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The NetCDF-Java Library is a Java interface to NetCDF files,
as well as to many other types of scientific data formats.
// $Id: OffsetUnit.java 64 2006-07-12 22:30:50Z edavis $
/*
* Copyright 1998-2009 University Corporation for Atmospheric Research/Unidata
*
* Portions of this software were developed by the Unidata Program at the
* University Corporation for Atmospheric Research.
*
* Access and use of this software shall impose the following obligations
* and understandings on the user. The user is granted the right, without
* any fee or cost, to use, copy, modify, alter, enhance and distribute
* this software, and any derivative works thereof, and its supporting
* documentation for any purpose whatsoever, provided that this entire
* notice appears in all copies of the software, derivative works and
* supporting documentation. Further, UCAR requests that the user credit
* UCAR/Unidata in any publications that result from the use of this
* software or in any product that includes this software. The names UCAR
* and/or Unidata, however, may not be used in any advertising or publicity
* to endorse or promote any products or commercial entity unless specific
* written permission is obtained from UCAR/Unidata. The user also
* understands that UCAR/Unidata is not obligated to provide the user with
* any support, consulting, training or assistance of any kind with regard
* to the use, operation and performance of this software nor to provide
* the user with any updates, revisions, new versions or "bug fixes."
*
* THIS SOFTWARE IS PROVIDED BY UCAR/UNIDATA "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL UCAR/UNIDATA BE LIABLE FOR ANY SPECIAL,
* INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE ACCESS, USE OR PERFORMANCE OF THIS SOFTWARE.
*/
package ucar.units;
/**
* Provides support for units that are offset from reference units (ex: as the
* unit "degree Celsius" is offset from the reference unit "kelvin"). Instances
* of this class are immutable.
*
* @author Steven R. Emmerson
* @version $Id: OffsetUnit.java 64 2006-07-12 22:30:50Z edavis $
*/
public final class OffsetUnit extends UnitImpl implements DerivableUnit {
private static final long serialVersionUID = 1L;
/**
* The origin of this unit in terms of the reference unit.
*
* @serial
*/
private final double _offset;
/**
* The reference unit.
*
* @serial
*/
private final Unit _unit;
/**
* The derived unit that is convertible with this unit.
*
* @serial
*/
private DerivedUnit _derivedUnit;
/**
* Constructs from a reference unit and an offset.
*
* @param unit
* The reference unit.
* @param offset
* The origin of this unit in terms of the reference unit. For
* example, a degree Celsius unit would be created as "new
* OffsetUnit(kelvin, 273.15).
*/
public OffsetUnit(final Unit unit, final double offset) {
this(unit, offset, null);
}
/**
* Constructs from a reference unit, and offset, and a unit identifier.
*
* @param unit
* The reference unit.
* @param offset
* The origin of this unit in terms of the reference unit. For
* example, a degree Celsius unit would be created as "new
* OffsetUnit(kelvin, 273.15).
* @param id
* The identifier for the new unit.
*/
public OffsetUnit(final Unit unit, final double offset, final UnitName id) {
super(id);
if (!(unit instanceof OffsetUnit)) {
_unit = unit;
_offset = offset;
}
else {
_unit = ((OffsetUnit) unit)._unit;
_offset = ((OffsetUnit) unit)._offset + offset;
}
}
static Unit getInstance(final Unit unit, final double origin) {
return (origin == 0)
? unit
: new OffsetUnit(unit, origin);
}
/**
* Returns the reference unit.
*
* @return The reference unit.
*/
public Unit getUnit() {
return _unit;
}
/**
* Returns the offset. The offset is the location of the origin of this unit
* in terms of the reference unit.
*
* @return The origin of this unit in terms of the reference unit.
*/
public double getOffset() {
return _offset;
}
/*
* From UnitImpl:
*/
/**
* Clones this unit, changing the identifier.
*
* @param id
* The identifier for the new unit.
* @return This unit with its identifier changed.
*/
public Unit clone(final UnitName id) {
return new OffsetUnit(getUnit(), getOffset(), id);
}
@Override
public Unit multiplyBy(final double scale) throws MultiplyException {
if (scale == 0) {
throw new MultiplyException(scale, this);
}
return getInstance(_unit.multiplyBy(scale), _offset / scale);
}
@Override
public Unit shiftTo(final double origin) {
return getInstance(_unit, origin + _offset);
}
/**
* Multiply this unit by another unit.
*
* @param that
* The unit to multiply this unit by.
* @return The product of this unit and that. The offset of
* this unit will be ignored; thus, for example
* "celsius.myMultiplyBy(day)" is equivalent to
* "kelvin.myMultiplyBy(day)".
* @throws MultiplyException
* Can't multiply these units together.
*/
@Override
protected Unit myMultiplyBy(final Unit that) throws MultiplyException {
return that instanceof OffsetUnit
? getUnit().multiplyBy(((OffsetUnit) that).getUnit())
: getUnit().multiplyBy(that);
}
/**
* Divide this unit by another unit.
