com.ibm.icu.math.MathContext Maven / Gradle / Ivy
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/* Generated from 'MathContext.nrx' 8 Sep 2000 11:07:48 [v2.00] */
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package com.ibm.icu.math;
/* ------------------------------------------------------------------ */
/* MathContext -- Math context settings */
/* ------------------------------------------------------------------ */
/* Copyright IBM Corporation, 1997, 2000, 2005, 2007. All Rights Reserved. */
/* */
/* The MathContext object encapsulates the settings used by the */
/* BigDecimal class; it could also be used by other arithmetics. */
/* ------------------------------------------------------------------ */
/* Notes: */
/* */
/* 1. The properties are checked for validity on construction, so */
/* the BigDecimal class may assume that they are correct. */
/* ------------------------------------------------------------------ */
/* Author: Mike Cowlishaw */
/* 1997.09.03 Initial version (edited from netrexx.lang.RexxSet) */
/* 1997.09.12 Add lostDigits property */
/* 1998.05.02 Make the class immutable and final; drop set methods */
/* 1998.06.05 Add Round (rounding modes) property */
/* 1998.06.25 Rename from DecimalContext; allow digits=0 */
/* 1998.10.12 change to com.ibm.icu.math package */
/* 1999.02.06 add javadoc comments */
/* 1999.03.05 simplify; changes from discussion with J. Bloch */
/* 1999.03.13 1.00 release to IBM Centre for Java Technology */
/* 1999.07.10 1.04 flag serialization unused */
/* 2000.01.01 1.06 copyright update */
/* ------------------------------------------------------------------ */
/**
* The MathContext immutable class encapsulates the
* settings understood by the operator methods of the {@link BigDecimal}
* class (and potentially other classes). Operator methods are those
* that effect an operation on a number or a pair of numbers.
*
* The settings, which are not base-dependent, comprise:
*
* digits:
* the number of digits (precision) to be used for an operation
* form:
* the form of any exponent that results from the operation
* lostDigits:
* whether checking for lost digits is enabled
* roundingMode:
* the algorithm to be used for rounding.
*
*
* When provided, a MathContext object supplies the
* settings for an operation directly.
*
* When MathContext.DEFAULT is provided for a
* MathContext parameter then the default settings are used
* (9, SCIENTIFIC, false, ROUND_HALF_UP).
*
* In the BigDecimal class, all methods which accept a
* MathContext object defaults) also have a version of the
* method which does not accept a MathContext parameter. These versions
* carry out unlimited precision fixed point arithmetic (as though the
* settings were (0, PLAIN, false, ROUND_HALF_UP).
*
* The instance variables are shared with default access (so they are
* directly accessible to the BigDecimal class), but must
* never be changed.
*
* The rounding mode constants have the same names and values as the
* constants of the same name in java.math.BigDecimal, to
* maintain compatibility with earlier versions of
* BigDecimal.
*
* @see BigDecimal
* @author Mike Cowlishaw
* @stable ICU 2.0
*/
public final class MathContext implements java.io.Serializable{
//private static final java.lang.String $0="MathContext.nrx";
/* ----- Properties ----- */
/* properties public constant */
/**
* Plain (fixed point) notation, without any exponent.
* Used as a setting to control the form of the result of a
* BigDecimal operation.
* A zero result in plain form may have a decimal part of one or
* more zeros.
*
* @see #ENGINEERING
* @see #SCIENTIFIC
* @stable ICU 2.0
*/
public static final int PLAIN=0; // [no exponent]
/**
* Standard floating point notation (with scientific exponential
* format, where there is one digit before any decimal point).
* Used as a setting to control the form of the result of a
* BigDecimal operation.
* A zero result in plain form may have a decimal part of one or
* more zeros.
*
* @see #ENGINEERING
* @see #PLAIN
* @stable ICU 2.0
*/
public static final int SCIENTIFIC=1; // 1 digit before .
/**
* Standard floating point notation (with engineering exponential
* format, where the power of ten is a multiple of 3).
* Used as a setting to control the form of the result of a
* BigDecimal operation.
* A zero result in plain form may have a decimal part of one or
* more zeros.
*
* @see #PLAIN
* @see #SCIENTIFIC
* @stable ICU 2.0
*/
public static final int ENGINEERING=2; // 1-3 digits before .
// The rounding modes match the original BigDecimal class values
/**
* Rounding mode to round to a more positive number.
* Used as a setting to control the rounding mode used during a
* BigDecimal operation.
