visad

Class DerivedUnit

java.lang.Object

visad.Unit

visad.DerivedUnit

All Implemented Interfaces:

java.io.Serializable

public final class DerivedUnit
extends Unit
implements java.io.Serializable

A class that represents a unit consisting of zero or more base units. Instances are immutable.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
DerivedUnit() Construct a dimensionless derived unit.
DerivedUnit(BaseUnit baseUnit) Construct a derived unit from a base unit.
DerivedUnit(BaseUnit[] baseUnits, int[] powers) Construct a derived unit from an array base units and powers.
DerivedUnit(BaseUnit[] baseUnits, int[] powers, java.lang.String identifier) Construct a derived unit from an array base units, powers, and an identifier.
DerivedUnit(DerivedUnit that, java.lang.String identifier) Construct a derived unit from a derived unit and an identifier.
DerivedUnit(java.lang.String identifier) Construct a dimensionless derived unit with an identifier.

Method Summary

Modifier and Type	Method and Description
Unit	divide(Unit that) Divide a derived unit by another unit.
boolean	equals(Unit unit) Indicates if this instance equals a unit.
java.lang.String	getDefinition() Return the definition of this unit.
DerivedUnit	getDerivedUnit() Returns the derived unit that underlies this unit.
int	hashCode() Returns the hash code of this instance.
boolean	isConvertible(Unit unit) Indicate whether this unit is convertible with another unit.
boolean	isDimensionless() Indicates if this instance is dimensionless.
Unit	log(double base) Returns the logarithmic unit that has this unit as its reference level.
static void	main(java.lang.String[] args) Test this class.
Unit	multiply(DerivedUnit that) Multiply a derived unit by a derived unit.
Unit	multiply(Unit that) Multiply a derived unit by another unit.
Unit	pow(double power) Raise a derived unit to a power.
Unit	pow(int power) Raise a derived unit to a power.
Unit	root(int root) Returns the N-th root of this unit.
Unit	scale(double amount) Scale this unit by an amount.
Unit	shift(double offset) Shift this unit by an amount.
double[]	toThat(double[] values, Unit that) Convert values from this unit to another unit.
double[]	toThat(double[] values, Unit that, boolean copy) Convert values from this unit to another unit.
float[]	toThat(float[] values, Unit that) Convert values from this unit to another unit.
float[]	toThat(float[] values, Unit that, boolean copy) Convert values from this unit to another unit.
double[]	toThis(double[] values, Unit that) Convert values to this unit from another unit.
double[]	toThis(double[] values, Unit that, boolean copy) Convert values to this unit from another unit.
float[]	toThis(float[] values, Unit that) Convert values to this unit from another unit.
float[]	toThis(float[] values, Unit that, boolean copy) Convert values to this unit from another unit.

Methods inherited from class visad.Unit

canConvert, canConvertArray, clone, convertTuple, convertTuple, convertTuple, convertTuple, copyUnitsArray, equals, getAbsoluteUnit, getIdentifier, sqrt, toString, toThat, toThis, transformUnits, transformUnits, transformUnits, transformUnits

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

DerivedUnit

public DerivedUnit()

Construct a dimensionless derived unit. The identifier of the unit will be empty.

DerivedUnit

public DerivedUnit(java.lang.String identifier)

Construct a dimensionless derived unit with an identifier.

Parameters:

identifier - Name or abbreviation for the unit. May be null or empty.

DerivedUnit

public DerivedUnit(BaseUnit baseUnit)

Construct a derived unit from a base unit. The identifier of the unit will be that of the base unit.

Parameters:

baseUnit - The base unit.

DerivedUnit

public DerivedUnit(BaseUnit[] baseUnits,
                   int[] powers)

Construct a derived unit from an array base units and powers. The identifier of the unit with be that of the base unit if there's only one base unit; otherwise, the identifier will be null.

Parameters:

baseUnits - The array of base units (e.g. {m, s}).

powers - The array of powers (e.g. {1, -1} to create a m/s unit).

