How to reference MWA LPN DFF Attributes in CustomListener.java fieldExited

I need to apply validations to the attributes of the LPN DFF  in CustomListener.java fieldExited

How are the LPN DFF attributes referenced?

code sample

package oracle.apps.mwa.beans;

import oracle.apps.inv.rcv.server.RcptGenPage;
import oracle.apps.inv.utilities.server.UtilFns;
import oracle.apps.mwa.eventmodel.AbortHandlerException;
import oracle.apps.mwa.eventmodel.DefaultOnlyHandlerException;
import oracle.apps.mwa.eventmodel.InterruptedHandlerException;
import oracle.apps.mwa.eventmodel.MWAEvent;
import oracle.apps.mwa.eventmodel.MWAFieldListener;

public class CustomListener implements MWAFieldListener {

    /* This method will be called for field exit in MSCA pages */
    public void fieldExited(MWAEvent e) throws AbortHandlerException,
                                               InterruptedHandlerException,
                                               DefaultOnlyHandlerException {

        UtilFns.trace("oracle.apps.mwa.beans.CustomListener. - FieldExited");