Beispiel #1
0
 /**
  * Re-write query into primitive queries in the context of specified index
  *
  * @param \Zend\Search\Lucene\SearchIndex $index
  * @throws \Zend\Search\Lucene\Exception\OutOfBoundsException
  * @return \Zend\Search\Lucene\Search\Query\AbstractQuery
  */
 public function rewrite(Lucene\SearchIndex $index)
 {
     $this->_matches = array();
     if ($this->_field === null) {
         // Search through all fields
         $fields = $index->getFieldNames(true);
     } else {
         $fields = array($this->_field);
     }
     $maxTerms = Lucene\Lucene::getTermsPerQueryLimit();
     foreach ($fields as $field) {
         $index->resetTermsStream();
         if ($this->_lowerTerm !== null) {
             $lowerTerm = new Index\Term($this->_lowerTerm->text, $field);
             $index->skipTo($lowerTerm);
             if (!$this->_inclusive && $index->currentTerm() == $lowerTerm) {
                 // Skip lower term
                 $index->nextTerm();
             }
         } else {
             $index->skipTo(new Index\Term('', $field));
         }
         if ($this->_upperTerm !== null) {
             // Walk up to the upper term
             $upperTerm = new Index\Term($this->_upperTerm->text, $field);
             while ($index->currentTerm() !== null && $index->currentTerm()->field == $field && $index->currentTerm()->text < $upperTerm->text) {
                 $this->_matches[] = $index->currentTerm();
                 if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
                     throw new OutOfBoundsException('Terms per query limit is reached.');
                 }
                 $index->nextTerm();
             }
             if ($this->_inclusive && $index->currentTerm() == $upperTerm) {
                 // Include upper term into result
                 $this->_matches[] = $upperTerm;
             }
         } else {
             // Walk up to the end of field data
             while ($index->currentTerm() !== null && $index->currentTerm()->field == $field) {
                 $this->_matches[] = $index->currentTerm();
                 if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
                     throw new OutOfBoundsException('Terms per query limit is reached.');
                 }
                 $index->nextTerm();
             }
         }
         $index->closeTermsStream();
     }
     if (count($this->_matches) == 0) {
         return new EmptyResult();
     } else {
         if (count($this->_matches) == 1) {
             return new Term(reset($this->_matches));
         } else {
             $rewrittenQuery = new MultiTerm();
             foreach ($this->_matches as $matchedTerm) {
                 $rewrittenQuery->addTerm($matchedTerm);
             }
             return $rewrittenQuery;
         }
     }
 }
Beispiel #2
0
 /**
  * Re-write query into primitive queries in the context of specified index
  *
  * @param \Zend\Search\Lucene\SearchIndex $index
  * @throws \Zend\Search\Lucene\Exception\RuntimeException
  * @throws \Zend\Search\Lucene\Exception\OutOfBoundsException
  * @return \Zend\Search\Lucene\Search\Query\AbstractQuery
  */
 public function rewrite(Lucene\SearchIndex $index)
 {
     $this->_matches = array();
     if ($this->_pattern->field === null) {
         // Search through all fields
         $fields = $index->getFieldNames(true);
     } else {
         $fields = array($this->_pattern->field);
     }
     $prefix = self::_getPrefix($this->_pattern->text);
     $prefixLength = strlen($prefix);
     $matchExpression = '/^' . str_replace(array('\\?', '\\*'), array('.', '.*'), preg_quote($this->_pattern->text, '/')) . '$/';
     if ($prefixLength < self::$_minPrefixLength) {
         throw new RuntimeException('At least ' . self::$_minPrefixLength . ' non-wildcard characters are required at the beginning of pattern.');
     }
     /** @todo check for PCRE unicode support may be performed through Zend_Environment in some future */
     if (@preg_match('/\\pL/u', 'a') == 1) {
         // PCRE unicode support is turned on
         // add Unicode modifier to the match expression
         $matchExpression .= 'u';
     }
     $maxTerms = Lucene\Lucene::getTermsPerQueryLimit();
     foreach ($fields as $field) {
         $index->resetTermsStream();
         if ($prefix != '') {
             $index->skipTo(new Index\Term($prefix, $field));
             while ($index->currentTerm() !== null && $index->currentTerm()->field == $field && substr($index->currentTerm()->text, 0, $prefixLength) == $prefix) {
                 if (preg_match($matchExpression, $index->currentTerm()->text) === 1) {
                     $this->_matches[] = $index->currentTerm();
                     if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
                         throw new OutOfBoundsException('Terms per query limit is reached.');
                     }
                 }
                 $index->nextTerm();
             }
         } else {
             $index->skipTo(new Index\Term('', $field));
             while ($index->currentTerm() !== null && $index->currentTerm()->field == $field) {
                 if (preg_match($matchExpression, $index->currentTerm()->text) === 1) {
                     $this->_matches[] = $index->currentTerm();
                     if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
                         throw new OutOfBoundsException('Terms per query limit is reached.');
                     }
                 }
                 $index->nextTerm();
             }
         }
         $index->closeTermsStream();
     }
     if (count($this->_matches) == 0) {
         return new EmptyResult();
     } else {
         if (count($this->_matches) == 1) {
             return new Term(reset($this->_matches));
         } else {
             $rewrittenQuery = new MultiTerm();
             foreach ($this->_matches as $matchedTerm) {
                 $rewrittenQuery->addTerm($matchedTerm);
             }
             return $rewrittenQuery;
         }
     }
 }
Beispiel #3
0
    /**
     * Re-write query into primitive queries in the context of specified index
     *
     * @param \Zend\Search\Lucene\SearchIndex $index
     * @throws \Zend\Search\Lucene\Exception\OutOfBoundsException
     * @return \Zend\Search\Lucene\Search\Query\AbstractQuery
     */
    public function rewrite(Lucene\SearchIndex $index)
    {
        $this->_matches  = array();
        $this->_scores   = array();
        $this->_termKeys = array();

        if ($this->_term->field === null) {
            // Search through all fields
            $fields = $index->getFieldNames(true /* indexed fields list */);
        } else {
            $fields = array($this->_term->field);
        }

