lucene::document::Field Class Reference

A field is a section of a Document. More...

#include <Field.h>

Inheritance diagram for lucene::document::Field:

Public Types
enum	Store { STORE_YES = 1, STORE_NO = 2, STORE_COMPRESS = 4 }
enum	Index { INDEX_NO = 16, INDEX_TOKENIZED = 32, INDEX_UNTOKENIZED = 64, INDEX_NONORMS = 128 }
enum	TermVector { TERMVECTOR_NO = 256, TERMVECTOR_YES = 512, TERMVECTOR_WITH_POSITIONS = 1024, TERMVECTOR_WITH_OFFSETS = 2048 }
Public Member Functions
	Field (const TCHAR name, const TCHAR value, bool store, bool index, bool token, const bool storeTermVector=false)
	Field (const TCHAR name, lucene::util::Reader reader, bool store, bool index, bool token, const bool storeTermVector=false)
	Field (const TCHAR name, const TCHAR value, int configs)
	Field (const TCHAR name, lucene::util::Reader reader, int configs)
	Field (const TCHAR name, jstreams::StreamBase< char > stream, int configs)
	~Field ()
const TCHAR *	name ()
	The name of the field (e.g., "date", "subject", "title", "body", etc.
TCHAR *	stringValue ()
	The value of the field as a String, or null.
lucene::util::Reader *	readerValue ()
	The value of the field as a reader, or null.
jstreams::StreamBase< char > *	streamValue ()
	The value of the field as a String, or null.
bool	isStored ()
bool	isIndexed ()
bool	isTokenized ()
bool	isCompressed ()
	True if the value of the field is stored and compressed within the index NOTE: CLucene does not actually support compressed fields, Instead, a reader will be returned with a pointer to a SubIndexInputStream.
void	setConfig (int termVector)
bool	isTermVectorStored ()
	True iff the term or terms used to index this field are stored as a term vector, available from IndexReader#getTermFreqVector(int32_t,TCHAR*).
bool	isStoreOffsetWithTermVector ()
	True iff terms are stored as term vector together with their offsets (start and end positon in source text).
bool	isStorePositionWithTermVector ()
	True iff terms are stored as term vector together with their token positions.
float_t	getBoost ()
	Returns the boost factor for hits for this field.
void	setBoost (float_t value)
	Sets the boost factor hits on this field.
bool	isBinary ()
	True iff the value of the filed is stored as binary.
bool	getOmitNorms ()
	True if norms are omitted for this indexed field.
void	setOmitNorms (bool omitNorms)
	Expert:.
TCHAR *	toString ()
Static Public Member Functions
static Field *	Keyword (const TCHAR name, const TCHAR value)
	Constructs a String-valued Field that is not tokenized, but is indexed and stored.
static Field *	UnIndexed (const TCHAR name, const TCHAR value)
	Constructs a String-valued Field that is not tokenized nor indexed, but is stored in the index, for return with hits.
static Field *	Text (const TCHAR name, const TCHAR value, const bool storeTermVector=false)
	Constructs a String-valued Field that is tokenized and indexed, and is stored in the index, for return with hits.
static Field *	UnStored (const TCHAR name, const TCHAR value, const bool storeTermVector=false)
	Constructs a String-valued Field that is tokenized and indexed, but that is not stored in the index.
static Field *	Text (const TCHAR name, lucene::util::Reader value, const bool storeTermVector=false)
	Constructs a Reader-valued Field that is tokenized and indexed, but is not stored in the index verbatim.

Detailed Description

A field is a section of a Document.

Each field has two parts, a name and a value. Values may be free text, provided as a String or as a Reader, or they may be atomic keywords, which are not further processed. Such keywords may be used to represent dates, urls, etc. Fields are optionally stored in the index, so that they may be returned with hits on the document.

PORTING: CLucene doesn't directly support compressed fields. However, it is easy to reproduce this functionality by using the GZip streams in the contrib package. Also note that binary fields are not read immediately in CLucene, a substream is pointed directly to the field's data, in affect creating a lazy load ability. This means that large fields are best saved in binary format (even if they are text), so that they can be loaded lazily.

