lucene.php

很棒的在线教学系统

        $fdtFile->seek($fieldValuesPosition, SEEK_CUR);
        $fieldCount = $fdtFile->readVInt();

        $doc = new Zend_Search_Lucene_Document();
        for ($count = 0; $count < $fieldCount; $count++) {
            $fieldNum = $fdtFile->readVInt();
            $bits = $fdtFile->readByte();

            $fieldInfo = $segmentInfo->getField($fieldNum);

            if (!($bits & 2)) { // Text data
                $field = new Zend_Search_Lucene_Field($fieldInfo->name,
                                                      $fdtFile->readString(),
                                                      'UTF-8',
                                                      true,
                                                      $fieldInfo->isIndexed,
                                                      $bits & 1 );
            } else {            // Binary data
                $field = new Zend_Search_Lucene_Field($fieldInfo->name,
                                                      $fdtFile->readBinary(),
                                                      '',
                                                      true,
                                                      $fieldInfo->isIndexed,
                                                      $bits & 1,
                                                      true );
            }

            $doc->addField($field);
        }

        return $doc;
    }


    /**
     * Returns true if index contain documents with specified term.
     *
     * Is used for query optimization.
     *
     * @param Zend_Search_Lucene_Index_Term $term
     * @return boolean
     */
    public function hasTerm(Zend_Search_Lucene_Index_Term $term)
    {
        foreach ($this->_segmentInfos as $segInfo) {
            if ($segInfo->getTermInfo($term) instanceof Zend_Search_Lucene_Index_TermInfo) {
                return true;
            }
        }

        return false;
    }

    /**
     * Returns IDs of all the documents containing term.
     *
     * @param Zend_Search_Lucene_Index_Term $term
     * @return array
     */
    public function termDocs(Zend_Search_Lucene_Index_Term $term)
    {
        $result = array();
        $segmentStartDocId = 0;

        foreach ($this->_segmentInfos as $segInfo) {
            $termInfo = $segInfo->getTermInfo($term);

            if (!$termInfo instanceof Zend_Search_Lucene_Index_TermInfo) {
                $segmentStartDocId += $segInfo->count();
                continue;
            }

            $frqFile = $segInfo->openCompoundFile('.frq');
            $frqFile->seek($termInfo->freqPointer,SEEK_CUR);
            $docId = 0;
            for( $count=0; $count < $termInfo->docFreq; $count++ ) {
                $docDelta = $frqFile->readVInt();
                if( $docDelta % 2 == 1 ) {
                    $docId += ($docDelta-1)/2;
                } else {
                    $docId += $docDelta/2;
                    // read freq
                    $frqFile->readVInt();
                }

                $result[] = $segmentStartDocId + $docId;
            }

            $segmentStartDocId += $segInfo->count();
        }

        return $result;
    }


    /**
     * Returns an array of all term freqs.
     * Result array structure: array(docId => freq, ...)
     *
     * @param Zend_Search_Lucene_Index_Term $term
     * @return integer
     */
    public function termFreqs(Zend_Search_Lucene_Index_Term $term)
    {
        $result = array();
        $segmentStartDocId = 0;
        foreach ($this->_segmentInfos as $segmentInfo) {
            $result += $segmentInfo->termFreqs($term, $segmentStartDocId);

            $segmentStartDocId += $segmentInfo->count();
        }

        return $result;
    }

    /**
     * Returns an array of all term positions in the documents.
     * Result array structure: array(docId => array(pos1, pos2, ...), ...)
     *
     * @param Zend_Search_Lucene_Index_Term $term
     * @return array
     */
    public function termPositions(Zend_Search_Lucene_Index_Term $term)
    {
        $result = array();
        $segmentStartDocId = 0;
        foreach ($this->_segmentInfos as $segmentInfo) {
            $result += $segmentInfo->termPositions($term, $segmentStartDocId);

