Package 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.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final int`
  `MAX_STRING_UNION_TERM_LENGTH`
  `makeStringUnion(Iterable)` limits terms of this max length to ensure the stack doesn't overflow while building, since our algorithm currently relies on recursion.

- ## Method Summary

  Modifier and Type
  Method
  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`
  `makeAnyBinary()`
  Returns a new (deterministic) automaton that accepts all binary terms.
  `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`
  `makeBinary(BytesRef term)`
  Returns a new (deterministic) automaton that accepts the single given binary term.
  `static Automaton`
  `makeBinaryInterval(BytesRef min, boolean minInclusive, BytesRef max, boolean maxInclusive)`
  Creates a new deterministic, minimal automaton accepting all binary terms in the specified interval.
  `static Automaton`
  `makeBinaryStringUnion(Iterable<BytesRef> utf8Strings)`
  Returns a new (deterministic and minimal) automaton that accepts the union of the given collection of `BytesRef`s representing UTF-8 encoded strings.
  `static Automaton`
  `makeBinaryStringUnion(BytesRefIterator utf8Strings)`
  Returns a new (deterministic and minimal) automaton that accepts the union of the given iterator of `BytesRef`s representing UTF-8 encoded strings.
  `static Automaton`
  `makeChar(int c)`
  Returns a new (deterministic) automaton that accepts a single codepoint of the given value.
  `static Automaton`
  `makeCharClass(int[] starts, int[] ends)`
  Returns a new minimal automaton that accepts any of the codepoint ranges
  `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`
  `makeCharSet(int[] codepoints)`
  Returns a new minimal automaton that accepts any of the provided codepoints
  `static Automaton`
  `makeDecimalInterval(int min, int max, int digits)`
  Returns a new automaton that accepts strings representing decimal (base 10) non-negative integers in the given interval.
  `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`
  `makeNonEmptyBinary()`
  Returns a new (deterministic) automaton that accepts all binary terms except the empty string.
  `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(Iterable<BytesRef> utf8Strings)`
  Returns a new (deterministic and minimal) automaton that accepts the union of the given collection of `BytesRef`s representing UTF-8 encoded strings.
  `static Automaton`
  `makeStringUnion(BytesRefIterator utf8Strings)`
  Returns a new (deterministic and minimal) automaton that accepts the union of the given iterator of `BytesRef`s representing UTF-8 encoded strings.

  ### Methods inherited from class java.lang.Object

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

- ## Field Details

  - ### MAX_STRING_UNION_TERM_LENGTH

    public static final int MAX_STRING_UNION_TERM_LENGTH
    `makeStringUnion(Iterable)` limits terms of this max length to ensure the stack doesn't overflow while building, since our algorithm currently relies on recursion.
    See Also:
      - Constant Field Values

- ## Method Details

  - ### 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.

  - ### makeAnyBinary

    public static Automaton makeAnyBinary()
    Returns a new (deterministic) automaton that accepts all binary terms.

  - ### makeNonEmptyBinary

    public static Automaton makeNonEmptyBinary()
    Returns a new (deterministic) automaton that accepts all binary terms except the empty string.

  - ### 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).

  - ### makeCharSet

    public static Automaton makeCharSet(int[] codepoints)
    Returns a new minimal automaton that accepts any of the provided codepoints

  - ### makeCharClass

    public static Automaton makeCharClass(int[] starts, int[] ends)
    Returns a new minimal automaton that accepts any of the codepoint ranges

  - ### makeBinaryInterval

    public static Automaton makeBinaryInterval(BytesRef min, boolean minInclusive, BytesRef max, boolean maxInclusive)
    Creates a new deterministic, minimal automaton accepting all binary terms in the specified interval. Note that unlike `makeDecimalInterval(int, int, int)`, the returned automaton is infinite, because terms behave like floating point numbers leading with a decimal point. However, in the special case where min == max, and both are inclusive, the automata will be finite and accept exactly one term.

  - ### makeDecimalInterval

    public static Automaton makeDecimalInterval(int min, int max, int digits) throws IllegalArgumentException
    Returns a new automaton that accepts strings representing decimal (base 10) 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.

  - ### makeBinary

    public static Automaton makeBinary(BytesRef term)
    Returns a new (deterministic) automaton that accepts the single given binary term.

  - ### 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(Iterable<BytesRef> utf8Strings)
    Returns a new (deterministic and minimal) automaton that accepts the union of the given collection of `BytesRef`s 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).

  - ### makeBinaryStringUnion

    public static Automaton makeBinaryStringUnion(Iterable<BytesRef> utf8Strings)
    Returns a new (deterministic and minimal) automaton that accepts the union of the given collection of `BytesRef`s representing UTF-8 encoded strings. The resulting automaton will be built in a binary representation.
    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 binary based (UTF-8 encoded byte transition labels).

  - ### makeStringUnion

    public static Automaton makeStringUnion(BytesRefIterator utf8Strings) throws IOException
    Returns a new (deterministic and minimal) automaton that accepts the union of the given iterator of `BytesRef`s representing UTF-8 encoded strings.
    Parameters:
      `utf8Strings` - The input strings, UTF-8 encoded. The iterator must be in sorted order.
    Returns:
      An `Automaton` accepting all input strings. The resulting automaton is codepoint based (full unicode codepoints on transitions).
    Throws:
      `IOException`

  - ### makeBinaryStringUnion

    public static Automaton makeBinaryStringUnion(BytesRefIterator utf8Strings) throws IOException
    Returns a new (deterministic and minimal) automaton that accepts the union of the given iterator of `BytesRef`s representing UTF-8 encoded strings. The resulting automaton will be built in a binary representation.
    Parameters:
      `utf8Strings` - The input strings, UTF-8 encoded. The iterator must be in sorted order.
    Returns:
      An `Automaton` accepting all input strings. The resulting automaton is binary based (UTF-8 encoded byte transition labels).
    Throws:
      `IOException`