*
* If any of the discarded digits are non-zero then the result
* should be rounded towards the next more positive digit.
* @stable ICU 2.0
*/
public static final int ROUND_CEILING=2;
/**
* Rounding mode to round towards zero.
* Used as a setting to control the rounding mode used during a
* BigDecimal operation.
*
* All discarded digits are ignored (truncated). The result is
* neither incremented nor decremented.
* @stable ICU 2.0
*/
public static final int ROUND_DOWN=1;
/**
* Rounding mode to round to a more negative number.
* Used as a setting to control the rounding mode used during a
* BigDecimal operation.
*
* If any of the discarded digits are non-zero then the result
* should be rounded towards the next more negative digit.
* @stable ICU 2.0
*/
public static final int ROUND_FLOOR=3;
/**
* Rounding mode to round to nearest neighbor, where an equidistant
* value is rounded down.
* Used as a setting to control the rounding mode used during a
* BigDecimal operation.
*
* If the discarded digits represent greater than half (0.5 times)
* the value of a one in the next position then the result should be
* rounded up (away from zero). Otherwise the discarded digits are
* ignored.
* @stable ICU 2.0
*/
public static final int ROUND_HALF_DOWN=5;
/**
* Rounding mode to round to nearest neighbor, where an equidistant
* value is rounded to the nearest even neighbor.
* Used as a setting to control the rounding mode used during a
* BigDecimal operation.
*
* If the discarded digits represent greater than half (0.5 times)
* the value of a one in the next position then the result should be
* rounded up (away from zero). If they represent less than half,
* then the result should be rounded down.
*
* Otherwise (they represent exactly half) the result is rounded
* down if its rightmost digit is even, or rounded up if its
* rightmost digit is odd (to make an even digit).
* @stable ICU 2.0
*/
public static final int ROUND_HALF_EVEN=6;
/**
* Rounding mode to round to nearest neighbor, where an equidistant
* value is rounded up.
* Used as a setting to control the rounding mode used during a
* BigDecimal operation.
*
* If the discarded digits represent greater than or equal to half
* (0.5 times) the value of a one in the next position then the result
* should be rounded up (away from zero). Otherwise the discarded
* digits are ignored.
* @stable ICU 2.0
*/
public static final int ROUND_HALF_UP=4;
/**
* Rounding mode to assert that no rounding is necessary.
* Used as a setting to control the rounding mode used during a
* BigDecimal operation.
*
* Rounding (potential loss of information) is not permitted.
* If any of the discarded digits are non-zero then an
* ArithmeticException should be thrown.
* @stable ICU 2.0
*/
public static final int ROUND_UNNECESSARY=7;
/**
* Rounding mode to round away from zero.
* Used as a setting to control the rounding mode used during a
* BigDecimal operation.
*
* If any of the discarded digits are non-zero then the result will
* be rounded up (away from zero).
* @stable ICU 2.0
*/
public static final int ROUND_UP=0;
/* properties shared */
/**
* The number of digits (precision) to be used for an operation.
* A value of 0 indicates that unlimited precision (as many digits
* as are required) will be used.
*
* The {@link BigDecimal} operator methods use this value to
* determine the precision of results.
* Note that leading zeros (in the integer part of a number) are
* never significant.
*
* digits will always be non-negative.
*
* @serial
*/
int digits;
/**
* The form of results from an operation.
*
* The {@link BigDecimal} operator methods use this value to
* determine the form of results, in particular whether and how
* exponential notation should be used.
*
* @see #ENGINEERING
* @see #PLAIN
* @see #SCIENTIFIC
* @serial
*/
int form; // values for this must fit in a byte
/**
* Controls whether lost digits checking is enabled for an
* operation.
* Set to true to enable checking, or
* to false to disable checking.
*
* When enabled, the {@link BigDecimal} operator methods check
* the precision of their operand or operands, and throw an
* ArithmeticException if an operand is more precise
* than the digits setting (that is, digits would be lost).
* When disabled, operands are rounded to the specified digits.
*
* @serial
*/
boolean lostDigits;
/**
* The rounding algorithm to be used for an operation.
*
* The {@link BigDecimal} operator methods use this value to
* determine the algorithm to be used when non-zero digits have to
* be discarded in order to reduce the precision of a result.
* The value must be one of the public constants whose name starts
* with ROUND_.