            $segmentStartDocId += $segmentInfo->count();
        }

        return $result;
    }


    /**
     * Returns the number of documents in this index containing the $term.
     *
     * @param Zend_Search_Lucene_Index_Term $term
     * @return integer
     */
    public function docFreq(Zend_Search_Lucene_Index_Term $term)
    {
        $result = 0;
        foreach ($this->_segmentInfos as $segInfo) {
            $termInfo = $segInfo->getTermInfo($term);
            if ($termInfo !== null) {
                $result += $termInfo->docFreq;
            }
        }

        return $result;
    }


    /**
     * Retrive similarity used by index reader
     *
     * @return Zend_Search_Lucene_Search_Similarity
     */
    public function getSimilarity()
    {
        return Zend_Search_Lucene_Search_Similarity::getDefault();
    }


    /**
     * Returns a normalization factor for "field, document" pair.
     *
     * @param integer $id
     * @param string $fieldName
     * @return float
     */
    public function norm($id, $fieldName)
    {
        if ($id >= $this->_docCount) {
            return null;
        }

        $segmentStartId = 0;
        foreach ($this->_segmentInfos as $segInfo) {
            if ($segmentStartId + $segInfo->count() > $id) {
                break;
            }

            $segmentStartId += $segInfo->count();
        }

        if ($segInfo->isDeleted($id - $segmentStartId)) {
            return 0;
        }

        return $segInfo->norm($id - $segmentStartId, $fieldName);
    }

    /**
     * Returns true if any documents have been deleted from this index.
     *
     * @return boolean
     */
    public function hasDeletions()
    {
        foreach ($this->_segmentInfos as $segmentInfo) {
            if ($segmentInfo->hasDeletions()) {
                return true;
            }
        }

        return false;
    }


    /**
     * Deletes a document from the index.
     * $id is an internal document id
     *
     * @param integer|Zend_Search_Lucene_Search_QueryHit $id
     * @throws Zend_Search_Lucene_Exception
     */
    public function delete($id)
    {
        if ($id instanceof Zend_Search_Lucene_Search_QueryHit) {
            /* @var $id Zend_Search_Lucene_Search_QueryHit */
            $id = $id->id;
        }

        if ($id >= $this->_docCount) {
            throw new Zend_Search_Lucene_Exception('Document id is out of the range.');
        }

        $segmentStartId = 0;
        foreach ($this->_segmentInfos as $segmentInfo) {
            if ($segmentStartId + $segmentInfo->count() > $id) {
                break;
            }

            $segmentStartId += $segmentInfo->count();
        }
        $segmentInfo->delete($id - $segmentStartId);

        $this->_hasChanges = true;
    }



    /**
     * Adds a document to this index.
     *
     * @param Zend_Search_Lucene_Document $document
     */
    public function addDocument(Zend_Search_Lucene_Document $document)
    {
        $this->getIndexWriter()->addDocument($document);
        $this->_docCount++;
        
        $this->_hasChanges = true;
    }


    /**
     * Update document counter
     */
    private function _updateDocCount()
    {
        $this->_docCount = 0;
        foreach ($this->_segmentInfos as $segInfo) {
            $this->_docCount += $segInfo->count();
        }
    }

    /**
     * Commit changes resulting from delete() or undeleteAll() operations.
     *
     * @todo undeleteAll processing.
     */
    public function commit()
    {
        if ($this->_hasChanges) {
            foreach ($this->_segmentInfos as $segInfo) {
                $segInfo->writeChanges();
            }
            
            $this->getIndexWriter()->commit();
            
            $this->_updateDocCount();
            
            $this->_hasChanges = false;
        }
    }


    /**
     * Optimize index.
     *
     * Merges all segments into one
     */
    public function optimize()
    {
        // Commit changes if any changes have been made
        $this->commit();

        if (count($this->_segmentInfos) > 1 || $this->hasDeletions()) {
            $this->getIndexWriter()->optimize();
            $this->_updateDocCount();
        }
    }


    /**
     * Returns an array of all terms in this index.
     *
     * @return array
     */
    public function terms()
    {
        $result = array();

        $segmentInfoQueue = new Zend_Search_Lucene_Index_SegmentInfoPriorityQueue();

        foreach ($this->_segmentInfos as $segmentInfo) {
            $segmentInfo->reset();

