Viewing file:  Phrase.php (17.84 KB) -rw-rw-rw-
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
<?php
/**
* Zend Framework
*
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately.
*
* @category Zend
* @package Zend_Search_Lucene
* @subpackage Search
* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: Phrase.php 18954 2009-11-12 20:01:33Z alexander $
*/
/** Zend_Search_Lucene_Search_Query */
require_once 'Zend/Search/Lucene/Search/Query.php';
/**
* A Query that matches documents containing a particular sequence of terms.
*
* @category Zend
* @package Zend_Search_Lucene
* @subpackage Search
* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
class Zend_Search_Lucene_Search_Query_Phrase extends Zend_Search_Lucene_Search_Query
{
/**
* Terms to find.
* Array of Zend_Search_Lucene_Index_Term objects.
*
* @var array
*/
private $_terms;
/**
* Term positions (relative positions of terms within the phrase).
* Array of integers
*
* @var array
*/
private $_offsets;
/**
* Sets the number of other words permitted between words in query phrase.
* If zero, then this is an exact phrase search. For larger values this works
* like a WITHIN or NEAR operator.
*
* The slop is in fact an edit-distance, where the units correspond to
* moves of terms in the query phrase out of position. For example, to switch
* the order of two words requires two moves (the first move places the words
* atop one another), so to permit re-orderings of phrases, the slop must be
* at least two.
* More exact matches are scored higher than sloppier matches, thus search
* results are sorted by exactness.
*
* The slop is zero by default, requiring exact matches.
*
* @var integer
*/
private $_slop;
/**
* Result vector.
*
* @var array
*/
private $_resVector = null;
/**
* Terms positions vectors.
* Array of Arrays:
* term1Id => (docId => array( pos1, pos2, ... ), ...)
* term2Id => (docId => array( pos1, pos2, ... ), ...)
*
* @var array
*/
private $_termsPositions = array();
/**
* Class constructor. Create a new prase query.
*
* @param string $field Field to search.
* @param array $terms Terms to search Array of strings.
* @param array $offsets Relative term positions. Array of integers.
* @throws Zend_Search_Lucene_Exception
*/
public function __construct($terms = null, $offsets = null, $field = null)
{
$this->_slop = 0;
if (is_array($terms)) {
$this->_terms = array();
require_once 'Zend/Search/Lucene/Index/Term.php';
foreach ($terms as $termId => $termText) {
$this->_terms[$termId] = ($field !== null)? new Zend_Search_Lucene_Index_Term($termText, $field):
new Zend_Search_Lucene_Index_Term($termText);
}
} else if ($terms === null) {
$this->_terms = array();
} else {
require_once 'Zend/Search/Lucene/Exception.php';
throw new Zend_Search_Lucene_Exception('terms argument must be array of strings or null');
}
if (is_array($offsets)) {
if (count($this->_terms) != count($offsets)) {
require_once 'Zend/Search/Lucene/Exception.php';
throw new Zend_Search_Lucene_Exception('terms and offsets arguments must have the same size.');
}
$this->_offsets = $offsets;
} else if ($offsets === null) {
$this->_offsets = array();
foreach ($this->_terms as $termId => $term) {
$position = count($this->_offsets);
$this->_offsets[$termId] = $position;
}
} else {
require_once 'Zend/Search/Lucene/Exception.php';
throw new Zend_Search_Lucene_Exception('offsets argument must be array of strings or null');
}
}
/**
* Set slop
*
* @param integer $slop
*/
public function setSlop($slop)
{
$this->_slop = $slop;
}
/**
* Get slop
*
* @return integer
*/
public function getSlop()
{
return $this->_slop;
}
/**
* Adds a term to the end of the query phrase.
* The relative position of the term is specified explicitly or the one immediately
* after the last term added.
*
* @param Zend_Search_Lucene_Index_Term $term
* @param integer $position
*/
public function addTerm(Zend_Search_Lucene_Index_Term $term, $position = null) {
if ((count($this->_terms) != 0)&&(end($this->_terms)->field != $term->field)) {
require_once 'Zend/Search/Lucene/Exception.php';
throw new Zend_Search_Lucene_Exception('All phrase terms must be in the same field: ' .
