A Java library for generating String from a regular expression.
Latest commit ccc32b5 Dec 21, 2016 @mifmif committed on GitHub Update README.md



A Java library for generating String that match a given regular expression. it help you generate all Strings that matches a given Regex, random one , or one String from the matched String based on it's index. Generex is based on the library http://www.brics.dk/~amoeller/automaton/.

Build Status

Features :

-Generate Random String that match the Regex.

-Specify the min/max length of the random generated String.

-Generate a list of all Strings that matches the Regex, if the number of String that matches the Regex is greater then Integer.MAX_VALUE , the returned list will contains Strings up to the size limit of java.util.List which is Integer.MAX_VALUE (see iterator's feature in this case).

-generate a sublist of the Strings that matches the Regex based on the lexicographical order.

-Given an index 'n' , generate the n'th element in lexicographical order of the list of Strings that matches the Regex.

-Prepare an iterator that loop over all the Strings that matches the Regex. even if the set of String that matches the given Regex is infinite.

How to use it :

If you use Maven you can include this library to your project by adding the following dependency:


The list of all available versions can be found at Maven Central.

Here is the sample Java code demonstrating library usage:

		Generex generex = new Generex("[0-3]([a-c]|[e-g]{1,2})");

		// Generate random String
		String randomStr = generex.random();
		System.out.println(randomStr);// a random value from the previous String list

		// generate the second String in lexicographical order that match the given Regex.
		String secondString = generex.getMatchedString(2);
		System.out.println(secondString);// it print '0b'

		// Generate all String that matches the given Regex.
		List<String> matchedStrs = generex.getAllMatchedStrings();

		// Using Generex iterator
		Iterator iterator = generex.iterator();
		while (iterator.hasNext()) {
			System.out.print(iterator.next() + " ");
		// it prints:
		// 0a 0b 0c 0e 0ee 0ef 0eg 0f 0fe 0ff 0fg 0g 0ge 0gf 0gg
		// 1a 1b 1c 1e 1ee 1ef 1eg 1f 1fe 1ff 1fg 1g 1ge 1gf 1gg
		// 2a 2b 2c 2e 2ee 2ef 2eg 2f 2fe 2ff 2fg 2g 2ge 2gf 2gg
		// 3a 3b 3c 3e 3ee 3ef 3eg 3f 3fe 3ff 3fg 3g 3ge 3gf 3gg


Generex is licensed under the Apache License, Version 2.0.