unit.java

OSGI这是一个中间件,与UPNP齐名,是用于移植到嵌入式平台之上

/*
 * $Header: /home/wistrand/cvs/knopflerfish.org/osgi/bundles/measurement/src/org/osgi/util/measurement/Unit.java,v 1.1.1.1 2004/03/05 20:35:14 wistrand Exp $
 *
 * Copyright (c) The Open Services Gateway Initiative (2002).
 * All Rights Reserved.
 *
 * Implementation of certain elements of the Open Services Gateway Initiative
 * (OSGI) Specification may be subject to third party intellectual property
 * rights, including without limitation, patent rights (such a third party may
 * or may not be a member of OSGi). OSGi is not responsible and shall not be
 * held responsible in any manner for identifying or failing to identify any or
 * all such third party intellectual property rights.
 *
 * This document and the information contained herein are provided on an "AS
 * IS" basis and OSGI DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL
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 * FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL OSGI BE LIABLE FOR ANY
 * LOSS OF PROFITS, LOSS OF BUSINESS, LOSS OF USE OF DATA, INTERRUPTION OF
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 * All Company, brand and product names may be trademarks that are the sole
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 */

package org.osgi.util.measurement;

import java.util.*;

/**
 * A unit system for measurements.
 *
 * This class contains definitions of the most common SI units.
 * <p>
 *
 * <p>This class only support exponents for the base SI units in the range -64 to +63.
 * Any operation which produces an exponent outside of this range will result in
 * a <tt>Unit</tt> object with undefined exponents.
 *
 * @version $Revision: 1.1.1.1 $
 * @author Open Services Gateway Initiative
 */

/*
 * This local class maintains the information about units.
 * It can calculate new units when two values are multiplied,
 * divided, added or subtracted.
 * <p>
 * The unit works with the 7 basic SI types + rad +
 * up to 2^6 custom types. For each type, the unit keeps
 * a bit mask with the exponents of the basic types. Eg. m/s is
 * m = 1, s = -1. Multiplying one unit with another means
 * that the bit masks are added, dividing means that the bit masks
 * are subtracted.
 * <p>
 * This class can handle any reasonable combination of SI
 * units. However, it will always try to coerce results back
 * into the basic set. E.g. when you do V*A you should get
 * W and not m2.kg/s3 . Only when the existing types do not
 * match does the unit fallback to the expanded form.
 * <p>
 * This class uses offset arithmetic.
 * This means that the exponents are stored in an long.
 * The special field is used for units that should not
 * be arithmetically divided or multiplied, like longitude
 * and lattitude. These special units can however, be divided and multiplied
 * by the basic 7 constants of the SI, e.g. deg/s.
 */

public class Unit
{
	private final static long UNITY =   		createType(0,0,0,0,0,0,0,0,0);
	private final static long ZERO =			0x40L;
	private final static long MASK =			0x7fL;
	private final static int m_SHIFT =  		 0;
	private final static int s_SHIFT =  		 7;
	private final static int kg_SHIFT = 		14;
	private final static int K_SHIFT =  		21;
	private final static int A_SHIFT =  		28;
	private final static int mol_SHIFT =		35;
	private final static int cd_SHIFT = 		42;
	private final static int rad_SHIFT = 		49;
	private final static int x_SHIFT =  		56;
	private final static long m_MASK =  		MASK << m_SHIFT;
	private final static long s_MASK =  		MASK << s_SHIFT;
	private final static long kg_MASK = 		MASK << kg_SHIFT;
	private final static long K_MASK =  		MASK << K_SHIFT;
	private final static long A_MASK =  		MASK << A_SHIFT;
	private final static long mol_MASK =		MASK << mol_SHIFT;
	private final static long cd_MASK = 		MASK << cd_SHIFT;
	private final static long rad_MASK = 		MASK << rad_SHIFT;
	private final static long x_MASK =  		MASK << x_SHIFT;

	/** No Unit (Unity) */
	public final static Unit  unity	= new Unit( "", UNITY);   // Unity

	/* SI Base Units */
	/** The length unit meter (m) */
	public final static Unit  m 	   = new Unit("m",   createType(0,0,0,0,0,0,0,0,1)); // Distance meter

	/** The time unit second (s) */
	public final static Unit  s 	   = new Unit("s",   createType(0,0,0,0,0,0,0,1,0));   // Time				Seconds	s

