/**
* Returns the number of documents in an index that a phrase occurs in.
* If it occurs in more than threshold documents then cut off search.
*
* @param string $phrase to look up in index
* @param int $threshold once count in posting list for any word
* reaches to threshold then return the number
* @param string $index_name selected index for search engine
* @param string $lang locale tag for the query
* @return int number of documents phrase occurs in
*/
static function numDocsIndex($phrase, $threshold, $index_name, $lang)
{
PhraseParser::canonicalizePunctuatedTerms($phrase, $lang);
$terms = PhraseParser::stemCharGramSegment($phrase, $lang);
$num = count($terms);
if ($index_name == NULL) {
return 0;
}
if (count($terms) > MAX_QUERY_TERMS) {
$terms = array_slice($terms, 0, MAX_QUERY_TERMS);
}
$whole_phrase = implode(" ", $terms);
return IndexManager::numDocsTerm($whole_phrase, $index_name, $threshold);
}
