javax.measure
Interface Measurable<Q extends Quantity>

All Superinterfaces:

java.lang.Comparable<Measurable<Q>>

All Known Implementing Classes:

Altitude, Amount, DecimalMeasure, Height, Measure, Time, VectorMeasure

public interface Measurable<Q extends Quantity>
extends java.lang.Comparable<Measurable<Q>>

This interface represents the measurable, countable, or comparable property or aspect of a thing.

Implementing instances are typically the result of a measurement:

         Measurable<Mass> weight = Measure.valueOf(180.0, POUND);
     

They can also be created from custom classes:

     class Delay implements Measurable<Duration> {
          private long nanoSeconds; // Implicit internal unit.
          public double doubleValue(Unit<Velocity> unit) { ... }
          public long longValue(Unit<Velocity> unit) { ... }
     }
     Thread.wait(new Delay(24, HOUR)); // Assuming Thread.wait(Measurable<Duration>) method.
     

Although measurable instances are for the most part scalar quantities; more complex implementations (e.g. vectors, data set) are allowed as long as an aggregate magnitude can be determined. For example:

     class Velocity3D implements Measurable<Velocity> {
          private double x, y, z; // Meter per seconds.
          public double doubleValue(Unit<Velocity> unit) { ... } // Returns vector norm.
          ... 
     }
     class Sensors<Q extends Quantity> extends Measure<double[], Q> {
          public doubleValue(Unit<Q> unit) { ... } // Returns median value. 
          ...
     } 

Version:

4.1, June 8, 2007

Author:

Jean-Marie Dautelle

Method Summary

double	doubleValue(Unit<Q> unit) Returns the value of this measurable stated in the specified unit as a double.
long	longValue(Unit<Q> unit) Returns the estimated integral value of this measurable stated in the specified unit as a long.

Methods inherited from interface java.lang.Comparable

compareTo

Method Detail

doubleValue

double doubleValue(Unit<Q> unit)

Returns the value of this measurable stated in the specified unit as a double. If the measurable has too great a magnitude to be represented as a double, it will be converted to Double.NEGATIVE_INFINITY or Double.POSITIVE_INFINITY as appropriate.

Parameters:

unit - the unit in which this measurable value is stated.

Returns:

the numeric value after conversion to type double.

longValue

long longValue(Unit<Q> unit)
               throws java.lang.ArithmeticException

Returns the estimated integral value of this measurable stated in the specified unit as a long.

Note: This method differs from the Number.longValue() in the sense that the closest integer value is returned and an ArithmeticException is raised instead of a bit truncation in case of overflow (safety critical).

Parameters:

unit - the unit in which the measurable value is stated.

Returns:

the numeric value after conversion to type long.

Throws:

java.lang.ArithmeticException - if this quantity cannot be represented as a long number in the specified unit.