org.das2.datum.Datum

A Datum is a number in the context of a Unit, for example "15 microseconds." A Datum object has methods for

Also a Datum's precision can be limited to improve formatting.

abs

abs( ) → Datum

return the absolute value (magnitude) of this Datum. If this datum is fill then the result is fill. This will have the same units as the datum.

Returns:

a Datum

See Also:

value() which returns the double value.


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add

add( Datum datum ) → Datum

returns a Datum whose value is the sum of this and datum, in this.getUnits().

Parameters

datum - Datum to add, that is convertible to this.getUnits().

Returns:

a Datum that is the sum of the two values in this Datum's units.

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add( Number value, Units units ) → Datum
add( double d, Units units ) → Datum

compareTo

compareTo( Object a ) → int

compare the datum to the object.

Parameters

a - the Object to compare this datum to.

Returns:

an int < 0 if this comes before Datum a in this Datum's units space, 0 if they are equal, and > 0 otherwise.

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compareTo( Datum a ) → int

convertTo

convertTo( Units units ) → Datum

creates an equivalent datum using a different unit. For example, x= Datum.create( 5, Units.seconds ); System.err.println( x.convertTo( Units.seconds ) );

Parameters

units - the new Datum's units

Returns:

a datum with the new units, that is equal to the original datum.

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create

create( double value ) → Datum

convenient method for creating a dimensionless Datum with the given value.

Parameters

value - the magnitude of the datum.

Returns:

a dimensionless Datum with the given value.

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create( double value, Units units ) → Datum
create( double value, Units units, org.das2.datum.format.DatumFormatter formatter ) → Datum
create( double value, Units units, double resolution ) → Datum
create( double value, Units units, double resolution, org.das2.datum.format.DatumFormatter formatter ) → Datum
create( long value ) → Datum
create( long value, Units units ) → Datum
create( long value, Units units, org.das2.datum.format.DatumFormatter formatter ) → Datum
create( int value ) → Datum
create( int value, Units units ) → Datum

div

div( Datum datum ) → Datum

Groovy scripting language uses this for overloading.

Parameters

datum - Datum to divide, that is convertible to this.getUnits().

Returns:

a Datum that is the divide of the two values in this Datum's units.

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divide

divide( Datum a ) → Datum

divide this by the datum a. Currently, only division is only supported:

   between convertable units, resulting in a Units.dimensionless quantity, or
   by a Units.dimensionless quantity, and a datum with this datum's units is returned.
This may change, as a generic SI units class is planned.

Parameters

a - the datum divisor.

Returns:

the quotient.

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divide( Number a, Units units ) → Datum
divide( double d ) → Datum

doubleValue

doubleValue( Units units ) → double

returns a double representing the datum in the context of units.

Parameters

units - the Units in which the double should be returned

Returns:

a double in the context of the provided units.

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equals

equals( Object a ) → boolean

returns true if the two datums are equal. That is, their double values are equal when converted to the same units.

Parameters

a - the Object to compare to.

Returns:

true if the datums are equal.

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equals( Datum a ) → boolean

exp10

exp10( ) → Datum

return Math.pow(10,v)

Returns:

Math.pow(10,v)

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ge

ge( Datum a ) → boolean

returns true if this is greater than or equal to a.

Parameters

a - a datum convertible to this Datum's units.

Returns:

true if this is greater than or equal to {@code a}.

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getFormatter

getFormatter( ) → DatumFormatter

returns a formatter suitable for formatting this datum as a string.

Returns:

a formatter to be used to format this Datum into a String.

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getResolution

getResolution( Units units ) → double

returns the resolution (or precision) of the datum. This is metadata for the datum, used primarily to limit the number of decimal places displayed in a string representation, but operators like add and multiply will propagate errors through the calculation.

Parameters

units - the Units in which the double resolution should be returned. Note the units must be convertible to this.getUnits().getOffsetUnits().

Returns:

the double resolution of the datum in the context of units.