$term->field . ':' . $term->text);
}
$this->_terms[] = $term;
if ($position !== null) {
$this->_offsets[] = $position;
} else if (count($this->_offsets) != 0) {
$this->_offsets[] = end($this->_offsets) + 1;
} else {
$this->_offsets[] = 0;
}
}
/**
* Re-write query into primitive queries in the context of specified index
*
* @param Zend_Search_Lucene_Interface $index
* @return Zend_Search_Lucene_Search_Query
*/
public function rewrite(Zend_Search_Lucene_Interface $index)
{
if (count($this->_terms) == 0) {
require_once 'Zend/Search/Lucene/Search/Query/Empty.php';
return new Zend_Search_Lucene_Search_Query_Empty();
} else if ($this->_terms[0]->field !== null) {
return $this;
} else {
require_once 'Zend/Search/Lucene/Search/Query/Boolean.php';
$query = new Zend_Search_Lucene_Search_Query_Boolean();
$query->setBoost($this->getBoost());
foreach ($index->getFieldNames(true) as $fieldName) {
$subquery = new Zend_Search_Lucene_Search_Query_Phrase();
$subquery->setSlop($this->getSlop());
require_once 'Zend/Search/Lucene/Index/Term.php';
foreach ($this->_terms as $termId => $term) {
$qualifiedTerm = new Zend_Search_Lucene_Index_Term($term->text, $fieldName);
$subquery->addTerm($qualifiedTerm, $this->_offsets[$termId]);
}
$query->addSubquery($subquery);
}
return $query;
}
}
/**
* Optimize query in the context of specified index
*
* @param Zend_Search_Lucene_Interface $index
* @return Zend_Search_Lucene_Search_Query
*/
public function optimize(Zend_Search_Lucene_Interface $index)
{
// Check, that index contains all phrase terms
foreach ($this->_terms as $term) {
if (!$index->hasTerm($term)) {
require_once 'Zend/Search/Lucene/Search/Query/Empty.php';
return new Zend_Search_Lucene_Search_Query_Empty();
}
}
if (count($this->_terms) == 1) {
// It's one term query
require_once 'Zend/Search/Lucene/Search/Query/Term.php';
$optimizedQuery = new Zend_Search_Lucene_Search_Query_Term(reset($this->_terms));
$optimizedQuery->setBoost($this->getBoost());
return $optimizedQuery;
}
if (count($this->_terms) == 0) {
require_once 'Zend/Search/Lucene/Search/Query/Empty.php';
return new Zend_Search_Lucene_Search_Query_Empty();
}
return $this;
}
/**
* Returns query term
*
* @return array
*/
public function getTerms()
{
return $this->_terms;
}
/**
* Set weight for specified term
*
* @param integer $num
* @param Zend_Search_Lucene_Search_Weight_Term $weight
*/
public function setWeight($num, $weight)
{
$this->_weights[$num] = $weight;
}
/**
* Constructs an appropriate Weight implementation for this query.
*
* @param Zend_Search_Lucene_Interface $reader
* @return Zend_Search_Lucene_Search_Weight
*/
public function createWeight(Zend_Search_Lucene_Interface $reader)
{
require_once 'Zend/Search/Lucene/Search/Weight/Phrase.php';
$this->_weight = new Zend_Search_Lucene_Search_Weight_Phrase($this, $reader);
return $this->_weight;
}
/**
* Score calculator for exact phrase queries (terms sequence is fixed)
*
* @param integer $docId
* @return float
*/
public function _exactPhraseFreq($docId)
{
$freq = 0;
// Term Id with lowest cardinality
$lowCardTermId = null;
// Calculate $lowCardTermId
foreach ($this->_terms as $termId => $term) {
if ($lowCardTermId === null ||
count($this->_termsPositions[$termId][$docId]) <
count($this->_termsPositions[$lowCardTermId][$docId]) ) {
$lowCardTermId = $termId;
}
}
// Walk through positions of the term with lowest cardinality
foreach ($this->_termsPositions[$lowCardTermId][$docId] as $lowCardPos) {
// We expect phrase to be found
$freq++;
// Walk through other terms
foreach ($this->_terms as $termId => $term) {
if ($termId != $lowCardTermId) {
$expectedPosition = $lowCardPos +
($this->_offsets[$termId] -
$this->_offsets[$lowCardTermId]);
if (!in_array($expectedPosition, $this->_termsPositions[$termId][$docId])) {
$freq--; // Phrase wasn't found.
break;
}
}
}
}
return $freq;
}
/**
* Score calculator for sloppy phrase queries (terms sequence is fixed)
*
* @param integer $docId
* @param Zend_Search_Lucene_Interface $reader
* @return float
*/
public function _sloppyPhraseFreq($docId, Zend_Search_Lucene_Interface $reader)
{
$freq = 0;
$phraseQueue = array();
$phraseQueue[0] = array(); // empty phrase
$lastTerm = null;
// Walk through the terms to create phrases.
foreach ($this->_terms as $termId => $term) {
$queueSize = count($phraseQueue);
$firstPass = true;
// Walk through the term positions.