DerivedUnit

public DerivedUnit(BaseUnit[] baseUnits,
                   int[] powers,
                   java.lang.String identifier)

Construct a derived unit from an array base units, powers, and an identifier.

Parameters:

baseUnits - The array of base units (e.g. {m, s}).

powers - The array of powers (e.g. {1, -1} to create a m/s unit).

identifier - Name or abbreviation for the unit. May be null or empty.

DerivedUnit

public DerivedUnit(DerivedUnit that,
                   java.lang.String identifier)

Construct a derived unit from a derived unit and an identifier.

Parameters:

that - The derived unit.

identifier - Name or abbreviation for the unit. May be null or empty.

Method Detail

isDimensionless

public boolean isDimensionless()

Indicates if this instance is dimensionless. A unit is dimensionless if it is a measure of a dimensionless quantity like angle or concentration. Examples of dimensionless units include radian, degree, steradian, and "g/kg".

Specified by:

isDimensionless in class Unit

Returns:

True if an only if this unit is dimensionless.

scale

public Unit scale(double amount)
           throws UnitException

Scale this unit by an amount.

Specified by:

scale in class Unit

Parameters:

amount - The amount by which to scale this unit. E.g. Unit yard = meter.scale(0.9144);

Returns:

A unit equal this this unit scaled by the given amount.

Throws:

UnitException - This unit cannot be scaled.

shift

public Unit shift(double offset)
           throws UnitException

Shift this unit by an amount.

Specified by:

shift in class Unit

Parameters:

offset - The amount by which to shift this unit. E.g. Unit celsius = kelvin.shift(273.15);

Returns:

A unit equal to this unit with the origin shifted to the given point.

Throws:

UnitException - The unit subclass is unknown.

log

public Unit log(double base)

Description copied from class: Unit

Returns the logarithmic unit that has this unit as its reference level. Not all units can be used as a reference level.

Specified by:

log in class Unit

Parameters:

base - The logarithmic base: one of 2, Math.E, or 10.

Returns:

The logarithmic unit that has this instance as its reference level.

pow

public Unit pow(int power)

Raise a derived unit to a power.

Specified by:

pow in class Unit

Parameters:

power - The power to raise this unit by.

Returns:

The unit resulting from raising this unit to power.

root

public Unit root(int root)
          throws java.lang.IllegalArgumentException

Returns the N-th root of this unit.

Specified by:

root in class Unit

Parameters:

root - The root to take (e.g. 2 means square root). May not be zero.

Returns:

The unit corresponding to the root-th root of this unit.

Throws:

java.lang.IllegalArgumentException - root is zero or the result would have a non-integral unit dimension.

pow

public Unit pow(double power)
         throws java.lang.IllegalArgumentException

Raise a derived unit to a power.

Specified by:

pow in class Unit

Parameters:

power - The power to raise this unit by. If this unit is not dimensionless, then the value must be an integer or the reciprocal of an integer.

Returns:

The unit resulting from raising this unit to power.

Throws:

java.lang.IllegalArgumentException - This unit is not dimensionless and power is neither an integer nor the reciprocal of an integer.

getDefinition

public java.lang.String getDefinition()

Return the definition of this unit.

Specified by:

getDefinition in class Unit

Returns:

The definition of this unit (e.g. "m.s-1").

main

public static void main(java.lang.String[] args)
                 throws UnitException

Test this class.

Parameters:

args - Arguments (ignored).

Throws:

UnitException - A problem occurred.

multiply

public Unit multiply(Unit that)
              throws UnitException

Multiply a derived unit by another unit.

Specified by:

multiply in class Unit

Parameters:

that - The unit with which to multiply this unit.

Returns:

The product of the two units.

Throws:

UnitException - Meaningless operation.

multiply

public Unit multiply(DerivedUnit that)

Multiply a derived unit by a derived unit.

Parameters:

that - The derived unit with which to multiply this unit.

Returns:

The product of the two units.

divide

public Unit divide(Unit that)
            throws UnitException

Divide a derived unit by another unit.

Specified by:

divide in class Unit

Parameters:

that - The unit to divide into this unit.

