.getCurrentTenantIdentifierResolver() always returns the same instance. It is not thread safe since multiple racing threads might change the value of MultiTenantResolver.tenantIdentifier before calling emf.createEntityManager(). So to make it thread-safe, I use synchronized method to replace MultiTenantResolver.setTenantIdentifier() method to something like:

public class MultiTenantResolver implements CurrentTenantIdentifierResolver {
...
   public synchronized EntityManager createEntityManagerWithThreadSafety(String tenantIdentifier, EntityManagerFactory emf) {
      this.tenantIdentifier = tenantIdentifier;
      return emf.createEntityManager();
   }
...
}

Please let me know if you find a problem with my solution or if you have a better solution.

Thank you for this github project and your article. It saved me a lot of hours.

[rhuan080]

Hi,

Thank you for sharing it with me. I don't see any issue with your solution. Feel free to send a PR to solve that.

Maybe to a complete solution, we can set the tenantIdentifier as volatile as well. Look at this example:

public abstract class MuiltitenancyResolver implements CurrentTenantIdentifierResolver {

    protected volatile String tenantIdentifier;

    public synchronized void setTenantIdentifier(String tenantIdentifier) {
        this.tenantIdentifier = tenantIdentifier;
    }
}

Let me know what do you think about it.