org.apache.commons.lang.math
Class NumberUtils

java.lang.Object
  org.apache.commons.lang.math.NumberUtils

public class NumberUtils

extends java.lang.Object

Provides extra functionality for Java Number classes.

Since:

2.0

Version:

$Id: NumberUtils.java 609475 2008-01-06 23:58:59Z bayard $

Author:

Rand McNeely, Stephen Colebourne, Steve Downey, Eric Pugh, Phil Steitz, Matthew Hawthorne, Gary Gregory, Fredrik Westermarck

Field Summary

static java.lang.Byte	BYTE_MINUS_ONE Reusable Byte constant for minus one.
static java.lang.Byte	BYTE_ONE Reusable Byte constant for one.
static java.lang.Byte	BYTE_ZERO Reusable Byte constant for zero.
static java.lang.Double	DOUBLE_MINUS_ONE Reusable Double constant for minus one.
static java.lang.Double	DOUBLE_ONE Reusable Double constant for one.
static java.lang.Double	DOUBLE_ZERO Reusable Double constant for zero.
static java.lang.Float	FLOAT_MINUS_ONE Reusable Float constant for minus one.
static java.lang.Float	FLOAT_ONE Reusable Float constant for one.
static java.lang.Float	FLOAT_ZERO Reusable Float constant for zero.
static java.lang.Integer	INTEGER_MINUS_ONE Reusable Integer constant for minus one.
static java.lang.Integer	INTEGER_ONE Reusable Integer constant for one.
static java.lang.Integer	INTEGER_ZERO Reusable Integer constant for zero.
static java.lang.Long	LONG_MINUS_ONE Reusable Long constant for minus one.
static java.lang.Long	LONG_ONE Reusable Long constant for one.
static java.lang.Long	LONG_ZERO Reusable Long constant for zero.
static java.lang.Short	SHORT_MINUS_ONE Reusable Short constant for minus one.
static java.lang.Short	SHORT_ONE Reusable Short constant for one.
static java.lang.Short	SHORT_ZERO Reusable Short constant for zero.

Constructor Summary

NumberUtils()
NumberUtils instances should NOT be constructed in standard programming.

Method Summary

static int	compare(double lhs, double rhs) Compares two doubles for order.
static int	compare(float lhs, float rhs) Compares two floats for order.
static java.math.BigDecimal	createBigDecimal(java.lang.String str) Convert a String to a BigDecimal.
static java.math.BigInteger	createBigInteger(java.lang.String str) Convert a String to a BigInteger.
static java.lang.Double	createDouble(java.lang.String str) Convert a String to a Double.
static java.lang.Float	createFloat(java.lang.String str) Convert a String to a Float.
static java.lang.Integer	createInteger(java.lang.String str) Convert a String to a Integer, handling hex and octal notations.
static java.lang.Long	createLong(java.lang.String str) Convert a String to a Long.
static java.lang.Number	createNumber(java.lang.String str) Turns a string value into a java.lang.Number.
static boolean	isDigits(java.lang.String str) Checks whether the String contains only digit characters.
static boolean	isNumber(java.lang.String str) Checks whether the String a valid Java number.
static byte	max(byte[] array) Returns the maximum value in an array.
static byte	max(byte a, byte b, byte c) Gets the maximum of three byte values.
static double	max(double[] array) Returns the maximum value in an array.
static double	max(double a, double b, double c) Gets the maximum of three double values.
static float	max(float[] array) Returns the maximum value in an array.
static float	max(float a, float b, float c) Gets the maximum of three float values.
static int	max(int[] array) Returns the maximum value in an array.
static int	max(int a, int b, int c) Gets the maximum of three int values.
static long	max(long[] array) Returns the maximum value in an array.
static long	max(long a, long b, long c) Gets the maximum of three long values.
static short	max(short[] array) Returns the maximum value in an array.
static short	max(short a, short b, short c) Gets the maximum of three short values.
static byte	min(byte[] array) Returns the minimum value in an array.
static byte	min(byte a, byte b, byte c) Gets the minimum of three byte values.
static double	min(double[] array) Returns the minimum value in an array.
static double	min(double a, double b, double c) Gets the minimum of three double values.
static float	min(float[] array) Returns the minimum value in an array.
static float	min(float a, float b, float c) Gets the minimum of three float values.
static int	min(int[] array) Returns the minimum value in an array.
static int	min(int a, int b, int c) Gets the minimum of three int values.
static long	min(long[] array) Returns the minimum value in an array.
static long	min(long a, long b, long c) Gets the minimum of three long values.
static short	min(short[] array) Returns the minimum value in an array.
static short	min(short a, short b, short c) Gets the minimum of three short values.
static int	stringToInt(java.lang.String str) Deprecated. Use toInt(String) This method will be removed in Commons Lang 3.0
static int	stringToInt(java.lang.String str, int defaultValue) Deprecated. Use toInt(String, int) This method will be removed in Commons Lang 3.0
static double	toDouble(java.lang.String str) Convert a String to a double, returning 0.0d if the conversion fails.
static double	toDouble(java.lang.String str, double defaultValue) Convert a String to a double, returning a default value if the conversion fails.
static float	toFloat(java.lang.String str) Convert a String to a float, returning 0.0f if the conversion fails.
static float	toFloat(java.lang.String str, float defaultValue) Convert a String to a float, returning a default value if the conversion fails.
static int	toInt(java.lang.String str) Convert a String to an int, returning zero if the conversion fails.
static int	toInt(java.lang.String str, int defaultValue) Convert a String to an int, returning a default value if the conversion fails.
static long	toLong(java.lang.String str) Convert a String to a long, returning zero if the conversion fails.
static long	toLong(java.lang.String str, long defaultValue) Convert a String to a long, returning a default value if the conversion fails.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LONG_ZERO

