Package org.apache.lucene.sandbox.search

Class TermAutomatonQuery

java.lang.Object
org.apache.lucene.search.Query
org.apache.lucene.sandbox.search.TermAutomatonQuery
All Implemented Interfaces:
Accountable
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 Details

    • TermAutomatonQuery

      public TermAutomatonQuery(String field)

  • Method Details

    • 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.
      Parameters:
      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.

    • createWeight

      public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException
      Overrides:
      createWeight in class Query
      Throws:
      IOException

    • toString

      public String toString(String field)
      Specified by:
      toString in class Query

    • 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

    • ramBytesUsed

      public long ramBytesUsed()
      Specified by:
      ramBytesUsed in interface Accountable

    • toDot

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

    • rewrite

      public Query rewrite(IndexReader reader) throws IOException
      Overrides:
      rewrite in class Query
      Throws:
      IOException

    • visit

      public void visit(QueryVisitor visitor)
      Specified by:
      visit in class Query