org.apache.lucene.util.automaton
Class AutomatonTestUtil

java.lang.Object
  org.apache.lucene.util.automaton.AutomatonTestUtil

public class AutomatonTestUtil
extends Object

Utilities for testing automata.

Capable of generating random regular expressions, and automata, and also provides a number of very basic unoptimized implementations (*slow) for testing.

Nested Class Summary

static class

AutomatonTestUtil.RandomAcceptedStrings Lets you retrieve random strings accepted by an Automaton.

Constructor Summary

AutomatonTestUtil()

Method Summary

static void	assertNoDetachedStates(Automaton a) Checks that an automaton has no detached states that are unreachable from the initial state.
static void	determinizeSimple(Automaton a) Simple, original brics implementation of determinize()
static void	determinizeSimple(Automaton a, Set<State> initialset) Simple, original brics implementation of determinize() Determinizes the given automaton using the given set of initial states.
static boolean	isFiniteSlow(Automaton a) Returns true if the language of this automaton is finite.
static void	minimizeSimple(Automaton a) Simple, original brics implementation of Brzozowski minimize()
static Automaton	randomAutomaton(Random random) return a random NFA/DFA for testing
static String	randomRegexp(Random r) Returns random string, including full unicode range.

Methods inherited from class java.lang.Object

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

Constructor Detail

AutomatonTestUtil

public AutomatonTestUtil()

Method Detail

randomRegexp

public static String randomRegexp(Random r)

Returns random string, including full unicode range.

randomAutomaton

public static Automaton randomAutomaton(Random random)

return a random NFA/DFA for testing

minimizeSimple

public static void minimizeSimple(Automaton a)

Simple, original brics implementation of Brzozowski minimize()

determinizeSimple

public static void determinizeSimple(Automaton a)

Simple, original brics implementation of determinize()

determinizeSimple

public static void determinizeSimple(Automaton a,
                                     Set<State> initialset)

Simple, original brics implementation of determinize() Determinizes the given automaton using the given set of initial states.

isFiniteSlow

public static boolean isFiniteSlow(Automaton a)

Returns true if the language of this automaton is finite.

WARNING: this method is slow, it will blow up if the automaton is large. this is only used to test the correctness of our faster implementation.

assertNoDetachedStates

public static void assertNoDetachedStates(Automaton a)

Checks that an automaton has no detached states that are unreachable from the initial state.