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getUnits

getUnits( ) → Units

returns the datum's units. For example, UT times might have the units Units.us2000.

Returns:

the datum's units.

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gt

gt( Datum a ) → boolean

returns true if this is greater than a.

Parameters

a - a datum convertible to this Datum's units.

Returns:

true if this is greater than {@code a}.

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hashCode

hashCode( ) → int

returns a hashcode that is a function of the value and the units.

Returns:

a hashcode for the datum

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intValue

intValue( Units units ) → int

returns a int representing the datum in the context of units.

Parameters

units - the Units in which the int should be returned

Returns:

a double in the context of the provided units.

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isFill

isFill( ) → boolean

convenience method for checking to see if a datum is a fill datum.

Returns:

true if the value is fill as defined by the Datum's units.

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isFinite

isFinite( ) → boolean

returns true if the value is finite, that is not INFINITY or NaN.

Returns:

true if the value is finite, that is not INFINITY or NaN.

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le

le( Datum a ) → boolean

returns true if this is less than or equal to a.

Parameters

a - a datum convertible to this Datum's units.

Returns:

true if this is less than or equal to {@code a}.

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log10

log10( ) → Datum

return log10 of this datum.

Returns:

log10 of this datum.

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lt

lt( Datum a ) → boolean

returns true if this is less than a.

Parameters

a - a datum convertible to this Datum's units.

Returns:

true if this is less than {@code a}.

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minus

minus( Datum datum ) → Datum

Groovy scripting language uses this for overloading.

Parameters

datum - Datum to subtract, that is convertible to this.getUnits().

Returns:

a Datum that is the sum of the two values in this Datum's units.

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multiply

multiply( Datum a ) → Datum

multiply this by the datum a. Currently, only multiplication is only supported by a dimensionless datum, or when this is dimensionless. This may change, as a generic SI units class is planned. This should also throw an IllegalArgumentException if the units are LocationUnits (e.g. UT time), but doesn't. This may change.

Parameters

a - the datum to multiply

Returns:

the product.

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multiply( Number a, Units units ) → Datum
multiply( double d ) → Datum

negative

negative( ) → Datum

Groovy scripting language uses this negation operator.

Returns:

a Datum such that it plus this is 0.

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plus

plus( Datum datum ) → Datum

Groovy scripting language uses this for overloading.

Parameters

datum - Datum to add, that is convertible to this.getUnits().

Returns:

a Datum that is the sum of the two values in this Datum's units.

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positive

positive( ) → Datum

Groovy scripting language uses this positive operator.

Returns:

this datum.

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power

power( double b ) → Datum

Groovy scripting language uses this for overloading a**b.

Parameters

b - double to exponentiate, that is dimensionless.

Returns:

a Datum that is the exponentiate of the two values in this Datum's units.

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power( Datum datum ) → Datum

subtract

subtract( Datum datum ) → Datum

returns a Datum whose value is the difference of this and value. The returned Datum will have units according to the type of units subtracted. For example, "1979-01-02T00:00" - "1979-01-01T00:00" = "24 hours" (this datum's unit's offset units), while "1979-01-02T00:00" - "1 hour" = "1979-01-01T23:00" (this datum's units.) Note also the resolution of the result is calculated.

Parameters

datum - Datum to add, that is convertible to this.getUnits() or offset units.

Returns:

a Datum that is the sum of the two values in this Datum's units.

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subtract( Number a, Units units ) → Datum
subtract( double d, Units units ) → Datum

toString

toString( ) → String

returns a human readable String representation of the Datum, which should also be parseable with Units.parse()

Returns:

a human readable String representation of the Datum, which should also be parseable with Units.parse()

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value

value( ) → double

returns the double value without the unit, as long as the Units indicate this is a ratio measurement, and there is a meaningful 0. For example "5 Kg" → 5, but "2012-02-16T00:00" would throw an IllegalArgumentException. Note this was introduced because often we just need to check to see if a value is zero.

Returns:

a double

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