visad
Class BaseUnit

java.lang.Object
  visad.Unit
      visad.BaseUnit

All Implemented Interfaces:

Serializable

public final class BaseUnit
extends Unit
implements Serializable

A class that represents the base units of a system of units. Instances are immutable.

Author:

Steven R. Emmerson This is part of Steve Emerson's Unit package that has been incorporated into VisAD.

See Also:

Serialized Form

Field Summary

Fields inherited from class visad.Unit

hashCode

Method Summary

static BaseUnit	addBaseUnit(String quantityName, String unitName) Create a new base unit from the name of a quantity and the name of a unit.
static BaseUnit	addBaseUnit(String quantityName, String unitName, String abbreviation) Create a new base unit from from the name of a quantity, the name of a unit, and the unit's abbreviation.
static BaseUnit	addBaseUnit(String quantityName, String unitName, String abbreviation, boolean isDimless) Create a new base unit from from the name of a quantity, the name of a unit, the unit's abbreviation, and whether or not the unit is dimensionless.
Unit	divide(Unit that) Divide this unit by another unit.
protected Unit	divideInto(Unit that) Divide this unit into another unit.
boolean	equals(Unit unit) Indicates whether or not this instance equals a unit.
String	getDefinition() Returns 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(String[] args) Test this class.
Unit	multiply(Unit that) Multiply this unit by another unit.
Unit	pow(double power) Raise a unit to a power.
Unit	pow(int power) Raise a base unit to a power.
protected Unit	protectedClone(String identifier) Clones this unit, changing the identifier.
String	quantityName() Return the name of the quantity associated with this unit.
static BaseUnit	quantityNameToUnit(String quantityName) Find the base unit for the given quantity.
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.
String	unitName() Return the name of this unit.
static BaseUnit	unitNameToUnit(String unitName) Find the base unit with the given name.
String	unitSymbol() Return the symbol of this unit.

Methods inherited from class visad.Unit

adjustCheckAndCache, 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

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

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 base units include radian, degree, and steradian.

Specified by:

isDimensionless in class Unit

Returns:

True if an only if this unit is dimensionless.

scale

public Unit scale(double amount)
           throws UnitException

Description copied from class: Unit

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 to this instance scaled by the given amount.

Throws:

UnitException - This unit cannot be scaled.

shift

public Unit shift(double offset)
           throws UnitException

Description copied from class: Unit

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 instance with the origin shifted by the given amount.

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 base 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.

Promise:

This unit has not been modified.

pow

public Unit pow(double power)
         throws IllegalArgumentException

Raise a unit to a power.

Specified by:

pow in class Unit

Parameters:

power - The power to raise this unit by. The value must be integral or reciprocal integral.

Returns:

The unit resulting from raising this unit to power.

Throws:

IllegalArgumentException - power has a non-integral or non-reciprocal integral value.

Promise:

The unit has not been modified.

root

public Unit root(int root)
          throws 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:

IllegalArgumentException - The root value is zero or the resulting unit would have a non-integral unit dimension.

Promise:

This unit has not been modified.

unitName

public String unitName()

Return the name of this unit.

Returns:

The name of this unit (e.g. "meter").

unitSymbol

public String unitSymbol()

Return the symbol of this unit. This is the same as the identifier.

Returns:

The symbol of this unit (e.g. "m").

quantityName

public String quantityName()

Return the name of the quantity associated with this unit.

Returns:

The name this units quantity (e.g. "Length").

addBaseUnit

public static BaseUnit addBaseUnit(String quantityName,
                                   String unitName)
                            throws UnitException

Create a new base unit from the name of a quantity and the name of a unit. The unit abbreviation will be the same as the unit name. The unit will not be dimensionless.

Parameters:

quantityName - The name of the associated quantity (e.g. "Length").

unitName - The name for the unit (e.g. "meter").

Returns:

A new base unit or the previously created one with the same names.

Throws:

UnitException - Name, abbreviation, or quantity name is null or attempt to redefine the base unit associated with quantityName.

Promise:

The new quantity and unit has been added to the database.