public static final java.lang.Long LONG_ZERO

Reusable Long constant for zero.

LONG_ONE

public static final java.lang.Long LONG_ONE

Reusable Long constant for one.

LONG_MINUS_ONE

public static final java.lang.Long LONG_MINUS_ONE

Reusable Long constant for minus one.

INTEGER_ZERO

public static final java.lang.Integer INTEGER_ZERO

Reusable Integer constant for zero.

INTEGER_ONE

public static final java.lang.Integer INTEGER_ONE

Reusable Integer constant for one.

INTEGER_MINUS_ONE

public static final java.lang.Integer INTEGER_MINUS_ONE

Reusable Integer constant for minus one.

SHORT_ZERO

public static final java.lang.Short SHORT_ZERO

Reusable Short constant for zero.

SHORT_ONE

public static final java.lang.Short SHORT_ONE

Reusable Short constant for one.

SHORT_MINUS_ONE

public static final java.lang.Short SHORT_MINUS_ONE

Reusable Short constant for minus one.

BYTE_ZERO

public static final java.lang.Byte BYTE_ZERO

Reusable Byte constant for zero.

BYTE_ONE

public static final java.lang.Byte BYTE_ONE

Reusable Byte constant for one.

BYTE_MINUS_ONE

public static final java.lang.Byte BYTE_MINUS_ONE

Reusable Byte constant for minus one.

DOUBLE_ZERO

public static final java.lang.Double DOUBLE_ZERO

Reusable Double constant for zero.

DOUBLE_ONE

public static final java.lang.Double DOUBLE_ONE

Reusable Double constant for one.

DOUBLE_MINUS_ONE

public static final java.lang.Double DOUBLE_MINUS_ONE

Reusable Double constant for minus one.

FLOAT_ZERO

public static final java.lang.Float FLOAT_ZERO

Reusable Float constant for zero.

FLOAT_ONE

public static final java.lang.Float FLOAT_ONE

Reusable Float constant for one.

FLOAT_MINUS_ONE

public static final java.lang.Float FLOAT_MINUS_ONE

Reusable Float constant for minus one.

Constructor Detail

NumberUtils

public NumberUtils()

NumberUtils instances should NOT be constructed in standard programming. Instead, the class should be used as NumberUtils.stringToInt("6");.

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Detail

stringToInt

public static int stringToInt(java.lang.String str)

Deprecated. Use toInt(String) This method will be removed in Commons Lang 3.0

Convert a String to an int, returning zero if the conversion fails.