Member Enumeration Documentation

enum lucene::document::Field::Index

Enumerator:

INDEX_NO	Do not index the field value. This field can thus not be searched, but one can still access its contents provided it is stored.
INDEX_TOKENIZED	Index the field's value so it can be searched. An Analyzer will be used to tokenize and possibly further normalize the text before its terms will be stored in the index. This is useful for common text.
INDEX_UNTOKENIZED	Index the field's value without using an Analyzer, so it can be searched. As no analyzer is used the value will be stored as a single term. This is useful for unique Ids like product numbers.
INDEX_NONORMS	Index the field's value without an Analyzer, and disable the storing of norms. No norms means that index-time boosting and field length normalization will be disabled. The benefit is less memory usage as norms take up one byte per indexed field for every document in the index.

enum lucene::document::Field::Store

Enumerator:

STORE_YES

Store the original field value in the index.

This is useful for short texts like a document's title which should be displayed with the results. The value is stored in its original form, i.e. no analyzer is used before it is stored.

STORE_NO

Do not store the field value in the index.

STORE_COMPRESS

Store the original field value in the index in a compressed form.

This is useful for long documents and for binary valued fields. NOTE: CLucene does not directly support compressed fields, to store a compressed field. //TODO: need better documentation on how to add a compressed field //because actually we still need to write a GZipOutputStream...

enum lucene::document::Field::TermVector

Enumerator:

TERMVECTOR_NO	Do not store term vectors.
TERMVECTOR_YES	Store the term vectors of each document. A term vector is a list of the document's terms and their number of occurences in that document.
TERMVECTOR_WITH_POSITIONS	Store the term vector + token position information. See also: YES
TERMVECTOR_WITH_OFFSETS	Store the term vector + Token offset information. See also: YES

Constructor & Destructor Documentation

lucene::document::Field::Field	(	const TCHAR *	name,
		const TCHAR *	value,
		bool	store,
		bool	index,
		bool	token,
		const bool	storeTermVector = `false`
	)

lucene::document::Field::Field	(	const TCHAR *	name,
		lucene::util::Reader *	reader,
		bool	store,
		bool	index,
		bool	token,
		const bool	storeTermVector = `false`
	)

lucene::document::Field::Field	(	const TCHAR *	name,
		const TCHAR *	value,
		int	configs
	)

lucene::document::Field::Field	(	const TCHAR *	name,
		lucene::util::Reader *	reader,
		int	configs
	)

lucene::document::Field::Field	(	const TCHAR *	name,
		jstreams::StreamBase< char > *	stream,
		int	configs
	)

lucene::document::Field::~Field ( )

Member Function Documentation

float_t lucene::document::Field::getBoost ( )

Returns the boost factor for hits for this field.

The default value is 1.0.

Note: this value is not stored directly with the document in the index. Documents returned from IndexReader#document(int) and Hits#doc(int) may thus not have the same value present as when this field was indexed.

See also:: setBoost(float)

bool lucene::document::Field::getOmitNorms ( )

True if norms are omitted for this indexed field.

bool lucene::document::Field::isBinary ( )

True iff the value of the filed is stored as binary.

bool lucene::document::Field::isCompressed ( )

True if the value of the field is stored and compressed within the index NOTE: CLucene does not actually support compressed fields, Instead, a reader will be returned with a pointer to a SubIndexInputStream.

A GZipInputStream and a UTF8 reader must be used to actually read the content. This flag will only be set if the index was created by another lucene implementation.

bool lucene::document::Field::isIndexed ( )

bool lucene::document::Field::isStored ( )

bool lucene::document::Field::isStoreOffsetWithTermVector ( )

True iff terms are stored as term vector together with their offsets (start and end positon in source text).

bool lucene::document::Field::isStorePositionWithTermVector ( )

True iff terms are stored as term vector together with their token positions.

bool lucene::document::Field::isTermVectorStored ( )

True iff the term or terms used to index this field are stored as a term vector, available from IndexReader#getTermFreqVector(int32_t,TCHAR*).