*
* @param that
* The unit to divide this unit by.
* @return The quotient of this unit and that. The offset of
* this unit will be ignored; thus, for example
* "celsius.myDivideBy(day)" is equivalent to
* "kelvin.myDivideBy(day)".
* @throws OperationException
* Can't divide these units.
*/
@Override
protected Unit myDivideBy(final Unit that) throws OperationException {
return that instanceof OffsetUnit
? getUnit().divideBy(((OffsetUnit) that).getUnit())
: getUnit().divideBy(that);
}
/**
* Divide this unit into another unit.
*
* @param that
* The unit to divide this unit into.
* @return The quotient of that unit and this unit. The offset
* of this unit will be ignored; thus, for example
* "celsius.myDivideInto(day)" is equivalent to
* "kelvin.myDivideInto(day)".
* @throws OperationException
* Can't divide these units.
*/
@Override
protected Unit myDivideInto(final Unit that) throws OperationException {
return that instanceof OffsetUnit
? getUnit().divideInto(((OffsetUnit) that).getUnit())
: getUnit().divideInto(that);
}
/**
* Raise this unit to a power.
*
* @param power
* The power to raise this unit by.
* @return The result of raising this unit by the power power.
* The offset of this unit will be ignored; thus, for example
* "celsius.myRaiseTo(2)" is equivalent to "kelvin.myRaiseTo(2)".
* @throws RaiseException
* Can't raise this unit to a power.
*/
// Ignore offset (e.g. "Cel2" == "K2")
@Override
protected Unit myRaiseTo(final int power) throws RaiseException {
return getUnit().raiseTo(power);
}
/**
* Returns the derived unit that is convertible with this unit.
*
* @return The derived unit that is convertible with this unit.
*/
public DerivedUnit getDerivedUnit() {
if (_derivedUnit == null) {
_derivedUnit = getUnit().getDerivedUnit();
}
return _derivedUnit;
}
/**
* Converts a value in this unit to the equivalent value in the convertible
* derived unit.
*
* @param amount
* The value in this unit.
* @return The equivalent value in the convertible derived unit.
* @throws ConversionException
* Can't convert between units.
*/
public float toDerivedUnit(final float amount) throws ConversionException {
return (float) toDerivedUnit((double) amount);
}
/**
* Converts a value in this unit to the equivalent value in the convertible
* derived unit.
*
* @param amount
* The value in this unit.
* @return The equivalent value in the convertible derived unit.
* @throws ConversionException
* Can't convert between units.
*/
public double toDerivedUnit(final double amount) throws ConversionException {
if (!(_unit instanceof DerivableUnit)) {
throw new ConversionException(this, getDerivedUnit());
}
return ((DerivableUnit) getUnit()).toDerivedUnit(amount + getOffset());
}
/**
* Converts values in this unit to the equivalent values in the convertible
* derived unit.
*
* @param input
* The values in this unit.
* @param output
* The equivalent values in the convertible derived unit. May be
* the same array as input.
* @return output.
* @throws ConversionException
* Can't convert between units.
*/
public float[] toDerivedUnit(final float[] input, final float[] output)
throws ConversionException {
if (!(_unit instanceof DerivableUnit)) {
throw new ConversionException(this, getDerivedUnit());
}
final float origin = (float) getOffset();
for (int i = input.length; --i >= 0;) {
output[i] = input[i] + origin;
}
return ((DerivableUnit) getUnit()).toDerivedUnit(output, output);
}
/**
* Converts values in this unit to the equivalent values in the convertible
* derived unit.
*
* @param input
* The values in this unit.
* @param output
* The equivalent values in the convertible derived unit. May be
* the same array as input.
* @return output.
* @throws ConversionException
* Can't convert between units.
*/
public double[] toDerivedUnit(final double[] input, final double[] output)
throws ConversionException {
if (!(_unit instanceof DerivableUnit)) {
throw new ConversionException(this, getDerivedUnit());
}
final double origin = getOffset();
for (int i = input.length; --i >= 0;) {
output[i] = input[i] + origin;
}
return ((DerivableUnit) getUnit()).toDerivedUnit(output, output);
}
/**
* Converts a value in the convertible derived unit to the equivalent value
* in this unit.
*
* @param amount
* The value in the convertible derived unit.
* @return The equivalent value in this unit.
* @throws ConversionException
* Can't convert between units.
*/
public float fromDerivedUnit(final float amount) throws ConversionException {
return (float) fromDerivedUnit((double) amount);
}
/**
* Converts a value in the convertible derived unit to the equivalent value
* in this unit.
*
* @param amount
* The value in the convertible derived unit.
* @return The equivalent value in this unit.
* @throws ConversionException
* Can't convert between units.
*/
public double fromDerivedUnit(final double amount)
throws ConversionException {
if (!(_unit instanceof DerivableUnit)) {
throw new ConversionException(getDerivedUnit(), this);
}
return ((DerivableUnit) getUnit()).fromDerivedUnit(amount)
- getOffset();
}
/**
* Converts values in the convertible derived unit to the equivalent values
* in this unit.
