multiterm.php

来自「PHP 知识管理系统（基于树结构的知识管理系统）, 英文原版的PHP源码。」· PHP 代码 · 共 585 行 · 第 1/2 页

     *
     * @param Zend_Search_Lucene $reader
     * @return Zend_Search_Lucene_Search_Weight
     */
    public function createWeight($reader)
    {
        $this->_weight = new Zend_Search_Lucene_Search_Weight_MultiTerm($this, $reader);
        return $this->_weight;
    }


    /**
     * Calculate result vector for Conjunction query
     * (like '+something +another')
     *
     * @param Zend_Search_Lucene $reader
     */
    private function _calculateConjunctionResult($reader)
    {
        $this->_resVector = null;

        if (count($this->_terms) == 0) {
            $this->_resVector = array();
        }

        foreach( $this->_terms as $termId=>$term ) {
            if($this->_resVector === null) {
                $this->_resVector = array_flip($reader->termDocs($term));
            } else {
                $this->_resVector = array_intersect_key($this->_resVector, array_flip($reader->termDocs($term)));
            }

            if (count($this->_resVector) == 0) {
                // Empty result set, we don't need to check other terms
                break;
            }

            $this->_termsPositions[$termId] = $reader->termPositions($term);
        }

        ksort($this->_resVector, SORT_NUMERIC);
    }


    /**
     * Calculate result vector for non Conjunction query
     * (like '+something -another')
     *
     * @param Zend_Search_Lucene $reader
     */
    private function _calculateNonConjunctionResult($reader)
    {
        $required   = null;
        $optional   = array();
        $prohibited = array();

        foreach ($this->_terms as $termId => $term) {
            $termDocs = array_flip($reader->termDocs($term));

            if ($this->_signs[$termId] === true) {
                // required
                if ($required !== null) {
                    // array intersection
                    $required = array_intersect_key($required, $termDocs);
                } else {
                    $required = $termDocs;
                }
            } elseif ($this->_signs[$termId] === false) {
                // prohibited
                // array union
                $prohibited += $termDocs;
            } else {
                // neither required, nor prohibited
                // array union
                $optional += $termDocs;
            }

            $this->_termsPositions[$termId] = $reader->termPositions($term);
        }

        if ($required !== null) {
            $this->_resVector = array_diff_key($required, $prohibited);
        } else {
            $this->_resVector = array_diff_key($optional, $prohibited);
        }

        ksort($this->_resVector, SORT_NUMERIC);
    }


    /**
     * Score calculator for conjunction queries (all terms are required)
     *
     * @param integer $docId
     * @param Zend_Search_Lucene $reader
     * @return float
     */
    public function _conjunctionScore($docId, $reader)
    {
        if ($this->_coord === null) {
            $this->_coord = $reader->getSimilarity()->coord(count($this->_terms),
                                                            count($this->_terms) );
        }

        $score = 0.0;

        foreach ($this->_terms as $termId=>$term) {
            $score += $reader->getSimilarity()->tf(count($this->_termsPositions[$termId][$docId]) ) *
                      $this->_weights[$termId]->getValue() *
                      $reader->norm($docId, $term->field);
        }

        return $score * $this->_coord * $this->getBoost();
    }


    /**
     * Score calculator for non conjunction queries (not all terms are required)
     *
     * @param integer $docId
     * @param Zend_Search_Lucene $reader
     * @return float
     */
    public function _nonConjunctionScore($docId, $reader)
    {
        if ($this->_coord === null) {
            $this->_coord = array();

            $maxCoord = 0;
            foreach ($this->_signs as $sign) {
                if ($sign !== false /* not prohibited */) {
                    $maxCoord++;
                }
            }

            for ($count = 0; $count <= $maxCoord; $count++) {
                $this->_coord[$count] = $reader->getSimilarity()->coord($count, $maxCoord);
            }
        }

        $score = 0.0;
        $matchedTerms = 0;
        foreach ($this->_terms as $termId=>$term) {
            // Check if term is
            if ($this->_signs[$termId] !== false &&            // not prohibited
                isset($this->_termsPositions[$termId][$docId]) // matched
               ) {
                $matchedTerms++;
                $score +=
                      $reader->getSimilarity()->tf(count($this->_termsPositions[$termId][$docId]) ) *
                      $this->_weights[$termId]->getValue() *
                      $reader->norm($docId, $term->field);
            }
        }

        return $score * $this->_coord[$matchedTerms] * $this->getBoost();
    }

    /**
     * Execute query in context of index reader
     * It also initializes necessary internal structures
     *
     * @param Zend_Search_Lucene $reader
     */
    public function execute($reader)
    {
        if ($this->_signs === null) {
            $this->_calculateConjunctionResult($reader);
        } else {
            $this->_calculateNonConjunctionResult($reader);
        }

        // 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 $reader
     * @return float
     */
    public function score($docId, $reader)
    {
        if (isset($this->_resVector[$docId])) {
            if ($this->_signs === null) {
                return $this->_conjunctionScore($docId, $reader);
            } else {
                return $this->_nonConjunctionScore($docId, $reader);
            }
        } else {
            return 0;
        }
    }

    /**
     * Return query terms
     *
     * @return array
     */
    public function getQueryTerms()
    {
        if ($this->_signs === null) {
            return $this->_terms;
        }

        $terms = array();

        foreach ($this->_signs as $id => $sign) {
            if ($sign !== false) {
                $terms[] = $this->_terms[$id];
            }
        }

        return $terms;
    }

    /**
     * Highlight query terms
     *
     * @param integer &$colorIndex
     * @param Zend_Search_Lucene_Document_Html $doc
     */
    public function highlightMatchesDOM(Zend_Search_Lucene_Document_Html $doc, &$colorIndex)
    {
        $words = array();

        if ($this->_signs === null) {
            foreach ($this->_terms as $term) {
                $words[] = $term->text;
            }
        } else {
            foreach ($this->_signs as $id => $sign) {
                if ($sign !== false) {
                    $words[] = $this->_terms[$id]->text;
                }
            }
        }

        $doc->highlight($words, $this->_getHighlightColor($colorIndex));
    }

    /**
     * Print a query
     *
     * @return string
     */
    public function __toString()
    {
        // It's used only for query visualisation, so we don't care about characters escaping

        $query = '';

        foreach ($this->_terms as $id => $term) {
            if ($id != 0) {
                $query .= ' ';
            }

            if ($this->_signs === null || $this->_signs[$id] === true) {
                $query .= '+';
            } else if ($this->_signs[$id] === false) {
                $query .= '-';
            }

            if ($term->field !== null) {
                $query .= $term->field . ':';
            }
            $query .= $term->text;
        }

        if ($this->getBoost() != 1) {
            $query = '(' . $query . ')^' . $this->getBoost();
        }

        return $query;
    }
}