These methods do not provide access to the original content of the field, only to terms used to index it. If the original content must be preserved, use the stored attribute instead.

See also:: IndexReader::getTermFreqVector(int32_t, String)

bool lucene::document::Field::isTokenized ( )

static Field* lucene::document::Field::Keyword	(	const TCHAR *	name,
		const TCHAR *	value
	)			`[static]`

Constructs a String-valued Field that is not tokenized, but is indexed and stored.

Useful for non-text fields, e.g. date or url.

Deprecated:: Use new Field(name,value,Field::STORE_YES | Field::INDEX_UNTOKENIZED)

const TCHAR* lucene::document::Field::name ( )

The name of the field (e.g., "date", "subject", "title", "body", etc.

) as an interned string. returns reference

lucene:: util ::Reader* lucene::document::Field::readerValue ( )

The value of the field as a reader, or null.

If null, the String value or stream value is used. Exactly one of stringValue(), readerValue() and streamValue() must be set.

void lucene::document::Field::setBoost ( float_t value )

Sets the boost factor hits on this field.

This value will be multiplied into the score of all hits on this this field of this document.

The boost is multiplied by Document#getBoost() of the document containing this field. If a document has multiple fields with the same name, all such values are multiplied together. This product is then multipled by the value Similarity#lengthNorm(String,int), and rounded by Similarity#encodeNorm(float) before it is stored in the index. One should attempt to ensure that this product does not overflow the range of that encoding.

See also:: Document::setBoost(float); Similarity::lengthNorm(String, int); Similarity::encodeNorm(float)

void lucene::document::Field::setConfig ( int termVector )

void lucene::document::Field::setOmitNorms ( bool omitNorms )

Expert:.

If set, omit normalization factors associated with this indexed field. This effectively disables indexing boosts and length normalization for this field.

jstreams::StreamBase<char>* lucene::document::Field::streamValue ( )

The value of the field as a String, or null.

If null, the String value or Reader value is used. Exactly one of stringValue(), readerValue() and streamValue() must be set.

TCHAR* lucene::document::Field::stringValue ( )

The value of the field as a String, or null.

If null, the Reader value or binary value is used. Exactly one of stringValue(), readerValue() and streamValue() must be set. returns reference

static Field* lucene::document::Field::Text	(	const TCHAR *	name,
		lucene::util::Reader *	value,
		const bool	storeTermVector = `false`
	)			`[static]`

Constructs a Reader-valued Field that is tokenized and indexed, but is *not* stored in the index verbatim.

Useful for longer text fields, like "body".

Deprecated:: Use new Field(name,value, Field::INDEX_TOKENIZED)

static Field* lucene::document::Field::Text	(	const TCHAR *	name,
		const TCHAR *	value,
		const bool	storeTermVector = `false`
	)			`[static]`

Constructs a String-valued Field that is tokenized and indexed, and is stored in the index, for return with hits.

Useful for short text fields, like "title" or "subject".

Deprecated:: Use new Field(name,value,Field::STORE_YES | Field::INDEX_TOKENIZED)

TCHAR* lucene::document::Field::toString ( )

static Field* lucene::document::Field::UnIndexed	(	const TCHAR *	name,
		const TCHAR *	value
	)			`[static]`

Constructs a String-valued Field that is not tokenized nor indexed, but is stored in the index, for return with hits.

Deprecated:: Use new Field(name,value,Field::STORE_YES | Field::INDEX_NO)

static Field* lucene::document::Field::UnStored	(	const TCHAR *	name,
		const TCHAR *	value,
		const bool	storeTermVector = `false`
	)			`[static]`

Constructs a String-valued Field that is tokenized and indexed, but that is not stored in the index.

Deprecated:: Use new Field(name,value,Field::STORE_NO | Field::INDEX_TOKENIZED)

The documentation for this class was generated from the following file:

Field.h

lucene::document::Field Class Reference

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation