* @throws PropertyException For invalid parameters.
*/
public DtLengthBPIPDirection(final PropertyValue bpdLength,
final PropertyValue ipdLength) throws PropertyException {
if (! bpdLength.canEvalLength()) {
throw new PropertyException("BPD must evaluate to a length.");
}
if (! ipdLength.canEvalLength()) {
throw new PropertyException("IPD must evaluate to a length.");
}
this.bpdLength = bpdLength;
this.ipdLength = ipdLength;
}