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<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @link http://github.com/zendframework/zf2 for the canonical source repository
* @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @package Zend_Search
*/
namespace ZendSearch\Lucene\Search\Query\Preprocessing;
use ZendSearch\Lucene;
use ZendSearch\Lucene\Analysis\Analyzer;
use ZendSearch\Lucene\Index;
use ZendSearch\Lucene\Search\Exception\QueryParserException;
use ZendSearch\Lucene\Search\Highlighter\HighlighterInterface as Highlighter;
use ZendSearch\Lucene\Search\Query;
use Zend\Stdlib\ErrorHandler;
/**
* It's an internal abstract class intended to finalize ase a query processing after query parsing.
* This type of query is not actually involved into query execution.
*
* @category Zend
* @package Zend_Search_Lucene
* @subpackage Search
* @internal
*/
class Term extends AbstractPreprocessing
{
/**
* word (query parser lexeme) to find.
*
* @var string
*/
private $_word;
/**
* Word encoding (field name is always provided using UTF-8 encoding since it may be retrieved from index).
*
* @var string
*/
private $_encoding;
/**
* Field name.
*
* @var string
*/
private $_field;
/**
* Class constructor. Create a new preprocessing object for prase query.
*
* @param string $word Non-tokenized word (query parser lexeme) to search.
* @param string $encoding Word encoding.
* @param string $fieldName Field name.
*/
public function __construct($word, $encoding, $fieldName)
{
$this->_word = $word;
$this->_encoding = $encoding;
$this->_field = $fieldName;
}
/**
* Re-write query into primitive queries in the context of specified index
*
* @param \ZendSearch\Lucene\SearchIndexInterface $index
* @throws \ZendSearch\Lucene\Search\Exception\QueryParserException
* @return \ZendSearch\Lucene\Search\Query\AbstractQuery
*/
public function rewrite(Lucene\SearchIndexInterface $index)
{
if ($this->_field === null) {
$query = new Query\MultiTerm();
$query->setBoost($this->getBoost());
$hasInsignificantSubqueries = false;
if (Lucene\Lucene::getDefaultSearchField() === null) {
$searchFields = $index->getFieldNames(true);
} else {
$searchFields = array(Lucene\Lucene::getDefaultSearchField());
}
foreach ($searchFields as $fieldName) {
$subquery = new Term($this->_word,
$this->_encoding,
$fieldName);
$rewrittenSubquery = $subquery->rewrite($index);
foreach ($rewrittenSubquery->getQueryTerms() as $term) {
$query->addTerm($term);
}
if ($rewrittenSubquery instanceof Query\Insignificant) {
$hasInsignificantSubqueries = true;
}
}
if (count($query->getTerms()) == 0) {
$this->_matches = array();
if ($hasInsignificantSubqueries) {
return new Query\Insignificant();
} else {
return new Query\EmptyResult();
}
}
$this->_matches = $query->getQueryTerms();
return $query;
}
// -------------------------------------
// Recognize exact term matching (it corresponds to Keyword fields stored in the index)
// encoding is not used since we expect binary matching
$term = new Index\Term($this->_word, $this->_field);
if ($index->hasTerm($term)) {
$query = new Query\Term($term);
$query->setBoost($this->getBoost());
$this->_matches = $query->getQueryTerms();
return $query;
}
// -------------------------------------
// Recognize wildcard queries
/**
* @todo check for PCRE unicode support may be performed through Zend_Environment in some future
*/
ErrorHandler::start(E_WARNING);
$result = preg_match('/\pL/u', 'a');
ErrorHandler::stop();
if ($result == 1) {
$word = iconv($this->_encoding, 'UTF-8', $this->_word);
$wildcardsPattern = '/[*?]/u';
$subPatternsEncoding = 'UTF-8';
} else {
$word = $this->_word;
$wildcardsPattern = '/[*?]/';
$subPatternsEncoding = $this->_encoding;
}
$subPatterns = preg_split($wildcardsPattern, $word, -1, PREG_SPLIT_OFFSET_CAPTURE);
if (count($subPatterns) > 1) {
// Wildcard query is recognized
$pattern = '';
foreach ($subPatterns as $id => $subPattern) {
// Append corresponding wildcard character to the pattern before each sub-pattern (except first)
if ($id != 0) {
$pattern .= $word[ $subPattern[1] - 1 ];
}
// Check if each subputtern is a single word in terms of current analyzer
$tokens = Analyzer\Analyzer::getDefault()->tokenize($subPattern[0], $subPatternsEncoding);
if (count($tokens) > 1) {
throw new QueryParserException('Wildcard search is supported only for non-multiple word terms');
}
foreach ($tokens as $token) {
$pattern .= $token->getTermText();
}
}
$term = new Index\Term($pattern, $this->_field);
$query = new Query\Wildcard($term);
$query->setBoost($this->getBoost());
// Get rewritten query. Important! It also fills terms matching container.
