Class SpecialOperations

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

public final class SpecialOperations extends Object
Special automata operations.
  • Method Details

    • isFinite

      public static boolean isFinite(Automaton a)
      Returns true if the language of this automaton is finite.
    • getCommonPrefix

      public static String getCommonPrefix(Automaton a)
      Returns the longest string that is a prefix of all accepted strings and visits each state at most once.
      Returns:
      common prefix
    • getCommonPrefixBytesRef

      public static BytesRef getCommonPrefixBytesRef(Automaton a)
    • getCommonSuffix

      public static String getCommonSuffix(Automaton a)
      Returns the longest string that is a suffix of all accepted strings and visits each state at most once.
      Returns:
      common suffix
    • getCommonSuffixBytesRef

      public static BytesRef getCommonSuffixBytesRef(Automaton a)
    • reverse

      public static Set<State> reverse(Automaton a)
      Reverses the language of the given (non-singleton) automaton while returning the set of new initial states.
    • getFiniteStrings

      public static Set<IntsRef> getFiniteStrings(Automaton a, int limit)
      Returns the set of accepted strings, assuming that at most limit strings are accepted. If more than limit strings are accepted, the first limit strings found are returned. If limit<0, then the limit is infinite.