	/** The mass unit kilogram (kg) */
	public final static Unit  kg	   = new Unit("kg",  createType(0,0,0,0,0,0,1,0,0));   // Mass				kilogram kg

	/** The temperature unit kelvin (K) */
	public final static Unit  K 	   = new Unit("K",   createType(0,0,0,0,0,1,0,0,0));   // Temperature		kelvin	K

	/** The electric current unit ampere (A) */
	public final static Unit  A 	   = new Unit("A",   createType(0,0,0,0,1,0,0,0,0));   // Current			ampere	A

	/** The amount of substance unit mole (mol) */
	public final static Unit  mol  	= new Unit("mol", createType(0,0,0,1,0,0,0,0,0));   // Substance		mole	mol

	/** The luminous intensity unit candela (cd) */
	public final static Unit  cd	   = new Unit("cd",  createType(0,0,1,0,0,0,0,0,0));   // Light			candela	cd



	/* SI Derived Units */
	/** The speed unit meter per second (m/s) */
	public final static Unit  m_s  	= new Unit("m/s", createType(0,0,0,0,0,0,0,-1,1));   // Speed 					m/s

	/** The acceleration unit meter per second squared (m/s<sup>2</sup>) */
	public final static Unit  m_s2 	= new Unit("m/s2",createType(0,0,0,0,0,0,0,-2,1));   // Acceleration				m/s^2

	/** The area unit square meter(m<sup>2</sup>) */
	public final static Unit  m2	   = new Unit("m2",  createType(0,0,0,0,0,0,0,0,2));   // Surface					m^2

	/** The volume unit cubic meter (m<sup>3</sup>) */
	public final static Unit  m3	   = new Unit("m3",  createType(0,0,0,0,0,0,0,0,3));   // Volume					m^3

	/** The frequency unit hertz (Hz).
		  <p>hertz is expressed in SI units as 1/s */
	public final static Unit  Hz	   = new Unit("Hz",  createType(0,0,0,0,0,0,0,-1,0));   // Frequency				1/s

	/** The force unit newton (N).
		<p>N is expressed in SI units as m&#183;kg/s<sup>2</sup> */
	public final static Unit  N 	   = new Unit("N",   createType(0,0,0,0,0,0,1,-2,1));   // Force			newton	(m*kg)/s^2

	/** The pressure unit pascal (Pa).
		<p>Pa is equal to N/m<sup>2</sup>
		or is expressed in SI units as kg/m&#183;s<sup>2</sup> */
	public final static Unit  Pa	   = new Unit("Pa",  createType(0,0,0,0,0,0,1,-2,-1));   // Pressure			pascal	kg/(m*s^2)

	/** The energy unit joule (J).
		<p>joule is equal to N&#183;m
		or is expressed in SI units as m<sup>2</sup>&#183;kg/s<sup>2 */
	public final static Unit  J 	   = new Unit("J",   createType(0,0,0,0,0,0,1,-2,2));   // Energy	   	 	joule 	(m^2*kg)/s^2

	/** The power unit watt (W).
		<p>watt is equal to J/s
		or is expressed in SI units as m<sup>2</sup>&#183;kg/s<sup>3</sup> */
	public final static Unit  W 	   = new Unit("W",   createType(0,0,0,0,0,0,1,-3,2));   // Power			watt 	(m^2*kg)/s^3

	/** The electric charge unit coulomb (C).
		<p>coulomb is expressed in SI units as
		s&#183;A */
	public final static Unit  C 	   = new Unit("C",   createType(0,0,0,0,1,0,0,1,0));   // Charge  	 	coulumb s*A

	/** The electric potential difference unit volt (V).
		<p>volt is equal to W/A
		or is expressed in SI units as
		m<sup>2</sup>&#183;kg/s<sup>3</sup>&#183;A */
	public final static Unit  V 	   = new Unit("V",   createType(0,0,0,0,-1,0,1,-3,2));   // El. Potent.		volt	(m^2*kg)/(s^3*A)

	/** The capacitance unit farad (F).
		<p>farad is equal to C/V
		or is expressed in SI units as
		s<sup>4</sup>&#183;A<sup>2</sup>/m<sup>2</sup>&#183;kg */
	public final static Unit  F 	   = new Unit("F",   createType(0,0,0,0,2,0,-1,4,-2));   // Capacitance		farad	(s^4*A^2)/(m^2*kg)