*
* @param input
* The values in the convertible derived unit.
* @param output
* The equivalent values in this unit. May be the same array as
* input.
* @return output.
* @throws ConversionException
* Can't convert between units.
*/
public float[] fromDerivedUnit(final float[] input, final float[] output)
throws ConversionException {
if (!(_unit instanceof DerivableUnit)) {
throw new ConversionException(getDerivedUnit(), this);
}
((DerivableUnit) getUnit()).fromDerivedUnit(input, output);
final float origin = (float) getOffset();
for (int i = input.length; --i >= 0;) {
output[i] -= origin;
}
return output;
}
/**
* Converts values in the convertible derived unit to the equivalent values
* in this unit.
*
* @param input
* The values in the convertible derived unit.
* @param output
* The equivalent values in this unit. May be the same array as
* input.
* @return output.
* @throws ConversionException
* Can't convert between units.
*/
public double[] fromDerivedUnit(final double[] input, final double[] output)
throws ConversionException {
if (!(_unit instanceof DerivableUnit)) {
throw new ConversionException(getDerivedUnit(), this);
}
((DerivableUnit) getUnit()).fromDerivedUnit(input, output);
final double origin = getOffset();
for (int i = input.length; --i >= 0;) {
output[i] -= origin;
}
return output;
}
/**
* Indicates if this unit is semantically identical to an object.
*
* @param object
* The object.
* @return true if and only if this unit is semantically
* identical to object
* .
*/
@Override
public boolean equals(final Object object) {
if (this == object) {
return true;
}
if (_offset == 0) {
return object.equals(_unit);
}
if (!(object instanceof OffsetUnit)) {
return false;
}
final OffsetUnit that = (OffsetUnit) object;
return _offset == that._offset && _unit.equals(that._unit);
}
/**
* Returns the hash code of this instance.
*
* @return The hash code of this instance.
*/
@Override
public int hashCode() {
return (getOffset() == 0
? 0
: Double.valueOf(getOffset()).hashCode())
^ getUnit().hashCode();
}
/**
* Indicates if this unit is dimensionless.
*
* @return true if and only if this unit is dimensionless.
*/
public boolean isDimensionless() {
return getUnit().isDimensionless();
}
/**
* Returns the string representation of this unit.
*
* @return The string representation of this unit.
*/
@Override
public String toString() {
final String string = super.toString(); // get symbol or name
return string != null
? string
: getCanonicalString();
}
/**
* Returns the canonical string representation of the unit.
*
* @return The canonical string representation.
*/
public String getCanonicalString() {
return "(" + getUnit().toString() + ") @ " + getOffset();
}
/**
* Tests this class.
*/
public static void main(final String[] args) throws Exception {
final BaseUnit kelvin = BaseUnit.getOrCreate(UnitName.newUnitName(
"kelvin", null, "K"), BaseQuantity.THERMODYNAMIC_TEMPERATURE);
final OffsetUnit celsius = new OffsetUnit(kelvin, 273.15);
System.out.println("celsius.equals(kelvin)=" + celsius.equals(kelvin));
System.out.println("celsius.getUnit().equals(kelvin)="
+ celsius.getUnit().equals(kelvin));
final Unit celsiusKelvin = celsius.multiplyBy(kelvin);
System.out.println("celsiusKelvin.divideBy(celsius)="
+ celsiusKelvin.divideBy(celsius));
System.out.println("celsius.divideBy(kelvin)="
+ celsius.divideBy(kelvin));
System.out.println("kelvin.divideBy(celsius)="
+ kelvin.divideBy(celsius));
System.out.println("celsius.raiseTo(2)=" + celsius.raiseTo(2));
System.out.println("celsius.toDerivedUnit(1.)="
+ celsius.toDerivedUnit(1.));
System.out
.println("celsius.toDerivedUnit(new float[]{1,2,3}, new float[3])[1]="
+ celsius.toDerivedUnit(new float[] { 1, 2, 3 },
new float[3])[1]);
System.out.println("celsius.fromDerivedUnit(274.15)="
+ celsius.fromDerivedUnit(274.15));
System.out
.println("celsius.fromDerivedUnit(new float[]{274.15f},new float[1])[0]="
+ celsius.fromDerivedUnit(new float[] { 274.15f },
new float[1])[0]);
System.out
.println("celsius.equals(celsius)=" + celsius.equals(celsius));
final OffsetUnit celsius100 = new OffsetUnit(celsius, 100.);
System.out.println("celsius.equals(celsius100)="
+ celsius.equals(celsius100));
System.out.println("celsius.isDimensionless()="
+ celsius.isDimensionless());
final BaseUnit radian = BaseUnit.getOrCreate(UnitName.newUnitName(
"radian", null, "rad"), BaseQuantity.PLANE_ANGLE);
final OffsetUnit offRadian = new OffsetUnit(radian, 3.14159 / 2);
System.out.println("offRadian.isDimensionless()="
+ offRadian.isDimensionless());
;
}
}