org.apache.lucene.util.automaton

Class Automata

java.lang.Object

org.apache.lucene.util.automaton.Automata

public final class Automata
extends Object

Construction of basic automata.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Method Summary

Methods

Modifier and Type	Method and Description
static int	appendAnyChar(Automaton a, int state) Accept any single character starting from the specified state, returning the new state
static int	appendChar(Automaton a, int state, int c) Appends the specified character to the specified state, returning a new state.
static Automaton	makeAnyChar() Returns a new (deterministic) automaton that accepts any single codepoint.
static Automaton	makeAnyString() Returns a new (deterministic) automaton that accepts all strings.
static Automaton	makeChar(int c) Returns a new (deterministic) automaton that accepts a single codepoint of the given value.
static Automaton	makeCharRange(int min, int max) Returns a new (deterministic) automaton that accepts a single codepoint whose value is in the given interval (including both end points).
static Automaton	makeEmpty() Returns a new (deterministic) automaton with the empty language.
static Automaton	makeEmptyString() Returns a new (deterministic) automaton that accepts only the empty string.
static Automaton	makeInterval(int min, int max, int digits) Returns a new automaton that accepts strings representing decimal non-negative integers in the given interval.
static Automaton	makeString(int[] word, int offset, int length) Returns a new (deterministic) automaton that accepts the single given string from the specified unicode code points.
static Automaton	makeString(String s) Returns a new (deterministic) automaton that accepts the single given string.
static Automaton	makeStringUnion(Collection<BytesRef> utf8Strings) Returns a new (deterministic and minimal) automaton that accepts the union of the given collection of BytesRefs representing UTF-8 encoded strings.

Methods inherited from class java.lang.Object

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

Method Detail

makeEmpty

public static Automaton makeEmpty()

Returns a new (deterministic) automaton with the empty language.

makeEmptyString

public static Automaton makeEmptyString()

Returns a new (deterministic) automaton that accepts only the empty string.

makeAnyString

public static Automaton makeAnyString()

Returns a new (deterministic) automaton that accepts all strings.

makeAnyChar

public static Automaton makeAnyChar()

Returns a new (deterministic) automaton that accepts any single codepoint.

appendAnyChar

public static int appendAnyChar(Automaton a,
                int state)

Accept any single character starting from the specified state, returning the new state

makeChar

public static Automaton makeChar(int c)

Returns a new (deterministic) automaton that accepts a single codepoint of the given value.

appendChar

public static int appendChar(Automaton a,
             int state,
             int c)

Appends the specified character to the specified state, returning a new state.

makeCharRange

public static Automaton makeCharRange(int min,
                      int max)

Returns a new (deterministic) automaton that accepts a single codepoint whose value is in the given interval (including both end points).

makeInterval

public static Automaton makeInterval(int min,
                     int max,
                     int digits)
                              throws IllegalArgumentException

Returns a new automaton that accepts strings representing decimal non-negative integers in the given interval.

Parameters:

min - minimal value of interval

max - maximal value of interval (both end points are included in the interval)

digits - if >0, use fixed number of digits (strings must be prefixed by 0's to obtain the right length) - otherwise, the number of digits is not fixed (any number of leading 0s is accepted)

Throws:

IllegalArgumentException - if min>max or if numbers in the interval cannot be expressed with the given fixed number of digits

makeString

public static Automaton makeString(String s)

Returns a new (deterministic) automaton that accepts the single given string.

makeString

public static Automaton makeString(int[] word,
                   int offset,
                   int length)

Returns a new (deterministic) automaton that accepts the single given string from the specified unicode code points.

makeStringUnion

public static Automaton makeStringUnion(Collection<BytesRef> utf8Strings)

Returns a new (deterministic and minimal) automaton that accepts the union of the given collection of BytesRefs representing UTF-8 encoded strings.

Parameters:

utf8Strings - The input strings, UTF-8 encoded. The collection must be in sorted order.

Returns:

An Automaton accepting all input strings. The resulting automaton is codepoint based (full unicode codepoints on transitions).