// Each term position produces a set of phrases.
foreach ($this->_termsPositions[$termId][$docId] as $termPosition ) {
if ($firstPass) {
for ($count = 0; $count < $queueSize; $count++) {
$phraseQueue[$count][$termId] = $termPosition;
}
} else {
for ($count = 0; $count < $queueSize; $count++) {
if ($lastTerm !== null &&
abs( $termPosition - $phraseQueue[$count][$lastTerm] -
($this->_offsets[$termId] - $this->_offsets[$lastTerm])) > $this->_slop) {
continue;
}
$newPhraseId = count($phraseQueue);
$phraseQueue[$newPhraseId] = $phraseQueue[$count];
$phraseQueue[$newPhraseId][$termId] = $termPosition;
}
}
$firstPass = false;
}
$lastTerm = $termId;
}
foreach ($phraseQueue as $phrasePos) {
$minDistance = null;
for ($shift = -$this->_slop; $shift <= $this->_slop; $shift++) {
$distance = 0;
$start = reset($phrasePos) - reset($this->_offsets) + $shift;
foreach ($this->_terms as $termId => $term) {
$distance += abs($phrasePos[$termId] - $this->_offsets[$termId] - $start);
if($distance > $this->_slop) {
break;
}
}
if ($minDistance === null || $distance < $minDistance) {
$minDistance = $distance;
}
}
if ($minDistance <= $this->_slop) {
$freq += $reader->getSimilarity()->sloppyFreq($minDistance);
}
}
return $freq;
}
/**
* Execute query in context of index reader
* It also initializes necessary internal structures
*
* @param Zend_Search_Lucene_Interface $reader
* @param Zend_Search_Lucene_Index_DocsFilter|null $docsFilter
*/
public function execute(Zend_Search_Lucene_Interface $reader, $docsFilter = null)
{
$this->_resVector = null;
if (count($this->_terms) == 0) {
$this->_resVector = array();
}
$resVectors = array();
$resVectorsSizes = array();
$resVectorsIds = array(); // is used to prevent arrays comparison
foreach ($this->_terms as $termId => $term) {
$resVectors[] = array_flip($reader->termDocs($term));
$resVectorsSizes[] = count(end($resVectors));
$resVectorsIds[] = $termId;
$this->_termsPositions[$termId] = $reader->termPositions($term);
}
// sort resvectors in order of subquery cardinality increasing
array_multisort($resVectorsSizes, SORT_ASC, SORT_NUMERIC,
$resVectorsIds, SORT_ASC, SORT_NUMERIC,
$resVectors);
foreach ($resVectors as $nextResVector) {
if($this->_resVector === null) {
$this->_resVector = $nextResVector;
} else {
//$this->_resVector = array_intersect_key($this->_resVector, $nextResVector);
/**
* This code is used as workaround for array_intersect_key() slowness problem.
*/
$updatedVector = array();
foreach ($this->_resVector as $id => $value) {
if (isset($nextResVector[$id])) {
$updatedVector[$id] = $value;
}
}
$this->_resVector = $updatedVector;
}
if (count($this->_resVector) == 0) {
// Empty result set, we don't need to check other terms
break;
}
}
// ksort($this->_resVector, SORT_NUMERIC);
// Docs are returned ordered. Used algorithm doesn't change elements order.
// 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->_resVector;
}
/**
* Score specified document
*
* @param integer $docId
* @param Zend_Search_Lucene_Interface $reader
* @return float
*/
public function score($docId, Zend_Search_Lucene_Interface $reader)
{
if (isset($this->_resVector[$docId])) {
if ($this->_slop == 0) {
$freq = $this->_exactPhraseFreq($docId);
} else {
$freq = $this->_sloppyPhraseFreq($docId, $reader);
}
if ($freq != 0) {
$tf = $reader->getSimilarity()->tf($freq);
$weight = $this->_weight->getValue();
$norm = $reader->norm($docId, reset($this->_terms)->field);
return $tf * $weight * $norm * $this->getBoost();
}
// Included in result, but culculated freq is zero
return 0;
} else {
return 0;
}
}
/**
* Return query terms
*
* @return array
*/
public function getQueryTerms()
{
return $this->_terms;
}
/**
* Query specific matches highlighting
*
* @param Zend_Search_Lucene_Search_Highlighter_Interface $highlighter Highlighter object (also contains doc for highlighting)
*/
protected function _highlightMatches(Zend_Search_Lucene_Search_Highlighter_Interface $highlighter)
{
$words = array();
foreach ($this->_terms as $term) {
$words[] = $term->text;
}
$highlighter->highlight($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 (isset($this->_terms[0]) && $this->_terms[0]->field !== null) {
$query = $this->_terms[0]->field . ':';
} else {
$query = '';
}
$query .= '"';
foreach ($this->_terms as $id => $term) {
if ($id != 0) {
$query .= ' ';
}
$query .= $term->text;
}
$query .= '"';
if ($this->_slop != 0) {
$query .= '~' . $this->_slop;
}
if ($this->getBoost() != 1) {
$query .= '^' . round($this->getBoost(), 4);
}
return $query;
}
}
|