	/** The electric resistance unit ohm.
		<p>ohm is equal to V/A
		or is expressed in SI units as
		m<sup>2</sup>&#183;kg/s<sup>3</sup>&#183;A<sup>2</sup> */
	public final static Unit  Ohm  	= new Unit("ohm", createType(0,0,0,0,-2,0,1,-3,2));   // Resistance		ohm		(m^2*kg)/(s^3*A^2)

	/** The electric conductance unit siemens (S).
		<p>siemens is equal to A/V
		or is expressed in SI units as
		s<sup>3</sup>&#183;A<sup>2</sup>/m<sup>2</sup>&#183;kg */
	public final static Unit  S 	   = new Unit("S",   createType(0,0,0,0,2,0,-1,3,-2));   // Conductance		siemens	(s^3*A^2)/(m^2*kg)

	/** The magnetic flux unit weber (Wb).
		<p>weber is equal to V&#183;s
		or is expressed in SI units as
		m<sup>2</sup>&#183;kg/s<sup>2</sup>&#183;A */
	public final static Unit  Wb	   = new Unit("Wb",  createType(0,0,0,0,-1,0,1,-2,2));   // Magn. Flux		weber	(m^2*kg)/(s^2*A)

	/** The magnetic flux density unit tesla (T).
		<p>tesla is equal to Wb/m<sup>2</sup>
		or is expressed in SI units as
		kg/s<sup>2</sup>&#183;A */
	public final static Unit  T 	   = new Unit("T",   createType(0,0,0,0,-1,0,1,-2,0));   // Magn. Flux Dens.	tesla	kg/(s^2*A)

	/** The illuminance unit lux (lx).
		<p>lux is expressed in SI units as
		cd/m<sup>2</sup> */
	public final static Unit  lx	   = new Unit("lx",  createType(0,0,1,0,0,0,0,0,-2));   // Illuminace 	  lux		cd/m^2

	/** The absorbed dose unit gray (Gy).
		<p>Gy is equal to J/kg
		or is expressed in SI units as m<sup>2</sup>/s<sup>2</sup> */
	public final static Unit  Gy	   = new Unit("Gy",  createType(0,0,0,0,0,0,0,-2,2));   // Absorbed dose	gray	m^2/s^2

	/** The catalytic activity unit katal (kat).
		<p>katal is expressed in SI units as
		mol/s */
	public final static Unit  kat  	= new Unit("kat", createType(0,0,0,1,0,0,0,-1,0));   // Catalytic Act.	katal	mol/s



	/** The angle unit radians (rad) */
	public final static Unit  rad  	= new Unit("rad", createType(0,1,0,0,0,0,0,0,0));   // Angle			radians rad



	/** An array containing all units defined. The first seven items must be
	 * m, s, kg, K, A, mol, cd, rad in this order!
	 */
	private final static Unit [] allUnits = new Unit[] { m, s, kg, K, A, mol, cd, rad, m_s, m_s2, m2, m3, Hz, N, Pa, J, W, C, V, F, Ohm, S, Wb, T, lx, Gy, kat, unity};
	private static Hashtable	base;

	private String  				name;
	private long					 type;

	/**
	 * Creates a new <tt>Unit</tt> instance.
	 *
	 * @param name the name of the <tt>Unit</tt>
	 * @param type the type of the <tt>Unit</tt>
	 */
	private Unit(String name, long type)
	{
		this.name = name;
		this.type = type;
		//System.out.println( name + " " + Long.toHexString( type ) );
	}

	/**
	 * Create a type field from the base SI unit exponent values.
	 *
	 */
	private static long createType(int x, int rad, int cd, int mol, int A, int K, int kg, int s, int m)
	{
		return (((ZERO + m)&MASK) << m_SHIFT) |
			   (((ZERO + s)&MASK) << s_SHIFT) |
			   (((ZERO + kg)&MASK) << kg_SHIFT) |
			   (((ZERO + K)&MASK) << K_SHIFT) |
			   (((ZERO + A)&MASK) << A_SHIFT) |
			   (((ZERO + mol)&MASK) << mol_SHIFT) |
			   (((ZERO + cd)&MASK) << cd_SHIFT) |
			   (((ZERO + rad)&MASK) << rad_SHIFT) |
			   (((long)x) << x_SHIFT);
	}