public Object invoke(Invocation mi) throws Exception 
{
      // We are going to work with the context a lot
      EntityEnterpriseContext ctx = (EntityEnterpriseContext) mi.getEnterpriseContext();
      boolean nonReentrant = !(reentrant || isReentrantMethod(mi));
      // Not a reentrant method like getPrimaryKey
      NonReentrantLock methodLock = ctx.getMethodLock();
      Transaction miTx = ctx.getTransaction();
      boolean locked = false;
      try
      {
         while (!locked)
         {
            if (methodLock.attempt(5000, miTx, nonReentrant))
            {
               locked = true;
            }
            else
            {
               if (isTxExpired(miTx))
               {
                  log.error("Saw rolled back tx=" + miTx);
                  throw new RuntimeException("Transaction marked for rollback, possibly a timeout");
               }
            }
         }
      }
      catch (NonReentrantLock.ReentranceException re)
      {
         if (mi.getType() == InvocationType.REMOTE)
         {
            throw new RemoteException("Reentrant method call detected: "
                    + container.getBeanMetaData().getEjbName() + " "
                    + ctx.getId().toString());
         }
         else
         {
            throw new EJBException("Reentrant method call detected: "
                    + container.getBeanMetaData().getEjbName() + " "
                    + ctx.getId().toString());
         }
      }
      try
      {
         ctx.lock();
         return getNext().invoke(mi);
      }
      finally
      {
         ctx.unlock();
         methodLock.release(nonReentrant);
      }
}

 protected boolean isReentrantMethod(Invocation mi) 
{
      try
      {
         Class[] noArg = new Class[0];
         getEJBHome = EJBObject.class.getMethod("getEJBHome", noArg);
         getHandle = EJBObject.class.getMethod("getHandle", noArg);
         getPrimaryKey = EJBObject.class.getMethod("getPrimaryKey", noArg);
         isIdentical = EJBObject.class.getMethod("isIdentical", new Class[]{EJBObject.class});
         remove = EJBObject.class.getMethod("remove", noArg);
      }
      catch (Exception e)
      {
         e.printStackTrace();
         throw new ExceptionInInitializerError(e);
      }
      // is this a known non-entrant method
      Method m = mi.getMethod();
      if (m != null && (
              m.equals(getEJBHome) ||
              m.equals(getHandle) ||
              m.equals(getPrimaryKey) ||
              m.equals(isIdentical) ||
              m.equals(remove)))
      {
         return true;
      }
      // if this is a non-entrant message to the container let it through
      if (mi instanceof CMRInvocation)
      {
         Entrancy entrancy = ((CMRInvocation) mi).getEntrancy();
         if (entrancy == Entrancy.NON_ENTRANT)
         {
            log.trace("NON_ENTRANT invocation");
            return true;
         }
      }
      return false;
}

 protected boolean isTxExpired(Transaction miTx) throws Exception 
{
      if (miTx != null && miTx.getStatus() == Status.STATUS_MARKED_ROLLBACK)
      {
         return true;
      }
      return false;
}

 public  void setContainer(Container container) 
{
   // Public --------------------------------------------------------
      super.setContainer(container);
      if (container != null)
      {
         EntityMetaData meta = (EntityMetaData) container.getBeanMetaData();
         reentrant = meta.isReentrant();
      }
}