Xapian::Query

Xapian::Query Class Reference

Class representing a query. More...

#include <query.h>

Collaboration diagram for Xapian::Query:


Public Types
enum	op { OP_AND, OP_OR, OP_AND_NOT, OP_XOR, OP_AND_MAYBE, OP_FILTER, OP_NEAR, OP_PHRASE, OP_VALUE_RANGE, OP_SCALE_WEIGHT, OP_ELITE_SET, OP_VALUE_GE, OP_VALUE_LE }
	Enum of possible query operations. More...
Public Member Functions
	Query (const Query &copyme)
	Copy constructor.
Query &	operator= (const Query &copyme)
	Assignment.
	Query ()
	Default constructor: makes an empty query which matches no documents.
	~Query ()
	Destructor.
	Query (const std::string &tname_, Xapian::termcount wqf_=1, Xapian::termpos pos_=0)
	A query consisting of a single term.
	Query (Query::op op_, const Query &left, const Query &right)
	A query consisting of two subqueries, opp-ed together.
	Query (Query::op op_, const std::string &left, const std::string &right)
	A query consisting of two termnames opp-ed together.
template<class Iterator>
	Query (Query::op op_, Iterator qbegin, Iterator qend, Xapian::termcount parameter=0)
	Combine a number of Xapian::Query-s with the specified operator.
	Query (Query::op op_, Xapian::Query q)
	Apply the specified operator to a single Xapian::Query object.
	Query (Query::op op_, Xapian::Query q, double parameter)
	Apply the specified operator to a single Xapian::Query object, with a double parameter.
	Query (Query::op op_, Xapian::valueno valno, const std::string &begin, const std::string &end)
	Construct a value range query on a document value.
	Query (Query::op op_, Xapian::valueno valno, const std::string &value)
	Construct a value comparison query on a document value.
Xapian::termcount	get_length () const
	Get the length of the query, used by some ranking formulae.
TermIterator	get_terms_begin () const
	Return a Xapian::TermIterator returning all the terms in the query, in order of termpos.
TermIterator	get_terms_end () const
	Return a Xapian::TermIterator to the end of the list of terms in the query.
bool	empty () const
	Test if the query is empty (i.e.
std::string	get_description () const
	Return a string describing this object.
Static Public Attributes
static Xapian::Query	MatchAll = Xapian::Query(string())
	A query which matches all documents in the database.
static Xapian::Query	MatchNothing = Xapian::Query()
	A query which matches no documents.
Private Member Functions
void	add_subquery (const Query &subq)
	Add a subquery by reference.
void	add_subquery (const Query *subq)
	Add a subquery by pointer.
void	add_subquery (const std::string &tname)
void	start_construction (Query::op op_, Xapian::termcount parameter)
	Setup the internals for the query, with the appropriate operator.
void	end_construction ()
	Check that query has an appropriate number of arguments, etc,.
void	abort_construction ()
	Abort construction of the query: delete internal.
Private Attributes
Xapian::Internal::RefCntPtr< Internal >	internal
	For internal use only. Reference counted internals.
Classes
class	Internal
	For internal use only. Internal class, implementing most of Xapian::Query. More...

Detailed Description

Class representing a query.

Queries are represented as a tree of objects.

Definition at line 51 of file query.h.

Member Enumeration Documentation

enum Xapian::Query::op

Enum of possible query operations.

Enumerator:

OP_AND	Return iff both subqueries are satisfied.
OP_OR	Return if either subquery is satisfied.
OP_AND_NOT	Return if left but not right satisfied.
OP_XOR	Return if one query satisfied, but not both.
OP_AND_MAYBE	Return iff left satisfied, but use weights from both.
OP_FILTER	As AND, but use only weights from left subquery.
OP_NEAR	Find occurrences of a list of terms with all the terms occurring within a specified window of positions. Each occurrence of a term must be at a different position, but the order they appear in is irrelevant. The window parameter should be specified for this operation, but will default to the number of terms in the list.
OP_PHRASE	Find occurrences of a list of terms with all the terms occurring within a specified window of positions, and all the terms appearing in the order specified. Each occurrence of a term must be at a different position. The window parameter should be specified for this operation, but will default to the number of terms in the list.
OP_VALUE_RANGE	Filter by a range test on a document value.
OP_SCALE_WEIGHT	Scale the weight of a subquery by the specified factor. A factor of 0 means this subquery will contribute no weight to the query - it will act as a purely boolean subquery. If the factor is negative, Xapian::InvalidArgumentError will be thrown.
OP_ELITE_SET	Select an elite set from the subqueries, and perform a query with these combined as an OR query.
OP_VALUE_GE	Filter by a greater-than-or-equal test on a document value.
OP_VALUE_LE	Filter by a less-than-or-equal test on a document value.

