Java Code Examples for org.apache.lucene.util.automaton.Automata#makeEmpty()

The following examples show how to use org.apache.lucene.util.automaton.Automata#makeEmpty() . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source File: RegexCompletionQuery.java    From lucene-solr with Apache License 2.0 5 votes vote down vote up 
@Override
public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException {
  // If an empty regex is provided, we return an automaton that matches nothing. This ensures
  // consistency with PrefixCompletionQuery, which returns no results for an empty term.
  Automaton automaton = getTerm().text().isEmpty()
      ? Automata.makeEmpty()
      : new RegExp(getTerm().text(), flags).toAutomaton(maxDeterminizedStates);
  return new CompletionWeight(this, automaton);
}
Example 2
Source File: TestAutomatonQuery.java    From lucene-solr with Apache License 2.0 5 votes vote down vote up 
/**
 * Test handling of the empty language
 */
public void testEmptyOptimization() throws IOException {
  AutomatonQuery aq = new AutomatonQuery(newTerm("bogus"), Automata.makeEmpty());
  // not yet available: assertTrue(aq.getEnum(searcher.getIndexReader())
  // instanceof EmptyTermEnum);
  Terms terms = MultiTerms.getTerms(searcher.getIndexReader(), FN);
  assertSame(TermsEnum.EMPTY, aq.getTermsEnum(terms));
  assertEquals(0, automatonQueryNrHits(aq));
}
Example 3
Source File: XContentMapValues.java    From crate with Apache License 2.0 5 votes vote down vote up 
/**
 * Returns a function that filters a document map based on the given include and exclude rules.
 * @see #filter(Map, String[], String[]) for details
 */
public static Function<Map<String, ?>, Map<String, Object>> filter(String[] includes, String[] excludes) {
    CharacterRunAutomaton matchAllAutomaton = new CharacterRunAutomaton(Automata.makeAnyString());

    CharacterRunAutomaton include;
    if (includes == null || includes.length == 0) {
        include = matchAllAutomaton;
    } else {
        Automaton includeA = Regex.simpleMatchToAutomaton(includes);
        includeA = makeMatchDotsInFieldNames(includeA);
        include = new CharacterRunAutomaton(includeA);
    }

    Automaton excludeA;
    if (excludes == null || excludes.length == 0) {
        excludeA = Automata.makeEmpty();
    } else {
        excludeA = Regex.simpleMatchToAutomaton(excludes);
        excludeA = makeMatchDotsInFieldNames(excludeA);
    }
    CharacterRunAutomaton exclude = new CharacterRunAutomaton(excludeA);

    // NOTE: We cannot use Operations.minus because of the special case that
    // we want all sub properties to match as soon as an object matches

    return (map) -> filter(map,
        include, 0,
        exclude, 0,
        matchAllAutomaton);
}