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

    All Methods Static Methods Concrete 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` | `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` | `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` | `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` | `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 `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`

- - ### 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.

    - #### makeAnyBinary

          public static Automaton makeAnyBinary()

      Returns a new (deterministic) automaton that accepts all binary terms.

    - #### 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).

    - #### 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(Collection<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).

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