public class Measurement extends Object implements Comparable
A Measurement
object is used for maintaining the tuple of value,
error, unit and timestamp. The value and error are represented as doubles
and the time is measured in milliseconds since midnight, January 1, 1970 UTC.
Mathematic methods are provided that correctly calculate taking the error
into account. A runtime error will occur when two measurements are used in an
incompatible way. E.g., when a speed (m/s) is added to a distance (m). The
measurement class will correctly track changes in unit during multiplication
and division, always coercing the result to the most simple form. See
Unit
for more information on the supported units.
Errors in the measurement class are absolute errors. Measurement errors should use the P95 rule. Actual values must fall in the range value +/ error 95% or more of the time.
A Measurement
object is immutable in order to be easily shared.
Note: This class has a natural ordering that is inconsistent with equals. See
compareTo(Object)
.
Constructor and Description 

Measurement(double value)
Create a new
Measurement object with an error of 0.0, a unit of
Unit.unity and a time of zero. 
Measurement(double value,
double error,
Unit unit)
Create a new
Measurement object with a time of zero. 
Measurement(double value,
double error,
Unit unit,
long time)
Create a new
Measurement object. 
Measurement(double value,
Unit unit)
Create a new
Measurement object with an error of 0.0 and a time
of zero. 
Modifier and Type  Method and Description 

Measurement 
add(double d)
Returns a new
Measurement object that is the sum of this object
added to the specified value. 
Measurement 
add(double d,
Unit u)
Returns a new
Measurement object that is the sum of this object
added to the specified value. 
Measurement 
add(Measurement m)
Returns a new
Measurement object that is the sum of this object
added to the specified object. 
int 
compareTo(Object obj)
Compares this object with the specified object for order.

Measurement 
div(double d)
Returns a new
Measurement object that is the quotient of this
object divided by the specified value. 
Measurement 
div(double d,
Unit u)
Returns a new
Measurement object that is the quotient of this
object divided by the specified value. 
Measurement 
div(Measurement m)
Returns a new
Measurement object that is the quotient of this
object divided by the specified object. 
boolean 
equals(Object obj)
Returns whether the specified object is equal to this object.

double 
getError()
Returns the error of this
Measurement object. 
long 
getTime()
Returns the time at which this
Measurement object was taken. 
Unit 
getUnit()
Returns the
Unit object of this Measurement object. 
double 
getValue()
Returns the value of this
Measurement object. 
int 
hashCode()
Returns a hash code value for this object.

