To convert a temperature measurement value in degrees F to degrees K, apply
* the formula:
* value in K = (value in F + unitOffset) * unitFactor
*
Inversely, to convert a measurement from the SI unit (K) to this unit (F),
* apply this formula:
* value in F = (value in K) / unitFactor - unitOffset
*
So far temperature is the only dimension that requires an offset. All * the other dimensions only require a multiplication * factor, so their offset is always zero. For example, * To represent the position dimension units in kilometers (km):
*The SI unit for position is meters (m) so the kilometers unitFactor is 1000.0 * and there is zero offset.
*
This class is an infinite concept so that an arbitrary number of different * unit measurements can be represented for any physical dimension. All that is * required is specify the name of units and the multiplication factor and offset * needed to convert the unit to the SI unit for that dimension.
@see BaseDimensionRepresentativeConcept @author Charles Shelton @version $Id: BaseUnitConcept.java 70398 2014-10-22 23:44:32Z cxh $ @since Ptolemy II 10.0 @Pt.ProposedRating Red (cshelton) @Pt.AcceptedRating Red (cshelton) */ public class BaseUnitConcept extends UnitConcept { /////////////////////////////////////////////////////////////////// //// public constructors/factories //// /** Create a new base unit concept, belonging to the given * ontology, with an automatically generated name. * * @param ontology The ontology to which this concept belongs. * @param representative The finite concept that represents where the infinite * token concepts belong in the ontology lattice. * @param unitInfo The token value for this BaseUnitConcept. * @return The newly created RecordConcept. * @exception IllegalActionException If the base class throws it. */ public static BaseUnitConcept createBaseUnitConcept(Ontology ontology, BaseDimensionRepresentativeConcept representative, RecordToken unitInfo) throws IllegalActionException { try { return new BaseUnitConcept(ontology, representative, unitInfo); } catch (NameDuplicationException e) { throw new IllegalActionException( "Name conflict with automatically generated infinite concept name.\n" + "This should never happen." + "Original exception:" + e.toString()); } } /////////////////////////////////////////////////////////////////// //// protected constructors //// /** Create a new BaseUnitConcept, belonging to the given * ontology. * * @param ontology The ontology to which this concept belongs. * @param representative The finite concept that represents the physical * dimension for the set infinite concepts that represent units for * this dimension in the ontology lattice. * @param unitInfo The record token value that has the name and scale * factor information for this unit. * @exception NameDuplicationException Should never be thrown. * @exception IllegalActionException If the base class throws it. */ protected BaseUnitConcept(Ontology ontology, BaseDimensionRepresentativeConcept representative, RecordToken unitInfo) throws IllegalActionException, NameDuplicationException { super(ontology, representative, unitInfo); Token unitFactor = unitInfo.get(UnitConversionInfo.unitFactorLabel); if (unitFactor instanceof ScalarToken) { _unitFactor = (ScalarToken) unitFactor; } else { throw new IllegalActionException(this, "Invalid unit factor value (must be a scalar value): " + unitFactor); } Token unitOffset = unitInfo.get(UnitConversionInfo.unitOffsetLabel); if (unitOffset == null) { _unitOffset = DoubleToken.ZERO; } else if (unitOffset instanceof ScalarToken) { _unitOffset = (ScalarToken) unitOffset; } else { throw new IllegalActionException(this, "Invalid unit offset value (must be a scalar value): " + unitOffset); } } }