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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;
use ZendSearch\Lucene;
use ZendSearch\Lucene\Index;
use ZendSearch\Lucene\Search\Highlighter\HighlighterInterface as Highlighter;
use ZendSearch\Lucene\Search\Weight;
/**
* @category Zend
* @package Zend_Search_Lucene
* @subpackage Search
*/
class Term extends AbstractQuery
{
/**
* Term to find.
*
* @var \ZendSearch\Lucene\Index\Term
*/
private $_term;
/**
* Documents vector.
*
* @var array
*/
private $_docVector = null;
/**
* Term freqs vector.
* array(docId => freq, ...)
*
* @var array
*/
private $_termFreqs;
/**
* Zend_Search_Lucene_Search_Query_Term constructor
*
* @param \ZendSearch\Lucene\Index\Term $term
* @param boolean $sign
*/
public function __construct(Index\Term $term)
{
$this->_term = $term;
}
/**
* Re-write query into primitive queries in the context of specified index
*
* @param \ZendSearch\Lucene\SearchIndexInterface $index
* @return \ZendSearch\Lucene\Search\Query\AbstractQuery
*/
public function rewrite(Lucene\SearchIndexInterface $index)
{
if ($this->_term->field != null) {
return $this;
} else {
$query = new MultiTerm();
$query->setBoost($this->getBoost());
foreach ($index->getFieldNames(true) as $fieldName) {
$term = new Index\Term($this->_term->text, $fieldName);
$query->addTerm($term);
}
return $query->rewrite($index);
}
}
/**
* Optimize query in the context of specified index
*
* @param \ZendSearch\Lucene\SearchIndexInterface $index
* @return \ZendSearch\Lucene\Search\Query\AbstractQuery
*/
public function optimize(Lucene\SearchIndexInterface $index)
{
// Check, that index contains specified term
if (!$index->hasTerm($this->_term)) {
return new EmptyResult();
}
return $this;
}
/**
* Constructs an appropriate Weight implementation for this query.
*
* @param \ZendSearch\Lucene\SearchIndexInterface $reader
* @return \ZendSearch\Lucene\Search\Weight\Term
*/
public function createWeight(Lucene\SearchIndexInterface $reader)
{
$this->_weight = new Weight\Term($this->_term, $this, $reader);
return $this->_weight;
}
/**
* Execute query in context of index reader
* It also initializes necessary internal structures
*
* @param \ZendSearch\Lucene\SearchIndexInterface $reader
* @param \ZendSearch\Lucene\Index\DocsFilter|null $docsFilter
*/
public function execute(Lucene\SearchIndexInterface $reader, $docsFilter = null)
{
$this->_docVector = array_flip($reader->termDocs($this->_term, $docsFilter));
$this->_termFreqs = $reader->termFreqs($this->_term, $docsFilter);
// Initialize weight if it's not done yet
$this->_initWeight($reader);
}
/**
* Get document ids likely matching the query
*
* It's an array with document ids as keys (performance considerations)
*
* @return array
*/
public function matchedDocs()
{
return $this->_docVector;
}
/**
* Score specified document
*
* @param integer $docId
* @param \ZendSearch\Lucene\SearchIndexInterface $reader
* @return float
*/
public function score($docId, Lucene\SearchIndexInterface $reader)
{
if (isset($this->_docVector[$docId])) {
return $reader->getSimilarity()->tf($this->_termFreqs[$docId]) *
$this->_weight->getValue() *
$reader->norm($docId, $this->_term->field) *
$this->getBoost();
} else {
return 0;
}
}
/**
* Return query terms
*
* @return array
*/
public function getQueryTerms()
{
return array($this->_term);
}
/**
* Return query term
*
* @return \ZendSearch\Lucene\Index\Term
*/
public function getTerm()
{
return $this->_term;
}
/**
* Query specific matches highlighting
*
* @param Highlighter $highlighter Highlighter object (also contains doc for highlighting)
*/
protected function _highlightMatches(Highlighter $highlighter)
{
$highlighter->highlight($this->_term->text);
}
/**
* 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->_term->field !== null) {
$query = $this->_term->field . ':';
} else {
$query = '';
}
$query .= $this->_term->text;
if ($this->getBoost() != 1) {
$query = $query . '^' . round($this->getBoost(), 4);
}
return $query;
}
}