NetricsServerInterface.NetricsCharmap Class Reference

Define a character map. More...

Public Member Functions
	NetricsCharmap (String name)
	Specify the name of the character map.
void	foldCase ()
	Equate all letter cases to lower case.
void	foldDiacritics ()
	Equate characters with diacritics with their normal cognates.
void	mapWhitespace (char c)
	Map all whitespace characters to a specific character.
void	mapPunctuation (char c)
	Map all punctuation characters to a specific character.
void	mapChars (char[] fromchars, char[] tochars)
	Use this method to equate any character with any other.
override String	ToString ()
	Returns a string representation of the character map.

Static Public Attributes
const String	Standard = "=STD="
	The name of the predefined default character map.
const String	Punctuation = "=PUNCT="
	The name of the predefined punctuation sensitive character map.

Detailed Description

Define a character map.

When matching data it is usually advantageous to perform certain character normalizations before matching. These include things such as mapping all letters to a common letter case, normalizing white space, stripping out certain special characters. A character map defines the set of rules to be applied. ibi™ Patterns - Search has a default character map that is appropriate for most cases. It maps all letters to lower case, strips all diacritic marks from letters, maps all punctuation and special characters to a blank, maps all whitespace to blanks, and compresses out all repeated blanks. There is also a second predefined character map that is similar to the standard map except that punctuation and special characters are left unchanged. For those cases where neither of these are appropriate the user can define their own character mapping rules. This class is the means by which these character mapping rules are defined.

Terms such as "letter" and "whitespace" are as defined in the unicode standard. The exception is that "punctuation" or "special characters" is a little broader than the unicode standard. Within the ASCII range this includes all characters that are not letters, digits or whitespace.

The first 16 bits of the full unicode character set are supported. This includes all commonly used code pages, including the Chinese and Japanese characters.

See also

NetricsServerInterface.cmapcreate

Constructor & Destructor Documentation

NetricsCharmap()

NetricsServerInterface.NetricsCharmap.NetricsCharmap ( String  name )

inline

Specify the name of the character map.

The name will be used when createing a table or thesaurus to tie a character map to a field. It must be unique among all currently defined character maps.

Parameters

name	Name of the character map.

Member Function Documentation

foldCase()

void NetricsServerInterface.NetricsCharmap.foldCase ( )

inline

Equate all letter cases to lower case.

This adds a rule that all letters should be mapped to a common letter case (lower case is used).

foldDiacritics()

void NetricsServerInterface.NetricsCharmap.foldDiacritics ( )

inline

Equate characters with diacritics with their normal cognates.

This adds a rule that strips all diacritic marks from letters.

mapChars()

void NetricsServerInterface.NetricsCharmap.mapChars ( char[]  fromchars, char[]  tochars  )

inline

Use this method to equate any character with any other.

A character at index x in the from array will be mapped to the character at index x in the to array. Each pair of characters will be considered equivalent for the purposes of matching.

Mappings defined here will supercede the character class mappings defined by foldCase, foldDiacritics, mapWhitespace and mapPunctuation. Thus if you wanted to map all punctuation marks except the pound (#) character you could do so by calling mapPunctuation and mapChars with the pound character mapped to itself.

Parameters

fromchars	The characters to map from
tochars	The characters to map to

mapPunctuation()

void NetricsServerInterface.NetricsCharmap.mapPunctuation ( char  c )

inline

Map all punctuation characters to a specific character.

This is often used to equate hyphen, slash, period, comma, etc to the space character. This ignores all punctuation and special characters except that they are considered token separators. If desired they can be mapped to a different character. In this case all punctuation and special characters would be considered equivalent, but they would not act as token separators.

Parameters

c	The character to map to

mapWhitespace()

void NetricsServerInterface.NetricsCharmap.mapWhitespace ( char  c )

inline

Map all whitespace characters to a specific character.

This adds a rule the maps all whitespace characters to a common character.

Note: mapping whitespace to any character other than the standard blank character will significantly alter the scoring of data as all data will be considered a single token.

Parameters

c	The character to map to

ToString()

override String NetricsServerInterface.NetricsCharmap.ToString ( )

inline

Returns a string representation of the character map.

Returns

a string representation of the character map.