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API Documentation

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TermInfosReader.h

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/*------------------------------------------------------------------------------
* Copyright (C) 2003-2006 Ben van Klinken and the CLucene Team
* 
* Distributable under the terms of either the Apache License (Version 2.0) or 
* the GNU Lesser General Public License, as specified in the COPYING file.
------------------------------------------------------------------------------*/
#ifndef _lucene_index_TermInfosReader_
#define _lucene_index_TermInfosReader_

#if defined(_LUCENE_PRAGMA_ONCE)
# pragma once
#endif

#include "Terms.h"
#include "SegmentTermEnum.h"
#include "CLucene/store/Directory.h"
#include "CLucene/util/ThreadLocal.h"
#include "FieldInfos.h"
#include "TermInfo.h"
#include "TermInfosWriter.h"

CL_NS_DEF(index)
        class TermInfosReader :LUCENE_BASE{
        private:
                CL_NS(store)::Directory* directory;
                const char* segment;
                FieldInfos* fieldInfos;

                CL_NS(util)::ThreadLocal<SegmentTermEnum*, 
                        CL_NS(util)::Deletor::Object<SegmentTermEnum> > enumerators;

                SegmentTermEnum* getEnum();
                SegmentTermEnum* origEnum;
                SegmentTermEnum* indexEnum;
                int64_t _size;

                Term* indexTerms;
        int32_t indexTermsLength;
                TermInfo* indexInfos;
                int64_t* indexPointers;

                DEFINE_MUTEX(THIS_LOCK)

        public:
                //Constructor.
        //Reads the TermInfos file (.tis) and eventually the Term Info Index file (.tii)
                TermInfosReader(CL_NS(store)::Directory* dir, const char* segment, FieldInfos* fis);
                //Destructor
                ~TermInfosReader();
                //Close the enumeration of TermInfos
                void close();
                
                //Return the size of the enumeration of TermInfos
                int64_t size() const;

                int32_t getSkipInterval() { return origEnum->skipInterval; }
                
                // Returns an enumeration of terms starting at or after the named term. 
                // If no term is specified, an enumeration of all the Terms 
                // and TermInfos in the set is returned.
                SegmentTermEnum* terms(const Term* term=NULL);
                
                // Returns the TermInfo for a Term in the set
                // synchronized
                TermInfo* get(const Term* term);
        private:
                //Reads the term info index file or .tti file.
                void ensureIndexIsRead();

                // Returns the offset of the greatest index entry which is less than term.
                int32_t getIndexOffset(const Term* term);

                //Reposition the current Term and TermInfo to indexOffset
                void seekEnum(const int32_t indexOffset);  

                //Scans the Enumeration of terms for term and returns the corresponding TermInfo instance if found.
        //The search is started from the current term.
                TermInfo* scanEnum(const Term* term);

        //Scans the enumeration to the requested position and returns the
        //Term located at that position
                Term* scanEnum(const int32_t position);
                
                // Returns the position of a Term in the set
                // synchronized 
                int64_t getPosition(const Term* term);

                // Returns the nth term in the set. 
                // synchronized
                Term* get(const int32_t position);

        };
CL_NS_END
#endif

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