            // Skip "empty" segments
            if ($segmentInfo->currentTerm() !== null) {
                $segmentInfoQueue->put($segmentInfo);
            }
        }

        while (($segmentInfo = $segmentInfoQueue->pop()) !== null) {
            if ($segmentInfoQueue->top() === null ||
                $segmentInfoQueue->top()->currentTerm()->key() !=
                            $segmentInfo->currentTerm()->key()) {
                // We got new term
                $result[] = $segmentInfo->currentTerm();
            }

            if ($segmentInfo->nextTerm() !== null) {
                // Put segment back into the priority queue
                $segmentInfoQueue->put($segmentInfo);
            }
        }

        return $result;
    }


    /**
     * Terms stream queue
     *
     * @var Zend_Search_Lucene_Index_SegmentInfoPriorityQueue
     */
    private $_termsStreamQueue = null;

    /**
     * Last Term in a terms stream
     *
     * @var Zend_Search_Lucene_Index_Term
     */
    private $_lastTerm = null;

    /**
     * Reset terms stream.
     */
    public function resetTermsStream()
    {
        $this->_termsStreamQueue = new Zend_Search_Lucene_Index_SegmentInfoPriorityQueue();

        foreach ($this->_segmentInfos as $segmentInfo) {
            $segmentInfo->reset();

            // Skip "empty" segments
            if ($segmentInfo->currentTerm() !== null) {
                $this->_termsStreamQueue->put($segmentInfo);
            }
        }

        $this->nextTerm();
    }

    /**
     * Skip terms stream up to specified term preffix.
     *
     * Prefix contains fully specified field info and portion of searched term
     *
     * @param Zend_Search_Lucene_Index_Term $prefix
     */
    public function skipTo(Zend_Search_Lucene_Index_Term $prefix)
    {
        $segments = array();

        while (($segmentInfo = $this->_termsStreamQueue->pop()) !== null) {
            $segments[] = $segmentInfo;
        }

        foreach ($segments as $segmentInfo) {
            $segmentInfo->skipTo($prefix);

            if ($segmentInfo->currentTerm() !== null) {
                $this->_termsStreamQueue->put($segmentInfo);
            }
        }

        $this->nextTerm();
    }

    /**
     * Scans terms dictionary and returns next term
     *
     * @return Zend_Search_Lucene_Index_Term|null
     */
    public function nextTerm()
    {
        while (($segmentInfo = $this->_termsStreamQueue->pop()) !== null) {
            if ($this->_termsStreamQueue->top() === null ||
                $this->_termsStreamQueue->top()->currentTerm()->key() !=
                            $segmentInfo->currentTerm()->key()) {
                // We got new term
                $this->_lastTerm = $segmentInfo->currentTerm();

                if ($segmentInfo->nextTerm() !== null) {
                    // Put segment back into the priority queue
                    $this->_termsStreamQueue->put($segmentInfo);
                }

                return $this->_lastTerm;
            }

            if ($segmentInfo->nextTerm() !== null) {
                // Put segment back into the priority queue
                $this->_termsStreamQueue->put($segmentInfo);
            }
        }

        // End of stream
        $this->_lastTerm = null;

        return null;
    }

    /**
     * Returns term in current position
     *
     * @return Zend_Search_Lucene_Index_Term|null
     */
    public function currentTerm()
    {
        return $this->_lastTerm;
    }

    /**
     * Close terms stream
     *
     * Should be used for resources clean up if stream is not read up to the end
     */
    public function closeTermsStream()
    {
        while (($segmentInfo = $this->_termsStreamQueue->pop()) !== null) {
            $segmentInfo->closeTermsStream();
        }

        $this->_termsStreamQueue = null;
        $this->_lastTerm         = null;
    }


    /*************************************************************************
    @todo UNIMPLEMENTED
    *************************************************************************/
    /**
     * Undeletes all documents currently marked as deleted in this index.
     *
     * @todo Implementation
     */
    public function undeleteAll()
    {}
}