TransactionalInterceptor.java

package net.ftlines.blog.cdidemo.cdi;

import javax.inject.Inject;
import javax.interceptor.AroundInvoke;
import javax.interceptor.Interceptor;
import javax.interceptor.InvocationContext;
import javax.persistence.EntityManager;

/**
 * NB: this file is derived from the open-source project hosted at https://github.com/42Lines/blog-cdidemo
 */
@Transactional
@Interceptor
public class TransactionalInterceptor {
  @Inject
  EntityManager em;

  @AroundInvoke
  public Object wrapInTransaction(InvocationContext invocation) throws Exception {
    boolean owner = !em.getTransaction().isActive();

    if (owner) {
      em.getTransaction().begin();
    }

    try {
      return invocation.proceed();
    } catch (RuntimeException e) {
      em.getTransaction().setRollbackOnly();
      throw e;
    } finally {
      if (owner) {
        if (em.getTransaction().getRollbackOnly()) {
          em.getTransaction().rollback();
        } else {
          em.getTransaction().commit();
        }
      }
    }
  }
}