The document portion names each document containing the term. Documents are indicated by number. The frequency portion gives the number of times the term occurred in each document.
The pairs are ordered by document number. @see IndexReader#termDocs() */ class CLUCENE_EXPORT TermDocs { public: virtual ~TermDocs(); // Sets this to the data for a term. // The enumeration is reset to the start of the data for this term. virtual void seek(Term* term)=0; /** Sets this to the data for the current term in a {@link TermEnum}. * This may be optimized in some implementations. */ virtual void seek(TermEnum* termEnum)=0; // Returns the current document number.
This is invalid until {@link // #next()} is called for the first time. virtual int32_t doc() const=0; // Returns the frequency of the term within the current document.
This // is invalid until {@link #next()} is called for the first time. virtual int32_t freq() const=0; // Moves to the next pair in the enumeration.
Returns true iff there is // such a next pair in the enumeration. virtual bool next() =0; // Attempts to read multiple entries from the enumeration, up to length of // docs. Document numbers are stored in docs, and term // frequencies are stored in freqs. The freqs array must be as // int64_t as the docs array. // //
Returns the number of entries read. Zero is only returned when the // stream has been exhausted. virtual int32_t read(int32_t* docs, int32_t* freqs, int32_t length)=0; // Skips entries to the first beyond the current whose document number is // greater than or equal to target.
Returns true iff there is such // an entry.
Behaves as if written:
// bool skipTo(int32_t target) {
// do {
// if (!next())
// return false;
// } while (target > doc());
// return true;
// }
//
// Some implementations are considerably more efficient than that.
virtual bool skipTo(const int32_t target)=0;
// Frees associated resources.
virtual void close() = 0;
/** Solve the diamond inheritence problem by providing a reinterpret function.
* No dynamic casting is required and no RTTI data is needed to do this
*/
virtual TermPositions* __asTermPositions()=0;
};
/** Abstract class for enumerating terms.
Term enumerations are always ordered by Term.compareTo(). Each term in the enumeration is greater than all that precede it. */ class CLUCENE_EXPORT TermEnum: LUCENE_BASE, public CL_NS(util)::NamedObject { public: /** Increments the enumeration to the next element. True if one exists.*/ virtual bool next()=0; /** * Returns the current Term in the enumeration. * @param pointer if true, then increment the reference count before returning */ virtual Term* term(bool pointer=true)=0; /** Returns the docFreq of the current Term in the enumeration.*/ virtual int32_t docFreq() const=0; /** Closes the enumeration to further activity, freeing resources. */ virtual void close() =0; virtual ~TermEnum(); // Term Vector support /** Skips terms to the first beyond the current whose value is * greater or equal to target.
Returns true iff there is such * an entry.
Behaves as if written:
* public boolean skipTo(Term target) {
* do {
* if (!next())
* return false;
* } while (target > term());
* return true;
* }
*
* Some implementations are considerably more efficient than that.
*/
virtual bool skipTo(Term* target);
};
/**
* TermPositions provides an interface for enumerating the <document,
* frequency, <position>* > tuples for a term. The document and * frequency are the same as for a TermDocs. The positions portion lists the ordinal * positions of each occurrence of a term in a document. * * @see IndexReader#termPositions() */ class CLUCENE_EXPORT TermPositions: public virtual TermDocs { public: /** Returns next position in the current document. It is an error to call this more than {@link #freq()} times without calling {@link #next()}
This is
invalid until {@link #next()} is called for
the first time.
*/
virtual int32_t nextPosition() = 0;
virtual ~TermPositions();
/**
* Returns the length of the payload at the current term position.
* This is invalid until {@link #nextPosition()} is called for
* the first time.
* @return length of the current payload in number of bytes
*/
virtual int32_t getPayloadLength() const = 0;
/**
* Returns the payload data at the current term position.
* This is invalid until {@link #nextPosition()} is called for
* the first time.
* This method must not be called more than once after each call
* of {@link #nextPosition()}. However, payloads are loaded lazily,
* so if the payload data for the current position is not needed,
* this method may not be called at all for performance reasons.
*
* @param data the array into which the data of this payload is to be
* stored, if it is big enough; otherwise, a new byte[] array
* is allocated for this purpose.
* @return a byte[] array containing the data of this payload
*/
virtual uint8_t* getPayload(uint8_t* data) = 0;
/**
* Checks if a payload can be loaded at this position.
*
* Payloads can only be loaded once per call to * {@link #nextPosition()}. * * @return true if there is a payload available at this position that can be loaded */ virtual bool isPayloadAvailable() const = 0; /** Solve the diamond inheritence problem by providing a reinterpret function. * No dynamic casting is required and no RTTI data is needed to do this */ virtual TermDocs* __asTermDocs()=0; virtual TermPositions* __asTermPositions()=0; }; CL_NS_END #endif