org.apache.commons.lang

Class NumberUtils


public final class NumberUtils
extends Object

Provides extra functionality for Java Number classes.
Since:
1.0

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 val)
Convert a String to a BigDecimal.
static BigInteger
createBigInteger(String val)
Convert a String to a BigInteger.
static Double
createDouble(String val)
Convert a String to a Double.
static Float
createFloat(String val)
Convert a String to a Float.
static Integer
createInteger(String val)
Convert a String to a Integer, handling hex and octal notations.
static Long
createLong(String val)
Convert a String to a Long.
static Number
createNumber(String val)
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 int
maximum(int a, int b, int c)
Gets the maximum of three int values.
static long
maximum(long a, long b, long c)
Gets the maximum of three long values.
static int
minimum(int a, int b, int c)
Gets the minimum of three int values.
static long
minimum(long a, long b, long c)
Gets the minimum of three long values.
static int
stringToInt(String str)
Convert a String to an int, returning zero if the conversion fails.
static int
stringToInt(String str, int defaultValue)
Convert a String to an int, returning a default value if the conversion fails.

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

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 val)
Convert a String to a BigDecimal.
Parameters:
val - a String to convert
Returns:
converted BigDecimal
Throws:
NumberFormatException - if the value cannot be converted

createBigInteger

public static BigInteger createBigInteger(String val)
Convert a String to a BigInteger.
Parameters:
val - a String to convert
Returns:
converted BigInteger
Throws:
NumberFormatException - if the value cannot be converted

createDouble

public static Double createDouble(String val)
Convert a String to a Double.
Parameters:
val - a String to convert
Returns:
converted Double
Throws:
NumberFormatException - if the value cannot be converted

createFloat

public static Float createFloat(String val)
Convert a String to a Float.
Parameters:
val - a String to convert
Returns:
converted Float
Throws:
NumberFormatException - if the value cannot be converted

createInteger

public static Integer createInteger(String val)
Convert a String to a Integer, handling hex and octal notations.
Parameters:
val - a String to convert
Returns:
converted Integer
Throws:
NumberFormatException - if the value cannot be converted

createLong

public static Long createLong(String val)
Convert a String to a Long.
Parameters:
val - a String to convert
Returns:
converted Long
Throws:
NumberFormatException - if the value cannot be converted

createNumber

public static Number createNumber(String val)
            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 hold 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.

Parameters:
val - String containing a number
Returns:
Number created from the string
Throws:
NumberFormatException - if the value cannot be converted
Usages and Demos :

View More Examples of createNumber(String val)
   1: 
   2: import org.apache.commons.lang.NumberUtils;
   3: 
   4:         ...
   5:         try {
   6:             return NumberUtils.createNumber(str);
   7:         } catch (NumberFormatException nfe) {
   8:             System.err.println(nfe.getMessage());
   9:             return null;

View Full Code Here

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
Usages and Demos :

View More Examples of isNumber(String str)

maximum

public static int maximum(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

maximum

public static long maximum(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

minimum

public static int minimum(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

minimum

public static long minimum(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

stringToInt

public static int stringToInt(String str)
Convert a String to an int, returning zero if the conversion fails.
Parameters:
str - the string to convert
Returns:
the int represented by the string, or zero if conversion fails

stringToInt

public static int stringToInt(String str,
                              int defaultValue)
Convert a String to an int, returning a default value if the conversion fails.
Parameters:
str - the string to convert
defaultValue - the default value
Returns:
the int represented by the string, or the default if conversion fails