*
* @see #ROUND_CEILING
* @see #ROUND_DOWN
* @see #ROUND_FLOOR
* @see #ROUND_HALF_DOWN
* @see #ROUND_HALF_EVEN
* @see #ROUND_HALF_UP
* @see #ROUND_UNNECESSARY
* @see #ROUND_UP
* @serial
*/
int roundingMode;
/* properties private constant */
// default settings
private static final int DEFAULT_FORM=SCIENTIFIC;
private static final int DEFAULT_DIGITS=9;
private static final boolean DEFAULT_LOSTDIGITS=false;
private static final int DEFAULT_ROUNDINGMODE=ROUND_HALF_UP;
/* properties private constant */
private static final int MIN_DIGITS=0; // smallest value for DIGITS.
private static final int MAX_DIGITS=999999999; // largest value for DIGITS. If increased,
// the BigDecimal class may need update.
// list of valid rounding mode values, most common two first
private static final int ROUNDS[]=new int[]{ROUND_HALF_UP,ROUND_UNNECESSARY,ROUND_CEILING,ROUND_DOWN,ROUND_FLOOR,ROUND_HALF_DOWN,ROUND_HALF_EVEN,ROUND_UP};
private static final java.lang.String ROUNDWORDS[]=new java.lang.String[]{"ROUND_HALF_UP","ROUND_UNNECESSARY","ROUND_CEILING","ROUND_DOWN","ROUND_FLOOR","ROUND_HALF_DOWN","ROUND_HALF_EVEN","ROUND_UP"}; // matching names of the ROUNDS values
/* properties private constant unused */
// Serialization version
private static final long serialVersionUID=7163376998892515376L;
/* properties public constant */
/**
* A MathContext object initialized to the default
* settings for general-purpose arithmetic. That is,
* digits=9 form=SCIENTIFIC lostDigits=false
* roundingMode=ROUND_HALF_UP.
*
* @see #SCIENTIFIC
* @see #ROUND_HALF_UP
* @stable ICU 2.0
*/
public static final com.ibm.icu.math.MathContext DEFAULT=new com.ibm.icu.math.MathContext(DEFAULT_DIGITS,DEFAULT_FORM,DEFAULT_LOSTDIGITS,DEFAULT_ROUNDINGMODE);
/* ----- Constructors ----- */
/**
* Constructs a new MathContext with a specified
* precision.
* The other settings are set to the default values
* (see {@link #DEFAULT}).
*
* An IllegalArgumentException is thrown if the
* setdigits parameter is out of range
* (<0 or >999999999).
*
* @param setdigits The int digits setting
* for this MathContext.
* @throws IllegalArgumentException parameter out of range.
* @stable ICU 2.0
*/
public MathContext(int setdigits){
this(setdigits,DEFAULT_FORM,DEFAULT_LOSTDIGITS,DEFAULT_ROUNDINGMODE);
return;}
/**
* Constructs a new MathContext with a specified
* precision and form.
* The other settings are set to the default values
* (see {@link #DEFAULT}).
*
* An IllegalArgumentException is thrown if the
* setdigits parameter is out of range
* (<0 or >999999999), or if the value given for the
* setform parameter is not one of the appropriate
* constants.
*
* @param setdigits The int digits setting
* for this MathContext.
* @param setform The int form setting
* for this MathContext.
* @throws IllegalArgumentException parameter out of range.
* @stable ICU 2.0
*/
public MathContext(int setdigits,int setform){
this(setdigits,setform,DEFAULT_LOSTDIGITS,DEFAULT_ROUNDINGMODE);
return;}
/**
* Constructs a new MathContext with a specified
* precision, form, and lostDigits setting.
* The roundingMode setting is set to its default value
* (see {@link #DEFAULT}).
*
* An IllegalArgumentException is thrown if the
* setdigits parameter is out of range
* (<0 or >999999999), or if the value given for the
* setform parameter is not one of the appropriate
* constants.
*
* @param setdigits The int digits setting
* for this MathContext.
* @param setform The int form setting
* for this MathContext.
* @param setlostdigits The boolean lostDigits
* setting for this MathContext.
* @throws IllegalArgumentException parameter out of range.
* @stable ICU 2.0
*/
public MathContext(int setdigits,int setform,boolean setlostdigits){
this(setdigits,setform,setlostdigits,DEFAULT_ROUNDINGMODE);
return;}
/**
* Constructs a new MathContext with a specified
* precision, form, lostDigits, and roundingMode setting.
*
* An IllegalArgumentException is thrown if the
* setdigits parameter is out of range
* (<0 or >999999999), or if the value given for the
* setform or setroundingmode parameters is
* not one of the appropriate constants.
*
* @param setdigits The int digits setting
* for this MathContext.
