jrexx is a powerful easy-to-use regular expression
API for textual pattern matching. Technically jrexx
uses a minimized deterministic FSA (finite state
automaton) and compiles the textual representation
of the regular expression into such an automaton.
Besides the usual pattern matching functionality,
jrexx provides an introspection API for exploration
of the automaton's structure by 'states' and
'transitions'. Since the automaton is deterministic
and minimized the pattern matching alogorithm is
extremly fast (compared to the java regular
expression API in JDK1.4) and works with huge
patterns and input texts. Since FSA can be handled
as sets, jrexx also offers all basic set operations
for complement, union, intersection and difference,
which is not provided by other regex implementations
(as far as we know).