A postlist comprising several postlists SYNONYMed together. More...

#include <synonympostlist.h>

Inheritance diagram for SynonymPostList:

Collaboration diagram for SynonymPostList:

Public Member Functions
	SynonymPostList (PostList subtree, PostListTree pltree_, bool needs_doclen_)

	~SynonymPostList ()

void	set_weight (const Xapian::Weight *wt_)
	Set the weight object to be used for the synonym postlist. More...

PostList *	next (double w_min)
	Advance the current position to the next document in the postlist. More...

PostList *	skip_to (Xapian::docid did, double w_min)
	Skip forward to the specified docid. More...

double	get_weight (Xapian::termcount doclen, Xapian::termcount unique_terms, Xapian::termcount wdfdocmax) const
	Return the weight contribution for the current position. More...

double	recalc_maxweight ()
	Recalculate the upper bound on what get_weight() can return. More...

Xapian::termcount	count_matching_subqs () const
	Count the number of leaf subqueries which match at the current position. More...

std::string	get_description () const
	Return a string description of this object. More...

Public Member Functions inherited from WrapperPostList
	WrapperPostList (PostList *pl_)

	~WrapperPostList ()

Xapian::docid	get_docid () const
	Return the current docid. More...

double	get_weight (Xapian::termcount doclen, Xapian::termcount unique_terms, Xapian::termcount wdfdocmax) const
	Return the weight contribution for the current position. More...

bool	at_end () const
	Return true if the current position is past the last entry in this list. More...

double	recalc_maxweight ()
	Recalculate the upper bound on what get_weight() can return. More...

PositionList *	read_position_list ()
	Read the position list for the term in the current document and return a pointer to it (owned by the PostList). More...

PostList *	next (double w_min)
	Advance the current position to the next document in the postlist. More...

PostList *	skip_to (Xapian::docid, double w_min)
	Skip forward to the specified docid. More...

std::string	get_description () const
	Return a string description of this object. More...

Xapian::termcount	get_wdf () const
	Return the wdf for the document at the current position. More...

Xapian::termcount	count_matching_subqs () const
	Count the number of leaf subqueries which match at the current position. More...

Public Member Functions inherited from Xapian::Internal::PostList
virtual	~PostList ()
	We have virtual methods and want to be able to delete derived classes using a pointer to the base class, so we need a virtual destructor. More...

Xapian::doccount	get_termfreq () const
	Get an estimate of the number of documents this PostList will return. More...

virtual PositionList *	open_position_list () const
	Read the position list for the term in the current document and return a pointer to it (not owned by the PostList). More...

virtual PostList *	check (Xapian::docid did, double w_min, bool &valid)
	Check if the specified docid occurs in this postlist. More...

PostList *	next ()
	Advance the current position to the next document in the postlist. More...

PostList *	skip_to (Xapian::docid did)
	Skip forward to the specified docid. More...

virtual void	gather_position_lists (OrPositionList *orposlist)
	Gather PositionList* objects for a subtree. More...

virtual void	get_docid_range (docid &first, docid &last) const
	Get the bounds on the range of docids this PostList can return. More...

Private Attributes
const Xapian::Weight *	wt = nullptr
	Weighting object used for calculating the synonym weights. More...

bool	want_wdf = false
	Flag indicating whether the weighting object needs the wdf. More...

bool	want_wdfdocmax = false
	Flag indicating whether the weighting object needs the wdfdocmax. More...

bool	needs_doclen
	Does the synonym need the document length? More...

PostListTree *	pltree

Additional Inherited Members
Protected Member Functions inherited from Xapian::Internal::PostList
	PostList ()
	Only constructable as a base class for derived classes. More...

Protected Attributes inherited from WrapperPostList
PostList *	pl

Protected Attributes inherited from Xapian::Internal::PostList
Xapian::doccount	termfreq
	Estimate of the number of documents this PostList will return. More...

Detailed Description

A postlist comprising several postlists SYNONYMed together.

This postlist returns all postings in the OR of the sub postlists, but returns weights as if they represented a single term. The term frequency portion of the weight is approximated.

The wrapped postlist starts as an OR of all the sub-postlists being joined with Synonym, but may decay into something else.

Definition at line 40 of file synonympostlist.h.

Constructor & Destructor Documentation

◆ SynonymPostList()

SynonymPostList::SynonymPostList	(	PostList *	subtree,
		PostListTree *	pltree_,
		bool	needs_doclen_
	)

inline

Definition at line 68 of file synonympostlist.h.

◆ ~SynonymPostList()

SynonymPostList::~SynonymPostList ( )

Definition at line 32 of file synonympostlist.cc.

Member Function Documentation

◆ count_matching_subqs()

Xapian::termcount SynonymPostList::count_matching_subqs ( ) const

virtual

Count the number of leaf subqueries which match at the current position.