$rewrittenQuery = $query->rewrite($index);
$this->_matches = $query->getQueryTerms();
return $rewrittenQuery;
}
// -------------------------------------
// Recognize one-term multi-term and "insignificant" queries
$tokens = Analyzer\Analyzer::getDefault()->tokenize($this->_word, $this->_encoding);
if (count($tokens) == 0) {
$this->_matches = array();
return new Query\Insignificant();
}
if (count($tokens) == 1) {
$term = new Index\Term($tokens[0]->getTermText(), $this->_field);
$query = new Query\Term($term);
$query->setBoost($this->getBoost());
$this->_matches = $query->getQueryTerms();
return $query;
}
//It's not insignificant or one term query
$query = new Query\MultiTerm();
/**
* @todo Process $token->getPositionIncrement() to support stemming, synonyms and other
* analizer design features
*/
foreach ($tokens as $token) {
$term = new Index\Term($token->getTermText(), $this->_field);
$query->addTerm($term, true); // all subterms are required
}
$query->setBoost($this->getBoost());
$this->_matches = $query->getQueryTerms();
return $query;
}
/**
* Query specific matches highlighting
*
* @param Highlighter $highlighter Highlighter object (also contains doc for highlighting)
*/
protected function _highlightMatches(Highlighter $highlighter)
{
/** Skip fields detection. We don't need it, since we expect all fields presented in the HTML body and don't differentiate them */
/** Skip exact term matching recognition, keyword fields highlighting is not supported */
// -------------------------------------
// Recognize wildcard queries
/**
* @todo check for PCRE unicode support may be performed through Zend_Environment in some future
*/
ErrorHandler::start(E_WARNING);
$result = preg_match('/\pL/u', 'a');
ErrorHandler::stop();
if ($result == 1) {
$word = iconv($this->_encoding, 'UTF-8', $this->_word);
$wildcardsPattern = '/[*?]/u';
$subPatternsEncoding = 'UTF-8';
} else {
$word = $this->_word;
$wildcardsPattern = '/[*?]/';
$subPatternsEncoding = $this->_encoding;
}
$subPatterns = preg_split($wildcardsPattern, $word, -1, PREG_SPLIT_OFFSET_CAPTURE);
if (count($subPatterns) > 1) {
// Wildcard query is recognized
$pattern = '';
foreach ($subPatterns as $id => $subPattern) {
// Append corresponding wildcard character to the pattern before each sub-pattern (except first)
if ($id != 0) {
$pattern .= $word[ $subPattern[1] - 1 ];
}
// Check if each subputtern is a single word in terms of current analyzer
$tokens = Analyzer\Analyzer::getDefault()->tokenize($subPattern[0], $subPatternsEncoding);
if (count($tokens) > 1) {
// Do nothing (nothing is highlighted)
return;
}
foreach ($tokens as $token) {
$pattern .= $token->getTermText();
}
}
$term = new Index\Term($pattern, $this->_field);
$query = new Query\Wildcard($term);
$query->_highlightMatches($highlighter);
return;
}
// -------------------------------------
// Recognize one-term multi-term and "insignificant" queries
$tokens = Analyzer\Analyzer::getDefault()->tokenize($this->_word, $this->_encoding);
if (count($tokens) == 0) {
// Do nothing
return;
}
if (count($tokens) == 1) {
$highlighter->highlight($tokens[0]->getTermText());
return;
}
//It's not insignificant or one term query
$words = array();
foreach ($tokens as $token) {
$words[] = $token->getTermText();
}
$highlighter->highlight($words);
}
/**
* Print a query
*
* @return string
*/
public function __toString()
{
// It's used only for query visualisation, so we don't care about characters escaping
if ($this->_field !== null) {
$query = $this->_field . ':';
} else {
$query = '';
}
$query .= $this->_word;
if ($this->getBoost() != 1) {
$query .= '^' . round($this->getBoost(), 4);
}
return $query;
}
}