net.sf.kdgcommons.lang

Class NumberUtil

java.lang.Object

net.sf.kdgcommons.lang.NumberUtil

public class NumberUtil
extends Object

A collection of static methods for working with subclasses of Number.

Constructor Summary

Constructors

Constructor and Description
NumberUtil()

Method Summary

Modifier and Type	Method and Description
static <T extends Number> T	dynamicCast(Object obj, Class<T> klass) Attempts to convert the first argument (which must be a subclass of Number) into an instance of the second (which must be a primitive wrapper type).
static Number	parse(String str, Class<? extends Number> klass) Parses the passed string into an instance of the specified class.
static String	toHexString(long value, int digits) Returns a hexadecimal string representing the passed value, padded as necessary to the specified number of digits.

Methods inherited from class java.lang.Object

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

Constructor Detail

NumberUtil

public NumberUtil()

Method Detail

parse

public static Number parse(String str,
                           Class<? extends Number> klass)

Parses the passed string into an instance of the specified class. Typically used when converting strings for bean fields.

Throws:

NumberFormatException - if the passed string cannot be parsed by the specified class.

toHexString

public static String toHexString(long value,
                                 int digits)

Returns a hexadecimal string representing the passed value, padded as necessary to the specified number of digits. Padding uses zero for positive numbers, "F" for negative numbers. For most uses, this is nicer than the unpadded format of Integer.toHexString().

Example: toHex(17, 4) returns "0011", while toHex(-17, 4) returns "FFEF".

Hex digits are uppercase; call toLowerCase() on the returned string if you don't like that.

The returned value can have as many digits as you like -- you're not limited to the 16 digits that a long can hold.

dynamicCast

public static <T extends Number> T dynamicCast(Object obj,
                                               Class<T> klass)

Attempts to convert the first argument (which must be a subclass of Number) into an instance of the second (which must be a primitive wrapper type). If passed null, will return null. If passed an instance of the desired type, will return it unchanged.

Throws:

ClassCastException - if the first argument is not a subclass of Number, or the second is not a supported type.