@Override
  public String toString() {
    return "CqEvent [" + "CqName=" + cQuery.getName()
        + "; base operation=" + baseOp + "; cq operation="
        + queryOp + "; key=" + key + "; value="
        + newValue + "]";
  }
Checks if the Cq Event is for an exception. If so constructs the exception.
geode-cq/src/main/java/org/apache/geode/cache/query/cq/internal/CqEventImpl.java