Returns:

The quotient of the two units.

Throws:

UnitException - Meaningless operation.

toThis

public double[] toThis(double[] values,
                       Unit that)
                throws UnitException

Convert values to this unit from another unit.

Specified by:

toThis in class Unit

Parameters:

values - The values to be converted.

that - The unit of values.

Returns:

The converted values in units of this unit.

Throws:

UnitException - The units are not convertible.

toThis

public float[] toThis(float[] values,
                      Unit that)
               throws UnitException

Convert values to this unit from another unit.

Specified by:

toThis in class Unit

Parameters:

values - The values to be converted.

that - The unit of values.

Returns:

The converted values in units of this unit.

Throws:

UnitException - The units are not convertible.

toThis

public double[] toThis(double[] values,
                       Unit that,
                       boolean copy)
                throws UnitException

Convert values to this unit from another unit.

Overrides:

toThis in class Unit

Parameters:

values - The values to be converted.

that - The unit of values.

copy - if false and that equals this, return values, else return a new array

Returns:

The converted values in units of this unit.

Throws:

UnitException - The units are not convertible.

toThis

public float[] toThis(float[] values,
                      Unit that,
                      boolean copy)
               throws UnitException

Convert values to this unit from another unit.

Overrides:

toThis in class Unit

Parameters:

values - The values to be converted.

that - The unit of values.

copy - if false and that equals this, return values, else return a new array

Returns:

The converted values in units of this unit.

Throws:

UnitException - The units are not convertible.

toThat

public double[] toThat(double[] values,
                       Unit that)
                throws UnitException

Convert values from this unit to another unit.

Specified by:

toThat in class Unit

Parameters:

values - The values to be converted in units of this unit.

that - The unit to which to convert the values.

Returns:

The converted values.

Throws:

UnitException - The units are not convertible.

toThat

public float[] toThat(float[] values,
                      Unit that)
               throws UnitException

Convert values from this unit to another unit.

Specified by:

toThat in class Unit

Parameters:

values - The values to be converted in units of this unit.

that - The unit to which to convert the values.

Returns:

The converted values.

Throws:

UnitException - The units are not convertible.

toThat

public double[] toThat(double[] values,
                       Unit that,
                       boolean copy)
                throws UnitException

Convert values from this unit to another unit.

Overrides:

toThat in class Unit

Parameters:

values - The values to be converted in units of this unit.

that - The unit to which to convert the values.

copy - if false and that equals this, return values, else return a new array

Returns:

The converted values.

Throws:

UnitException - The units are not convertible.

toThat

public float[] toThat(float[] values,
                      Unit that,
                      boolean copy)
               throws UnitException

Convert values from this unit to another unit.

Overrides:

toThat in class Unit

Parameters:

values - The values to be converted in units of this unit.

that - The unit to which to convert the values.

copy - if false and that equals this, return values, else return a new array

Returns:

The converted values.

Throws:

UnitException - The units are not convertible.

isConvertible

public boolean isConvertible(Unit unit)

Indicate whether this unit is convertible with another unit. If one unit is convertible with another, then the toThis(...)/ and toThat(...) methods will not throw a UnitException. Unit A is convertible with unit B if and only if unit B is convertible with unit A; hence, calling-order is irrelevant.

Specified by:

isConvertible in class Unit

Parameters:

unit - The other unit.

Returns:

True if and only if this unit is convertible with the other unit.

equals

public boolean equals(Unit unit)

Indicates if this instance equals a unit.

Specified by:

equals in class Unit

Parameters:

unit - The unit.

Returns:

true if and only if this instance equals the unit.

hashCode

public int hashCode()

Returns the hash code of this instance. Object.hashCode() should be overridden whenever Object.equals(Object) is.

Specified by:

hashCode in class Unit

Returns:

The hash code of this instance (includes the values).

getDerivedUnit

public DerivedUnit getDerivedUnit()

Description copied from class: Unit

Returns the derived unit that underlies this unit.

Specified by:

getDerivedUnit in class Unit

Returns:

The derived unit that underlies this unit.