else if (propDef.getPropertyType().equals(PropertyType.ID))
return new PropertyIdImpl(propDef.getId(), (String) null);
else if (propDef.getPropertyType().equals(PropertyType.INTEGER))
return new PropertyIntegerImpl(propDef.getId(), (BigInteger) null);
else if (propDef.getPropertyType().equals(PropertyType.STRING))
return new PropertyStringImpl(propDef.getId(), (String) null);
else if (propDef.getPropertyType().equals(PropertyType.URI))
return new PropertyUriImpl(propDef.getId(), (String) null);
else
return null;
}