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.

See Also:

Serialized Form

Constructor Summary

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

Unit	divide(Unit that) Divide a derived unit by another unit.
protected Unit	divideInto(Unit that) Divide a derived unit into another unit.
boolean	equals(Unit unit) Indicates if this instance equals a unit.
java.lang.String	getDefinition() Return the definition of this unit.
boolean	isConvertible(Unit unit) Indicate whether this unit is convertible with another unit.
boolean	isDimensionless() Indicates if this instance is dimensionless.
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.
protected static visad.Factor[]	newFactors(BaseUnit[] baseUnits, int[] powers) Creates an array of Factor-s from arrays of base units and powers.
Unit	pow(double power) Raise a derived unit to a power.
Unit	pow(int power) Raise a derived unit to a power.
protected Unit	protectedClone(java.lang.String identifier) Clones this unit, changing the identifier.
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.
float[]	toThat(float[] values, Unit that) Convert values from this unit to another unit.
double[]	toThis(double[] values, Unit that) Convert values to this unit from another unit.
float[]	toThis(float[] values, Unit that) Convert values to this unit from another unit.

Methods inherited from class visad.Unit

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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, 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

newFactors

protected static visad.Factor[] newFactors(BaseUnit[] baseUnits,
                                           int[] powers)

Creates an array of Factor-s from arrays of base units and powers.

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).

Returns:

An array of Factors equivalent to the given base units and powers.

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.

protectedClone

protected Unit protectedClone(java.lang.String identifier)

Clones this unit, changing the identifier.

Specified by:

protectedClone in class Unit

Parameters:

identifier - The name or abbreviation for the cloned unit. May be null or empty.

Returns:

A unit equal to this unit but with the given identifier.

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.

scale

public Unit scale(double amount)
           throws UnitException

Scale this unit by an amount.

Overrides:

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.

Overrides:

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.

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.

divideInto

protected Unit divideInto(Unit that)
                   throws UnitException

Divide a derived unit into another unit.

Specified by:

divideInto in class Unit

Parameters:

that - The unit to be divided by 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.

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.

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.