Class TermAutomatonQuery

  • All Implemented Interfaces:

    public class TermAutomatonQuery
    extends Query
    implements Accountable
    A proximity query that lets you express an automaton, whose transitions are terms, to match documents. This is a generalization of other proximity queries like PhraseQuery, MultiPhraseQuery and SpanNearQuery. It is likely slow, since it visits any document having any of the terms (i.e. it acts like a disjunction, not a conjunction like PhraseQuery), and then it must merge-sort all positions within each document to test whether/how many times the automaton matches.

    After creating the query, use createState(), setAccept(int, boolean), addTransition(int, int, java.lang.String) and addAnyTransition(int, int) to build up the automaton. Once you are done, call finish() and then execute the query.

    This code is very new and likely has exciting bugs!

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

      • TermAutomatonQuery

        public TermAutomatonQuery​(String field)
    • Method Detail

      • createState

        public int createState()
        Returns a new state; state 0 is always the initial state.
      • setAccept

        public void setAccept​(int state,
                              boolean accept)
        Marks the specified state as accept or not.
      • addTransition

        public void addTransition​(int source,
                                  int dest,
                                  String term)
        Adds a transition to the automaton.
      • addTransition

        public void addTransition​(int source,
                                  int dest,
                                  BytesRef term)
        Adds a transition to the automaton.
      • addAnyTransition

        public void addAnyTransition​(int source,
                                     int dest)
        Adds a transition matching any term.
      • finish

        public void finish()
        Call this once you are done adding states/transitions.
      • finish

        public void finish​(int determinizeWorkLimit)
        Call this once you are done adding states/transitions.
        determinizeWorkLimit - Maximum effort to spend determinizing the automaton. Higher numbers allow this operation to consume more memory but allow more complex automatons. Use Operations.DEFAULT_DETERMINIZE_WORK_LIMIT as a decent default if you don't otherwise know what to specify.
      • equals

        public boolean equals​(Object other)
        Returns true iff o is equal to this.
        Specified by:
        equals in class Query
      • hashCode

        public int hashCode()
        Specified by:
        hashCode in class Query
      • toDot

        public String toDot()
        Returns the dot (graphviz) representation of this automaton. This is extremely useful for visualizing the automaton.