/*
* Copyright 1998-2014 University Corporation for Atmospheric Research/Unidata
*
* Portions of this software were developed by the Unidata Program at the
* University Corporation for Atmospheric Research.
*
* Access and use of this software shall impose the following obligations
* and understandings on the user. The user is granted the right, without
* any fee or cost, to use, copy, modify, alter, enhance and distribute
* this software, and any derivative works thereof, and its supporting
* documentation for any purpose whatsoever, provided that this entire
* notice appears in all copies of the software, derivative works and
* supporting documentation. Further, UCAR requests that the user credit
* UCAR/Unidata in any publications that result from the use of this
* software or in any product that includes this software. The names UCAR
* and/or Unidata, however, may not be used in any advertising or publicity
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*
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL UCAR/UNIDATA BE LIABLE FOR ANY SPECIAL,
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* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
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*/
package ucar.units;
/**
* Provides support for a database of standard unit prefixes.
*
* @author Steven R. Emmerson
*/
public final class StandardPrefixDB extends PrefixDBImpl {
private static final long serialVersionUID = 1L;
/**
* The singleton instance of this class.
*
* @serial
*/
private static/* final */ StandardPrefixDB instance = null;
/**
* Constructs from nothing.
*
* @throws PrefixExistsException Attempt to redefine a prefix.
*/
private StandardPrefixDB() throws PrefixExistsException {
/*
* SI prefixes:
*/
add("yotta", "Y", 1e24);
add("zetta", "Z", 1e21);
add("exa", "E", 1e18);
add("peta", "P", 1e15);
add("tera", "T", 1e12);
add("giga", "G", 1e9); // 1st syllable pronounced "jig"
// according to "ASTM Designation: E
// 380 - 85: Standard for METRIC
// PRACTICE".
add("mega", "M", 1e6);
add("kilo", "k", 1e3);
add("hecto", "h", 1e2);
add("deca", "da", 1e1); // Spelling according to "ISO 2955:
// Information processing --
// Representation of SI and other units
// in systems with limited character
// sets"
addName("deka", 1e1); // Designation: E 380 - 85: Standard
// for METRIC PRACTICE", "ANSI/IEEE Std
// 260-1978 (Reaffirmed 1985): IEEE
// Standard Letter Symbols for Units of
// Measurement", and NIST Special
// Publication 811, 1995 Edition:
// "Guide for the Use of the
// International System of Units (SI)".
add("deci", "d", 1e-1);
add("centi", "c", 1e-2);
add("milli", "m", 1e-3);
add("micro", "u", 1e-6);
add("nano", "n", 1e-9);
add("pico", "p", 1e-12);
add("femto", "f", 1e-15);
add("atto", "a", 1e-18);
add("zepto", "z", 1e-21);
add("yocto", "y", 1e-24);
}
/**
* Gets an instance of this database.
*
* @return An instance of this database.
* @throws PrefixDBException The instance couldn't be created.
*/
public static synchronized StandardPrefixDB instance() throws PrefixDBException {
if (instance == null) {
try {
instance = new StandardPrefixDB();
} catch (final Exception e) {
throw new PrefixDBException(
"Couldn't create standard prefix-database", e);
}
}
return instance;
}
/**
* Adds a prefix to the database.
*
* @param name The name of the prefix.
* @param symbol The symbol for the prefix.
* @param definition The numeric value of the prefix.
* @throws PrefixExistsException Attempt to redefine an existing prefix.
*/
private void add(final String name, final String symbol,
final double definition) throws PrefixExistsException {
addName(name, definition);
addSymbol(symbol, definition);
}
/**
* Tests this class.
*/
public static void main(final String[] args) throws Exception {
final PrefixDB db = StandardPrefixDB.instance();
System.out.println("db.getPrefixBySymbol(\"cm\") = \""
+ db.getPrefixBySymbol("cm") + '"');
System.out.println("db.getPrefixBySymbol(\"dm\") = \""
+ db.getPrefixBySymbol("dm") + '"');
}
}