com.cobber.fta

Class RegExpGenerator

java.lang.Object

com.cobber.fta.RegExpGenerator

public class RegExpGenerator
extends java.lang.Object

Analyze a set of strings and return a suitable Regular Expression. Unlikely to be an optimal Regular Expression!!

Typical usage is:

 
 		RegExpGenerator generator = new RegExpGenerator();

 		generator.train("janv.");
 		generator.train("oct");
 		generator.train("dec.");
 		...

 		String result = generator.getResult();
 
 

Constructor Summary

Constructors

Constructor and Description
RegExpGenerator()
RegExpGenerator(boolean asSet, int maxSetSize, java.util.Locale locale)

Method Summary

Modifier and Type	Method and Description
java.lang.String	getResult() Given the set of Strings trained() return a Regular Expression which will accept any of the training set.
java.util.Set<java.lang.String>	getValues() Get the set of Strings (in upper case) used to train the Generator.
static boolean	isSpecial(char ch) Is the supplied character reserved a special meaning in Regular Expressions? Note: We do not declare '-' as a special character, so should not be used in a Character Class
static java.lang.String	merge(java.lang.String firstRE, java.lang.String secondRE)
static java.lang.String	slosh(char ch)
static java.lang.String	slosh(java.lang.String input) Return an escaped String (similar to Pattern.quote but not unconditional).
static java.lang.String	smash(java.lang.String input) Fast method to simplify a string so that we can determine if all inputs are of the same form.
static java.lang.String	smashedAsRegExp(java.lang.String smashed) Generate a Regular Expression from the 'smashed' input.
void	train(java.lang.String input) This method should be called for each string in the set.

Methods inherited from class java.lang.Object

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

Constructor Detail

RegExpGenerator

public RegExpGenerator()

RegExpGenerator

public RegExpGenerator(boolean asSet,
                       int maxSetSize,
                       java.util.Locale locale)

Method Detail

isSpecial

public static boolean isSpecial(char ch)

Is the supplied character reserved a special meaning in Regular Expressions? Note: We do not declare '-' as a special character, so should not be used in a Character Class

Parameters:

ch - The character to test.

Returns:

True if the character is reserved.

slosh

public static java.lang.String slosh(char ch)

merge

public static java.lang.String merge(java.lang.String firstRE,
                                     java.lang.String secondRE)

slosh

public static java.lang.String slosh(java.lang.String input)

Return an escaped String (similar to Pattern.quote but not unconditional).

Parameters:

input - The String to be protected.

Returns:

An escaped String.

smash

public static java.lang.String smash(java.lang.String input)

Fast method to simplify a string so that we can determine if all inputs are of the same form. Smashed strings follow the following rules: - Strings of length greater than 30 are replaced with .+ - any digit is replaced with '9' - any alpha is replaced with 'X' - any % is sloshed (i.e. replaced with %%)

Parameters:

input - The input String to be smashed.

Returns:

A 'smashed' String.

smashedAsRegExp

public static java.lang.String smashedAsRegExp(java.lang.String smashed)

Generate a Regular Expression from the 'smashed' input.

Parameters:

smashed - The smashed input

Returns:

A Regular Expression that captures the 'smashed' input.

train

public void train(java.lang.String input)

This method should be called for each string in the set.

Parameters:

input - The String to be used as part of the set.

getResult

public java.lang.String getResult()

Given the set of Strings trained() return a Regular Expression which will accept any of the training set.

Returns:

A regular expression matching the training set.

getValues

public java.util.Set<java.lang.String> getValues()

Get the set of Strings (in upper case) used to train the Generator.

Returns:

The set of Strings (in upper case).