        $prefix           = Index\Term::getPrefix($this->_term->text, $this->_prefixLength);
        $prefixByteLength = strlen($prefix);
        $prefixUtf8Length = Index\Term::getLength($prefix);

        $termLength       = Index\Term::getLength($this->_term->text);

        $termRest         = substr($this->_term->text, $prefixByteLength);
        // we calculate length of the rest in bytes since levenshtein() is not UTF-8 compatible
        $termRestLength   = strlen($termRest);

        $scaleFactor = 1/(1 - $this->_minimumSimilarity);

        $maxTerms = Lucene\Lucene::getTermsPerQueryLimit();
        foreach ($fields as $field) {
            $index->resetTermsStream();

            if ($prefix != '') {
                $index->skipTo(new Index\Term($prefix, $field));

                while ($index->currentTerm() !== null          &&
                       $index->currentTerm()->field == $field  &&
                       substr($index->currentTerm()->text, 0, $prefixByteLength) == $prefix) {
                    // Calculate similarity
                    $target = substr($index->currentTerm()->text, $prefixByteLength);

                    $maxDistance = isset($this->_maxDistances[strlen($target)])?
                                       $this->_maxDistances[strlen($target)] :
                                       $this->_calculateMaxDistance($prefixUtf8Length, $termRestLength, strlen($target));

                    if ($termRestLength == 0) {
                        // we don't have anything to compare.  That means if we just add
                        // the letters for current term we get the new word
                        $similarity = (($prefixUtf8Length == 0)? 0 : 1 - strlen($target)/$prefixUtf8Length);
                    } else if (strlen($target) == 0) {
                        $similarity = (($prefixUtf8Length == 0)? 0 : 1 - $termRestLength/$prefixUtf8Length);
                    } else if ($maxDistance < abs($termRestLength - strlen($target))){
                        //just adding the characters of term to target or vice-versa results in too many edits
                        //for example "pre" length is 3 and "prefixes" length is 8.  We can see that
                        //given this optimal circumstance, the edit distance cannot be less than 5.
                        //which is 8-3 or more precisesly abs(3-8).
                        //if our maximum edit distance is 4, then we can discard this word
                        //without looking at it.
                        $similarity = 0;
                    } else {
                        $similarity = 1 - levenshtein($termRest, $target)/($prefixUtf8Length + min($termRestLength, strlen($target)));
                    }

                    if ($similarity > $this->_minimumSimilarity) {
                        $this->_matches[]  = $index->currentTerm();
                        $this->_termKeys[] = $index->currentTerm()->key();
                        $this->_scores[]   = ($similarity - $this->_minimumSimilarity)*$scaleFactor;

                        if ($maxTerms != 0  &&  count($this->_matches) > $maxTerms) {
                            throw new OutOfBoundsException('Terms per query limit is reached.');
                        }
                    }

                    $index->nextTerm();
                }
            } else {
                $index->skipTo(new Index\Term('', $field));

                while ($index->currentTerm() !== null  &&  $index->currentTerm()->field == $field) {
                    // Calculate similarity
                    $target = $index->currentTerm()->text;

                    $maxDistance = isset($this->_maxDistances[strlen($target)])?
                                       $this->_maxDistances[strlen($target)] :
                                       $this->_calculateMaxDistance(0, $termRestLength, strlen($target));

                    if ($maxDistance < abs($termRestLength - strlen($target))){
                        //just adding the characters of term to target or vice-versa results in too many edits
                        //for example "pre" length is 3 and "prefixes" length is 8.  We can see that
                        //given this optimal circumstance, the edit distance cannot be less than 5.
                        //which is 8-3 or more precisesly abs(3-8).
                        //if our maximum edit distance is 4, then we can discard this word
                        //without looking at it.
                        $similarity = 0;
                    } else {
                        $similarity = 1 - levenshtein($termRest, $target)/min($termRestLength, strlen($target));
                    }

                    if ($similarity > $this->_minimumSimilarity) {
                        $this->_matches[]  = $index->currentTerm();
                        $this->_termKeys[] = $index->currentTerm()->key();
                        $this->_scores[]   = ($similarity - $this->_minimumSimilarity)*$scaleFactor;

                        if ($maxTerms != 0  &&  count($this->_matches) > $maxTerms) {
                            throw new OutOfBoundsException('Terms per query limit is reached.');
                        }
                    }

                    $index->nextTerm();
                }
            }

            $index->closeTermsStream();
        }

        if (count($this->_matches) == 0) {
            return new EmptyResult();
        } else if (count($this->_matches) == 1) {
            return new Term(reset($this->_matches));
        } else {
            $rewrittenQuery = new Boolean();

            array_multisort($this->_scores,   SORT_DESC, SORT_NUMERIC,
                            $this->_termKeys, SORT_ASC,  SORT_STRING,
                            $this->_matches);

            $termCount = 0;
            foreach ($this->_matches as $id => $matchedTerm) {
                $subquery = new Term($matchedTerm);
                $subquery->setBoost($this->_scores[$id]);

                $rewrittenQuery->addSubquery($subquery);

                $termCount++;
                if ($termCount >= self::MAX_CLAUSE_COUNT) {
                    break;
                }
            }

            return $rewrittenQuery;
        }
    }