org.apache.commons.lang.math

Class NumberUtils


public class NumberUtils
extends Object

Provides extra functionality for Java Number classes.
Version:
$Id: NumberUtils.java 161243 2005-04-14 04:30:28Z ggregory $
Authors:
Henri Yandell
Rand McNeely
Stephen Colebourne
Steve Downey
Eric Pugh
Phil Steitz
Matthew Hawthorne
Gary Gregory
Fredrik Westermarck
Since:
2.0

Field Summary

static Byte
BYTE_MINUS_ONE
Reusable Byte constant for minus one.
static Byte
BYTE_ONE
Reusable Byte constant for one.
static Byte
BYTE_ZERO
Reusable Byte constant for zero.
static Double
DOUBLE_MINUS_ONE
Reusable Double constant for minus one.
static Double
DOUBLE_ONE
Reusable Double constant for one.
static Double
DOUBLE_ZERO
Reusable Double constant for zero.
static Float
FLOAT_MINUS_ONE
Reusable Float constant for minus one.
static Float
FLOAT_ONE
Reusable Float constant for one.
static Float
FLOAT_ZERO
Reusable Float constant for zero.
static Integer
INTEGER_MINUS_ONE
Reusable Integer constant for minus one.
static Integer
INTEGER_ONE
Reusable Integer constant for one.
static Integer
INTEGER_ZERO
Reusable Integer constant for zero.
static Long
LONG_MINUS_ONE
Reusable Long constant for minus one.
static Long
LONG_ONE
Reusable Long constant for one.
static Long
LONG_ZERO
Reusable Long constant for zero.
static Short
SHORT_MINUS_ONE
Reusable Short constant for minus one.
static Short
SHORT_ONE
Reusable Short constant for one.
static 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 BigDecimal
createBigDecimal(String str)
Convert a String to a BigDecimal.
static BigInteger
createBigInteger(String str)
Convert a String to a BigInteger.
static Double
createDouble(String str)
Convert a String to a Double.
static Float
createFloat(String str)
Convert a String to a Float.
static Integer
createInteger(String str)
Convert a String to a Integer, handling hex and octal notations.
static Long
createLong(String str)
Convert a String to a Long.
static Number
createNumber(String str)
Turns a string value into a java.lang.Number.
static boolean
isDigits(String str)
Checks whether the String contains only digit characters.
static boolean
isNumber(String str)
Checks whether the String a valid Java number.
static byte
max(byte a, byte b, byte c)
Gets the maximum of three byte values.
static double
max(double a, double b, double c)
Gets the maximum of three double values.
static double
max(double[] 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 float
max(float[] 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 int
max(int[] 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 long
max(long[] 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 short
max(short[] array)
Returns the maximum value in an array.
static byte
min(byte a, byte b, byte c)
Gets the minimum of three byte values.
static double
min(double a, double b, double c)
Gets the minimum of three double values.
static double
min(double[] 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 float
min(float[] 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 int
min(int[] 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 long
min(long[] 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 short
min(short[] array)
Returns the minimum value in an array.
static int
stringToInt(String str)
Deprecated. Use toInt(String) This method will be removed in Commons Lang 3.0
static int
stringToInt(String str, int defaultValue)
Deprecated. Use toInt(String,int) This method will be removed in Commons Lang 3.0
static double
toDouble(String str)
Convert a String to a double, returning 0.0d if the conversion fails.
static double
toDouble(String str, double defaultValue)
Convert a String to a double, returning a default value if the conversion fails.
static float
toFloat(String str)
Convert a String to a float, returning 0.0f if the conversion fails.
static float
toFloat(String str, float defaultValue)
Convert a String to a float, returning a default value if the conversion fails.
static int
toInt(String str)
Convert a String to an int, returning zero if the conversion fails.
static int
toInt(String str, int defaultValue)
Convert a String to an int, returning a default value if the conversion fails.
static long
toLong(String str)
Convert a String to a long, returning zero if the conversion fails.
static long
toLong(String str, long defaultValue)
Convert a String to a long, returning a default value if the conversion fails.

Field Details

BYTE_MINUS_ONE

public static final Byte BYTE_MINUS_ONE
Reusable Byte constant for minus one.

BYTE_ONE

public static final Byte BYTE_ONE
Reusable Byte constant for one.

BYTE_ZERO

public static final Byte BYTE_ZERO
Reusable Byte constant for zero.

DOUBLE_MINUS_ONE

public static final Double DOUBLE_MINUS_ONE
Reusable Double constant for minus one.

DOUBLE_ONE

public static final Double DOUBLE_ONE
Reusable Double constant for one.

DOUBLE_ZERO

public static final Double DOUBLE_ZERO
Reusable Double constant for zero.

FLOAT_MINUS_ONE

public static final Float FLOAT_MINUS_ONE
Reusable Float constant for minus one.

FLOAT_ONE

public static final Float FLOAT_ONE
Reusable Float constant for one.

FLOAT_ZERO

public static final Float FLOAT_ZERO
Reusable Float constant for zero.

INTEGER_MINUS_ONE

public static final Integer INTEGER_MINUS_ONE
Reusable Integer constant for minus one.

INTEGER_ONE

public static final Integer INTEGER_ONE
Reusable Integer constant for one.

INTEGER_ZERO

public static final Integer INTEGER_ZERO
Reusable Integer constant for zero.

LONG_MINUS_ONE

public static final Long LONG_MINUS_ONE
Reusable Long constant for minus one.

LONG_ONE

public static final Long LONG_ONE
Reusable Long constant for one.

LONG_ZERO

public static final Long LONG_ZERO
Reusable Long constant for zero.

SHORT_MINUS_ONE

public static final Short SHORT_MINUS_ONE
Reusable Short constant for minus one.

SHORT_ONE

public static final Short SHORT_ONE
Reusable Short constant for one.

SHORT_ZERO

public static final Short SHORT_ZERO
Reusable Short constant for zero.

Constructor Details

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 Details

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

createBigDecimal

public static BigDecimal createBigDecimal(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

createBigInteger

public static BigInteger createBigInteger(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

createDouble

public static Double createDouble(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

createFloat

public static Float createFloat(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

createInteger

public static Integer createInteger(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

createLong

public static Long createLong(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

createNumber

public static Number createNumber(String str)
            throws 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

isDigits

public static boolean isDigits(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(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

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

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

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

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

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 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

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 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

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 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

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

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

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

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

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 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

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 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

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 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

stringToInt

public static int stringToInt(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

stringToInt

public static int stringToInt(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

toDouble

public static double toDouble(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(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

toFloat

public static float toFloat(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(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

toInt

public static int toInt(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

toInt

public static int toInt(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(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(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

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