@Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        final UnsuccessDelivery other = (UnsuccessDelivery)obj;
        if (destinationAddress == null) {
            if (other.destinationAddress != null)
                return false;
        } else if (!destinationAddress.equals(other.destinationAddress))
            return false;
        if (errorStatusCode != other.errorStatusCode)
            return false;
        return true;
    }