Measurement 
mul(double d)
Returns a new
Measurement object that is the product of this
object multiplied by the specified value. 
Measurement 
mul(double d,
Unit u)
Returns a new
Measurement object that is the product of this
object multiplied by the specified value. 
Measurement 
mul(Measurement m)
Returns a new
Measurement object that is the product of this
object multiplied by the specified object. 
Measurement 
sub(double d)
Returns a new
Measurement object that is the subtraction of the
specified value from this object. 
Measurement 
sub(double d,
Unit u)
Returns a new
Measurement object that is the subtraction of the
specified value from this object. 
Measurement 
sub(Measurement m)
Returns a new
Measurement object that is the subtraction of the
specified object from this object. 
String 
toString()
Returns a
String object representing this Measurement
object. 
public Measurement(double value, double error, Unit unit, long time)
Measurement
object.value
 The value of the Measurement
.error
 The error of the Measurement
.unit
 The Unit
object in which the value is measured. If
this argument is null
, then the unit will be set to
Unit.unity
.time
 The time measured in milliseconds since midnight, January 1,
1970 UTC.public Measurement(double value, double error, Unit unit)
Measurement
object with a time of zero.value
 The value of the Measurement
.error
 The error of the Measurement
.unit
 The Unit
object in which the value is measured. If
this argument is null
, then the unit will be set to
Unit.unity
.public Measurement(double value, Unit unit)
Measurement
object with an error of 0.0 and a time
of zero.value
 The value of the Measurement
.unit
 The Unit
in which the value is measured. If this
argument is null
, then the unit will be set to
Unit.unity
.public Measurement(double value)
Measurement
object with an error of 0.0, a unit of
Unit.unity
and a time of zero.value
 The value of the Measurement
.public final double getValue()
Measurement
object.Measurement
object as a double.public final double getError()
Measurement
object. The error is always
a positive value.Measurement
as a double.public final Unit getUnit()
Unit
object of this Measurement
object.Unit
object of this Measurement
object.Unit
public final long getTime()
Measurement
object was taken. The
time is measured in milliseconds since midnight, January 1, 1970 UTC, or
zero when not defined.Measurement
object was taken or
zero.public Measurement mul(Measurement m)
Measurement
object that is the product of this
object multiplied by the specified object.m
 The Measurement
object that will be multiplied with this
object.Measurement
that is the product of this object
multiplied by the specified object. The error and unit of the new
object are computed. The time of the new object is set to the
time of this object.ArithmeticException
 If the Unit
objects of this object
and the specified object cannot be multiplied.Unit
public Measurement mul(double d, Unit u)
Measurement
object that is the product of this
object multiplied by the specified value.d
 The value that will be multiplied with this object.u
 The Unit
of the specified value.Measurement
object that is the product of this
object multiplied by the specified value. The error and unit of
the new object are computed. The time of the new object is set to
the time of this object.ArithmeticException
 If the units of this object and the specified
value cannot be multiplied.Unit
public Measurement mul(double d)
Measurement
object that is the product of this
object multiplied by the specified value.d
 The value that will be multiplied with this object.Measurement
object that is the product of this
object multiplied by the specified value. The error of the new
object is computed. The unit and time of the new object is set to
the unit and time of this object.public Measurement div(Measurement m)
Measurement
object that is the quotient of this
object divided by the specified object.m
 The Measurement
object that will be the divisor of this
object.Measurement
object that is the quotient of this
object divided by the specified object. The error and unit of the
new object are computed. The time of the new object is set to the
time of this object.ArithmeticException
 If the Unit
objects of this object
and the specified object cannot be divided.Unit
public Measurement div(double d, Unit u)
Measurement
object that is the quotient of this
object divided by the specified value.d
 The value that will be the divisor of this object.u
 The Unit
object of the specified value.Measurement
that is the quotient of this object
divided by the specified value. The error and unit of the new
object are computed. The time of the new object is set to the
time of this object.ArithmeticException
 If the Unit
objects of this object
and the specified object cannot be divided.Unit
public Measurement div(double d)
Measurement
object that is the quotient of this
object divided by the specified value.d
 The value that will be the divisor of this object.Measurement
object that is the quotient of this
object divided by the specified value. The error of the new
object is computed. The unit and time of the new object is set to
the Unit
and time of this object.public Measurement add(Measurement m)
Measurement
object that is the sum of this object
added to the specified object.
The error and unit of the new object are computed. The time of the new
object is set to the time of this object.m
 The Measurement
object that will be added with this
object.Measurement
object that is the sum of this and m.ArithmeticException
 If the Unit
objects of this object
and the specified object cannot be added.Unit
public Measurement add(double d, Unit u)
Measurement
object that is the sum of this object
added to the specified value.d
 The value that will be added with this object.u
 The Unit
object of the specified value.Measurement
object that is the sum of this object
added to the specified value. The unit of the new object is
computed. The error and time of the new object is set to the
error and time of this object.ArithmeticException
 If the Unit
objects of this object
and the specified value cannot be added.Unit
public Measurement add(double d)
Measurement
object that is the sum of this object
added to the specified value.d
 The value that will be added with this object.Measurement
object that is the sum of this object
added to the specified value. The error, unit, and time of the
new object is set to the error, Unit
and time of this
object.public Measurement sub(Measurement m)
Measurement
object that is the subtraction of the
specified object from this object.m
 The Measurement
object that will be subtracted from this
object.Measurement
object that is the subtraction of the
specified object from this object. The error and unit of the new
object are computed. The time of the new object is set to the
time of this object.ArithmeticException
 If the Unit
objects of this object
and the specified object cannot be subtracted.Unit
public Measurement sub(double d, Unit u)
Measurement
object that is the subtraction of the
specified value from this object.d
 The value that will be subtracted from this object.u
 The Unit
object of the specified value.Measurement
object that is the subtraction of the
specified value from this object. The unit of the new object is
computed. The error and time of the new object is set to the
error and time of this object.ArithmeticException
 If the Unit
objects of this object
and the specified object cannot be subtracted.Unit
public Measurement sub(double d)
Measurement
object that is the subtraction of the
specified value from this object.d
 The value that will be subtracted from this object.Measurement
object that is the subtraction of the
specified value from this object. The error, unit and time of the
new object is set to the error, Unit
object and time of
this object.public String toString()
String
object representing this Measurement
object.public int compareTo(Object obj)
Note: This class has a natural ordering that is inconsistent with equals.
For this method, another Measurement
object is considered equal
if there is some x
such that
getValue()  getError() <= x <= getValue() + getError()for both
Measurement
objects being compared.compareTo
in interface Comparable
obj
 The object to be compared.ClassCastException
 If the specified object is not of type
Measurement
.ArithmeticException
 If the unit of the specified
Measurement
object is not equal to the Unit
object of this object.public int hashCode()
public boolean equals(Object obj)
Measurement
objects are equal if they have same value, error and
Unit
.
Note: This class has a natural ordering that is inconsistent with equals.
See compareTo(Object)
.
Copyright © OSGi Alliance (2000, 2015). All Rights Reserved. Licensed under the OSGi Specification License, Version 2.0