Requirements:

The arguments are non-null. The quantity name has not been used before or the unit name is the same as before.

addBaseUnit

public static BaseUnit addBaseUnit(String quantityName,
                                   String unitName,
                                   String abbreviation)
                            throws UnitException

Create a new base unit from from the name of a quantity, the name of a unit, and the unit's abbreviation. The unit will not be dimensionless.

Parameters:

quantityName - The name of the associated quantity (e.g. "Length").

unitName - The name for the unit (e.g. "meter").

abbreviation - The abbreviation for the unit (e.g. "m").

Returns:

A new base unit or the previously created one with the same names.

Throws:

UnitException - Name, abbreviation, or quantity name is null or attempt to redefine the base unit associated with quantityName.

Promise:

The new quantity and unit has been added to the database.

Requirements:

The arguments are non-null. The quantity name has not been used before or the unit name is the same as before.

addBaseUnit

public static BaseUnit addBaseUnit(String quantityName,
                                   String unitName,
                                   String abbreviation,
                                   boolean isDimless)
                            throws UnitException

Create a new base unit from from the name of a quantity, the name of a unit, the unit's abbreviation, and whether or not the unit is dimensionless.

Parameters:

quantityName - The name of the associated quantity (e.g. "Length").

unitName - The name for the unit (e.g. "meter").

abbreviation - The abbreviation for the unit (e.g. "m").

isDimless - Whether or not the unit is dimensionless.

Returns:

A new base unit or the previously created one with the same names.

Throws:

UnitException - Name, abbreviation, or quantity name is null or attempt to redefine the base unit associated with quantityName.

Promise:

The new quantity and unit has been added to the database.

Requirements:

The arguments are non-null. The quantity name has not been used before or the unit name is the same as before.

unitNameToUnit

public static BaseUnit unitNameToUnit(String unitName)

Find the base unit with the given name.

Parameters:

unitName - The name of the unit (e.g. "meter").

Returns:

The existing base unit with the given name or null if no such units exists.

Requirements:

The argument is non-null.

quantityNameToUnit

public static BaseUnit quantityNameToUnit(String quantityName)

Find the base unit for the given quantity.

Parameters:

quantityName - The name of the quantity (e.g. "Length").

Returns:

The existing base unit for the given quantity or null if no such unit exists.

Requirements:

The argument is non-null.

main

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

Test this class.

Parameters:

args - Arguments (ignored).

Throws:

UnitException - A problem occurred.

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.

Promise:

Neither unit has been modified.

Requirements:

The units are 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.

Promise:

Neither unit has been modified.

Requirements:

The units are 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.

Promise:

Neither unit has been modified.

Requirements:

The units are identical.

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.

Promise:

Neither unit has been modified.

Requirements:

The units are identical.

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.

Promise:

Neither unit has been modified.

Requirements:

The units are identical.

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.

Promise:

Neither unit has been modified.

Requirements:

The units are identical.

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.

Promise:

Neither unit has been modified.

Requirements:

The units are identical.

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.

Promise:

Neither unit has been modified.

Requirements:

The units are identical.

getDefinition

public String getDefinition()

Returns the definition of this unit. The definition of a BaseUnit is the same as the BaseUnit's identifier.

Specified by:

getDefinition in class Unit

Returns:

The definition of this unit. Won't be null but may be empty.

protectedClone

protected Unit protectedClone(String identifier)
                       throws UnitException

Clones this unit, changing the identifier. This method always throws an exception because base units may not be cloned.

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 this this instance but with the given identifier.

Throws:

UnitException - Base units may not be cloned. Always thrown.

equals

public boolean equals(Unit unit)

Indicates whether or not this instance equals a unit.

Specified by:

equals in class Unit

Parameters:

unit - A unit.

Returns:

true if and only if this instance is equal to 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).

multiply

public Unit multiply(Unit that)
              throws UnitException

Multiply this 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.

Promise:

Neither unit has been modified.

divide

public Unit divide(Unit that)
            throws UnitException

Divide this 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.

Promise:

Neither unit has been modified.

divideInto

protected Unit divideInto(Unit that)
                   throws UnitException

Divide this unit into another unit.

Specified by:

divideInto in class Unit

Parameters:

that - The unit to divided this unit.

Returns:

The quotient of the two units.

Throws:

UnitException - Meaningless operation.

Promise:

Neither unit has been modified.

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.

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.