Reimplemented from Xapian::Internal::PostList.

Definition at line 106 of file synonympostlist.cc.

◆ get_description()

string SynonymPostList::get_description ( ) const

virtual

Return a string description of this object.

Implements Xapian::Internal::PostList.

Definition at line 112 of file synonympostlist.cc.

◆ get_weight()

double SynonymPostList::get_weight	(	Xapian::termcount	doclen,
		Xapian::termcount	unique_terms,
		Xapian::termcount	wdfdocmax
	)		const

virtual

Return the weight contribution for the current position.

Implements Xapian::Internal::PostList.

Definition at line 63 of file synonympostlist.cc.

References WrapperPostList::get_wdf(), LOGCALL, and RETURN.

◆ next()

PostList * SynonymPostList::next ( double w_min )

virtual

Advance the current position to the next document in the postlist.

The list starts before the first entry in the list, so next(), skip_to() or check() must be called before any methods which need the context of the current position.

Parameters

w_min The minimum weight contribution that is needed (this is just a hint which PostList subclasses may ignore).

Returns: If a non-NULL pointer is returned, then the caller should substitute the returned pointer for its pointer to us, and then delete us. This "pruning" can only happen for a non-leaf subclass of this class.

Implements Xapian::Internal::PostList.

Definition at line 47 of file synonympostlist.cc.

References LOGCALL, Xapian::Internal::PostList::next(), and RETURN.

◆ recalc_maxweight()

double SynonymPostList::recalc_maxweight ( )

virtual

Recalculate the upper bound on what get_weight() can return.

The maximum weight that get_weight() can return can decrease as the match progresses (typically when the PostList tree prunes) - calling this method calculates a current upper bound.

Note that this method may be called after the postlist has reached the end. In this situation, the method should return 0.

Implements Xapian::Internal::PostList.

Definition at line 99 of file synonympostlist.cc.

References LOGCALL, and RETURN.

◆ set_weight()

void SynonymPostList::set_weight ( const Xapian::Weight * wt_ )

Set the weight object to be used for the synonym postlist.

Ownership of the weight object passes to the synonym postlist - the caller must not delete it after use.

Definition at line 38 of file synonympostlist.cc.

References Xapian::Weight::get_sumpart_needs_wdf_().

◆ skip_to()

PostList * SynonymPostList::skip_to	(	Xapian::docid	did,
		double	w_min
	)

virtual

Skip forward to the specified docid.

If the specified docid isn't in the list, position ourselves on the first document after it (or at_end() if no greater docids are present).

Parameters

w_min The minimum weight contribution that is needed (this is just a hint which PostList subclasses may ignore).

Returns: If a non-NULL pointer is returned, then the caller should substitute the returned pointer for its pointer to us, and then delete us. This "pruning" can only happen for a non-leaf subclass of this class.

Implements Xapian::Internal::PostList.

Definition at line 55 of file synonympostlist.cc.

References LOGCALL, RETURN, and WrapperPostList::skip_to().

Member Data Documentation

◆ needs_doclen

bool SynonymPostList::needs_doclen

private

Does the synonym need the document length?

This is true if either of these are true:

Each wdf from the document contributes at most itself to the wdf of the subquery. That means that the wdf of the subquery can't possibly ever exceed the document length, so we don't need to check and clamp wdf to be <= document length.

Or the weighting scheme in use doesn't use document length, in which case we assume that it doesn't rely on wdf <= document_length being an invariant, and so we don't enforce it.

Definition at line 63 of file synonympostlist.h.

◆ pltree

PostListTree* SynonymPostList::pltree

private

Definition at line 65 of file synonympostlist.h.

◆ want_wdf

bool SynonymPostList::want_wdf = false

private

Flag indicating whether the weighting object needs the wdf.

Definition at line 45 of file synonympostlist.h.

◆ want_wdfdocmax

bool SynonymPostList::want_wdfdocmax = false

private

Flag indicating whether the weighting object needs the wdfdocmax.

Definition at line 48 of file synonympostlist.h.

◆ wt

const Xapian::Weight* SynonymPostList::wt = nullptr

private

Weighting object used for calculating the synonym weights.

Definition at line 42 of file synonympostlist.h.

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

matcher/synonympostlist.h
matcher/synonympostlist.cc

Public Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ SynonymPostList()

◆ ~SynonymPostList()

Member Function Documentation

◆ count_matching_subqs()

◆ get_description()

◆ get_weight()

◆ next()

◆ recalc_maxweight()

◆ set_weight()

◆ skip_to()

Member Data Documentation

◆ needs_doclen

◆ pltree

◆ want_wdf

◆ want_wdfdocmax

◆ wt