Definition at line 59 of file query.h.

Constructor & Destructor Documentation

Xapian::Query::Query ( const Query & copyme )

Copy constructor.

Definition at line 175 of file omquery.cc.

References DEBUGAPICALL.

Xapian::Query::Query ( )

Default constructor: makes an empty query which matches no documents.

Also useful for defining a Query object to be assigned to later.

An exception will be thrown if an attempt is made to use an undefined query when building up a composite query.

Definition at line 191 of file omquery.cc.

References DEBUGAPICALL.

Xapian::Query::~Query ( )

Destructor.

Definition at line 197 of file omquery.cc.

References DEBUGAPICALL.

Xapian::Query::Query	(	const std::string &	tname_,
		Xapian::termcount	wqf_ = `1`,
		Xapian::termpos	pos_ = `0`
	)

A query consisting of a single term.

Xapian::Query::Query	(	Query::op	op_,
		const Query &	left,
		const Query &	right
	)

A query consisting of two subqueries, opp-ed together.

Definition at line 106 of file omquery.cc.

References abort_construction(), add_subquery(), DEBUGAPICALL, and end_construction().

Xapian::Query::Query	(	Query::op	op_,
		const std::string &	left,
		const std::string &	right
	)

A query consisting of two termnames opp-ed together.

Definition at line 231 of file omquery.cc.

References abort_construction(), add_subquery(), end_construction(), and start_construction().

template<class Iterator>

Xapian::Query::Query	(	Query::op	op_,
		Iterator	qbegin,
		Iterator	qend,
		Xapian::termcount	parameter = `0`
	)			`[inline]`

Combine a number of Xapian::Query-s with the specified operator.

The Xapian::Query objects are specified with begin and end iterators.

AND, OR, NEAR and PHRASE can take any number of subqueries. Other operators take exactly two subqueries.

The iterators may be to Xapian::Query objects, pointers to Xapian::Query objects, or termnames (std::string-s).

For NEAR and PHRASE, a window size can be specified in parameter.

For ELITE_SET, the elite set size can be specified in parameter.

Definition at line 258 of file query.h.

References abort_construction(), add_subquery(), end_construction(), and start_construction().

Xapian::Query::Query	(	Query::op	op_,
		Xapian::Query	q
	)

Apply the specified operator to a single Xapian::Query object.

Deprecated:: This method is deprecated because it isn't useful, since none of the current query operators can be usefully applied to a single subquery with a parameter value.

Definition at line 121 of file omquery.cc.

References abort_construction(), add_subquery(), end_construction(), and start_construction().

Xapian::Query::Query	(	Query::op	op_,
		Xapian::Query	q,
		double	parameter
	)

Apply the specified operator to a single Xapian::Query object, with a double parameter.

Definition at line 133 of file omquery.cc.

References abort_construction(), add_subquery(), DEBUGAPICALL, end_construction(), Xapian::Internal::RefCntPtr< T >::get(), internal, OP_SCALE_WEIGHT, OP_VALUE_GE, OP_VALUE_LE, OP_VALUE_RANGE, and start_construction().

Xapian::Query::Query	(	Query::op	op_,
		Xapian::valueno	valno,
		const std::string &	begin,
		const std::string &	end
	)

Construct a value range query on a document value.

A value range query matches those documents which have a value stored in the slot given by valno which is in the range specified by begin and end (in lexicographical order), including the endpoints.

Parameters:

	op_	The operator to use for the query. Currently, must be OP_VALUE_RANGE.
	valno	The slot number to get the value from.
	begin	The start of the range.
	end	The end of the range.

Xapian::Query::Query	(	Query::op	op_,
		Xapian::valueno	valno,
		const std::string &	value
	)

Construct a value comparison query on a document value.

This query matches those documents which have a value stored in the slot given by valno which compares, as specified by the operator, to value.

Parameters:

	op_	The operator to use for the query. Currently, must be OP_VALUE_GE or OP_VALUE_LE.
	valno	The slot number to get the value from.
	value	The value to compare.

Definition at line 167 of file omquery.cc.

References DEBUGAPICALL.