If the string is null, zero is returned.

   NumberUtils.stringToInt(null) = 0
   NumberUtils.stringToInt("")   = 0
   NumberUtils.stringToInt("1")  = 1
 

Parameters:

str - the string to convert, may be null

Returns:

the int represented by the string, or zero if conversion fails

toInt

public static int toInt(java.lang.String str)

Convert a String to an int, returning zero if the conversion fails.

If the string is null, zero is returned.

   NumberUtils.toInt(null) = 0
   NumberUtils.toInt("")   = 0
   NumberUtils.toInt("1")  = 1
 

Parameters:

str - the string to convert, may be null

Returns:

the int represented by the string, or zero if conversion fails

Since:

2.1

stringToInt

public static int stringToInt(java.lang.String str,
                              int defaultValue)

Deprecated. Use toInt(String, int) This method will be removed in Commons Lang 3.0

Convert a String to an int, returning a default value if the conversion fails.

If the string is null, the default value is returned.

   NumberUtils.stringToInt(null, 1) = 1
   NumberUtils.stringToInt("", 1)   = 1
   NumberUtils.stringToInt("1", 0)  = 1
 

Parameters:

str - the string to convert, may be null

defaultValue - the default value

Returns:

the int represented by the string, or the default if conversion fails

toInt

public static int toInt(java.lang.String str,
                        int defaultValue)

Convert a String to an int, returning a default value if the conversion fails.

If the string is null, the default value is returned.

   NumberUtils.toInt(null, 1) = 1
   NumberUtils.toInt("", 1)   = 1
   NumberUtils.toInt("1", 0)  = 1
 

Parameters:

str - the string to convert, may be null

defaultValue - the default value

Returns:

the int represented by the string, or the default if conversion fails

Since:

2.1

toLong

public static long toLong(java.lang.String str)

Convert a String to a long, returning zero if the conversion fails.

If the string is null, zero is returned.

   NumberUtils.toLong(null) = 0L
   NumberUtils.toLong("")   = 0L
   NumberUtils.toLong("1")  = 1L
 

Parameters:

str - the string to convert, may be null

Returns:

the long represented by the string, or 0 if conversion fails

Since:

2.1

toLong

public static long toLong(java.lang.String str,
                          long defaultValue)

Convert a String to a long, returning a default value if the conversion fails.

If the string is null, the default value is returned.

   NumberUtils.toLong(null, 1L) = 1L
   NumberUtils.toLong("", 1L)   = 1L
   NumberUtils.toLong("1", 0L)  = 1L
 

Parameters:

str - the string to convert, may be null

defaultValue - the default value

Returns:

the long represented by the string, or the default if conversion fails

Since:

2.1

toFloat

public static float toFloat(java.lang.String str)

Convert a String to a float, returning 0.0f if the conversion fails.

If the string str is null, 0.0f is returned.

   NumberUtils.toFloat(null)   = 0.0f
   NumberUtils.toFloat("")     = 0.0f
   NumberUtils.toFloat("1.5")  = 1.5f
 

Parameters:

str - the string to convert, may be null

Returns:

the float represented by the string, or 0.0f if conversion fails

Since:

2.1

toFloat

public static float toFloat(java.lang.String str,
                            float defaultValue)

Convert a String to a float, returning a default value if the conversion fails.

If the string str is null, the default value is returned.

   NumberUtils.toFloat(null, 1.1f)   = 1.0f
   NumberUtils.toFloat("", 1.1f)     = 1.1f
   NumberUtils.toFloat("1.5", 0.0f)  = 1.5f
 

Parameters:

str - the string to convert, may be null

defaultValue - the default value

Returns:

the float represented by the string, or defaultValue if conversion fails

Since:

2.1

toDouble

public static double toDouble(java.lang.String str)

Convert a String to a double, returning 0.0d if the conversion fails.

If the string str is null, 0.0d is returned.

   NumberUtils.toDouble(null)   = 0.0d
   NumberUtils.toDouble("")     = 0.0d
   NumberUtils.toDouble("1.5")  = 1.5d
 

Parameters:

str - the string to convert, may be null

Returns:

the double represented by the string, or 0.0d if conversion fails

Since:

2.1

toDouble

public static double toDouble(java.lang.String str,
                              double defaultValue)

Convert a String to a double, returning a default value if the conversion fails.

If the string str is null, the default value is returned.

   NumberUtils.toDouble(null, 1.1d)   = 1.1d
   NumberUtils.toDouble("", 1.1d)     = 1.1d
   NumberUtils.toDouble("1.5", 0.0d)  = 1.5d
 

Parameters:

str - the string to convert, may be null

defaultValue - the default value

Returns:

the double represented by the string, or defaultValue if conversion fails

Since:

2.1

createNumber

public static java.lang.Number createNumber(java.lang.String str)
                                     throws java.lang.NumberFormatException

Turns a string value into a java.lang.Number.

First, the value is examined for a type qualifier on the end ('f','F','d','D','l','L'). If it is found, it starts trying to create successively larger types from the type specified until one is found that can represent the value.

If a type specifier is not found, it will check for a decimal point and then try successively larger types from Integer to BigInteger and from Float to BigDecimal.

If the string starts with 0x or -0x, it will be interpreted as a hexadecimal integer. Values with leading 0's will not be interpreted as octal.

Returns null if the string is null.

This method does not trim the input string, i.e., strings with leading or trailing spaces will generate NumberFormatExceptions.

Parameters:

str - String containing a number, may be null

Returns:

Number created from the string

Throws:

java.lang.NumberFormatException - if the value cannot be converted

createFloat

public static java.lang.Float createFloat(java.lang.String str)

Convert a String to a Float.

Returns null if the string is null.

Parameters:

str - a String to convert, may be null

Returns:

converted Float

Throws:

java.lang.NumberFormatException - if the value cannot be converted

createDouble

public static java.lang.Double createDouble(java.lang.String str)

Convert a String to a Double.

Returns null if the string is null.

Parameters:

str - a String to convert, may be null

Returns:

converted Double

Throws:

java.lang.NumberFormatException - if the value cannot be converted

createInteger

public static java.lang.Integer createInteger(java.lang.String str)

Convert a String to a Integer, handling hex and octal notations.

Returns null if the string is null.

Parameters:

str - a String to convert, may be null

Returns:

converted Integer

Throws:

java.lang.NumberFormatException - if the value cannot be converted

createLong

public static java.lang.Long createLong(java.lang.String str)

Convert a String to a Long.

Returns null if the string is null.

Parameters:

str - a String to convert, may be null

Returns:

converted Long

Throws:

java.lang.NumberFormatException - if the value cannot be converted

createBigInteger

public static java.math.BigInteger createBigInteger(java.lang.String str)

Convert a String to a BigInteger.

Returns null if the string is null.

Parameters:

str - a String to convert, may be null

Returns:

converted BigInteger

Throws:

java.lang.NumberFormatException - if the value cannot be converted

createBigDecimal

public static java.math.BigDecimal createBigDecimal(java.lang.String str)

Convert a String to a BigDecimal.

Returns null if the string is null.

Parameters:

str - a String to convert, may be null

Returns:

converted BigDecimal

Throws:

java.lang.NumberFormatException - if the value cannot be converted

min

public static long min(long[] array)

Returns the minimum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

min

public static int min(int[] array)

Returns the minimum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

min

public static short min(short[] array)

Returns the minimum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

min

public static byte min(byte[] array)

Returns the minimum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

min

public static double min(double[] array)

Returns the minimum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

See Also:

IEEE754rUtils for a version of this method that handles NaN differently

min

public static float min(float[] array)

Returns the minimum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

See Also:

IEEE754rUtils for a version of this method that handles NaN differently

max

public static long max(long[] array)

Returns the maximum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

max

public static int max(int[] array)

Returns the maximum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

max

public static short max(short[] array)

Returns the maximum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

max

public static byte max(byte[] array)

Returns the maximum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

max

public static double max(double[] array)

Returns the maximum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

See Also:

IEEE754rUtils for a version of this method that handles NaN differently

max

public static float max(float[] array)

Returns the maximum value in an array.

Parameters:

array - an array, must not be null or empty

Returns:

the minimum value in the array

Throws:

java.lang.IllegalArgumentException - if array is null

java.lang.IllegalArgumentException - if array is empty

See Also:

IEEE754rUtils for a version of this method that handles NaN differently

min

public static long min(long a,
                       long b,
                       long c)

Gets the minimum of three long values.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the smallest of the values

min

public static int min(int a,
                      int b,
                      int c)

Gets the minimum of three int values.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the smallest of the values

min

public static short min(short a,
                        short b,
                        short c)

Gets the minimum of three short values.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the smallest of the values

min

public static byte min(byte a,
                       byte b,
                       byte c)

Gets the minimum of three byte values.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the smallest of the values

min

public static double min(double a,
                         double b,
                         double c)

Gets the minimum of three double values.

If any value is NaN, NaN is returned. Infinity is handled.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the smallest of the values

See Also:

for a version of this method that handles NaN differently

min

public static float min(float a,
                        float b,
                        float c)

Gets the minimum of three float values.

If any value is NaN, NaN is returned. Infinity is handled.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the smallest of the values

See Also:

for a version of this method that handles NaN differently

max

public static long max(long a,
                       long b,
                       long c)

Gets the maximum of three long values.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the largest of the values

max

public static int max(int a,
                      int b,
                      int c)

Gets the maximum of three int values.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the largest of the values

max

public static short max(short a,
                        short b,
                        short c)

Gets the maximum of three short values.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the largest of the values

max

public static byte max(byte a,
                       byte b,
                       byte c)

Gets the maximum of three byte values.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the largest of the values

max

public static double max(double a,
                         double b,
                         double c)

Gets the maximum of three double values.

If any value is NaN, NaN is returned. Infinity is handled.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the largest of the values

See Also:

for a version of this method that handles NaN differently

max

public static float max(float a,
                        float b,
                        float c)

Gets the maximum of three float values.

If any value is NaN, NaN is returned. Infinity is handled.

Parameters:

a - value 1

b - value 2

c - value 3

Returns:

the largest of the values

See Also:

for a version of this method that handles NaN differently

compare

public static int compare(double lhs,
                          double rhs)

Compares two doubles for order.

This method is more comprehensive than the standard Java greater than, less than and equals operators.

• It returns -1 if the first value is less than the second.
• It returns +1 if the first value is greater than the second.
• It returns 0 if the values are equal.

The ordering is as follows, largest to smallest:

• NaN
• Positive infinity
• Maximum double
• Normal positive numbers
• +0.0
• -0.0
• Normal negative numbers
• Minimum double (-Double.MAX_VALUE)
• Negative infinity

Comparing NaN with NaN will return 0.

Parameters:

lhs - the first double

rhs - the second double

Returns:

-1 if lhs is less, +1 if greater, 0 if equal to rhs

compare

public static int compare(float lhs,
                          float rhs)

Compares two floats for order.

This method is more comprehensive than the standard Java greater than, less than and equals operators.

• It returns -1 if the first value is less than the second.
• It returns +1 if the first value is greater than the second.
• It returns 0 if the values are equal.

The ordering is as follows, largest to smallest:

• NaN
• Positive infinity
• Maximum float
• Normal positive numbers
• +0.0
• -0.0
• Normal negative numbers
• Minimum float (-Float.MAX_VALUE)
• Negative infinity

Comparing NaN with NaN will return 0.

Parameters:

lhs - the first float

rhs - the second float

Returns:

-1 if lhs is less, +1 if greater, 0 if equal to rhs

isDigits

public static boolean isDigits(java.lang.String str)

Checks whether the String contains only digit characters.

Null and empty String will return false.

Parameters:

str - the String to check

Returns:

true if str contains only unicode numeric

isNumber

public static boolean isNumber(java.lang.String str)

Checks whether the String a valid Java number.

Valid numbers include hexadecimal marked with the 0x qualifier, scientific notation and numbers marked with a type qualifier (e.g. 123L).

Null and empty String will return false.

Parameters:

str - the String to check

Returns:

true if the string is a correctly formatted number