* @param setform The int form setting
* for this MathContext.
* @param setlostdigits The boolean lostDigits
* setting for this MathContext.
* @param setroundingmode The int roundingMode setting
* for this MathContext.
* @throws IllegalArgumentException parameter out of range.
* @stable ICU 2.0
*/
public MathContext(int setdigits,int setform,boolean setlostdigits,int setroundingmode){super();
// set values, after checking
if (setdigits!=DEFAULT_DIGITS)
{
if (setdigitsMAX_DIGITS)
throw new java.lang.IllegalArgumentException("Digits too large:"+" "+setdigits);
}
{/*select*/
if (setform==SCIENTIFIC){
// [most common]
}else if (setform==ENGINEERING){
}else if (setform==PLAIN){
}else{
throw new java.lang.IllegalArgumentException("Bad form value:"+" "+setform);
}
}
if ((!(isValidRound(setroundingmode))))
throw new java.lang.IllegalArgumentException("Bad roundingMode value:"+" "+setroundingmode);
digits=setdigits;
form=setform;
lostDigits=setlostdigits; // [no bad value possible]
roundingMode=setroundingmode;
return;}
/**
* Returns the digits setting.
* This value is always non-negative.
*
* @return an int which is the value of the digits
* setting
* @stable ICU 2.0
*/
public int getDigits(){
return digits;
}
/**
* Returns the form setting.
* This will be one of
* {@link #ENGINEERING},
* {@link #PLAIN}, or
* {@link #SCIENTIFIC}.
*
* @return an int which is the value of the form setting
* @stable ICU 2.0
*/
public int getForm(){
return form;
}
/**
* Returns the lostDigits setting.
* This will be either true (enabled) or
* false (disabled).
*
* @return a boolean which is the value of the lostDigits
* setting
* @stable ICU 2.0
*/
public boolean getLostDigits(){
return lostDigits;
}
/**
* Returns the roundingMode setting.
* This will be one of
* {@link #ROUND_CEILING},
* {@link #ROUND_DOWN},
* {@link #ROUND_FLOOR},
* {@link #ROUND_HALF_DOWN},
* {@link #ROUND_HALF_EVEN},
* {@link #ROUND_HALF_UP},
* {@link #ROUND_UNNECESSARY}, or
* {@link #ROUND_UP}.
*
* @return an int which is the value of the roundingMode
* setting
* @stable ICU 2.0
*/
public int getRoundingMode(){
return roundingMode;
}
/** Returns the MathContext as a readable string.
* The String returned represents the settings of the
* MathContext object as four blank-delimited words
* separated by a single blank and with no leading or trailing blanks,
* as follows:
*
* -
*
digits=, immediately followed by
* the value of the digits setting as a numeric word.
* -
*
form=, immediately followed by
* the value of the form setting as an uppercase word
* (one of SCIENTIFIC, PLAIN, or
* ENGINEERING).
* -
*
lostDigits=, immediately followed by
* the value of the lostDigits setting
* (1 if enabled, 0 if disabled).
* -
*
roundingMode=, immediately followed by
* the value of the roundingMode setting as a word.
* This word will be the same as the name of the corresponding public
* constant.
*
*
* For example:
*
* digits=9 form=SCIENTIFIC lostDigits=0 roundingMode=ROUND_HALF_UP
*
*
* Additional words may be appended to the result of
* toString in the future if more properties are added
* to the class.
*
* @return a String representing the context settings.
* @stable ICU 2.0
*/
@Override
public java.lang.String toString(){
java.lang.String formstr=null;
int r=0;
java.lang.String roundword=null;
{/*select*/
if (form==SCIENTIFIC)
formstr="SCIENTIFIC";
else if (form==ENGINEERING)
formstr="ENGINEERING";
else{
formstr="PLAIN";/* form=PLAIN */
}
}
{int $1=ROUNDS.length;r=0;r:for(;$1>0;$1--,r++){
if (roundingMode==ROUNDS[r])
{
roundword=ROUNDWORDS[r];
break r;
}
}
}/*r*/
return "digits="+digits+" "+"form="+formstr+" "+"lostDigits="+(lostDigits?"1":"0")+" "+"roundingMode="+roundword;
}
/* Test whether round is valid. */
// This could be made shared for use by BigDecimal for setScale.
private static boolean isValidRound(int testround){
int r=0;
{int $2=ROUNDS.length;for(r=0;$2>0;$2--,r++){
if (testround==ROUNDS[r])
return true;
}
}/*r*/
return false;
}
}