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_, MultiMatch matcher_, Xapian::termcount doclen_lower_bound_, bool wdf_disjoint_)

	~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 () const
	Return the weight contribution for the current position. More...

double	get_maxweight () const
	Return an upper bound on what get_weight() can return. More...

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

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

Xapian::doccount	get_termfreq_min () const
	Get a lower bound on the number of documents indexed by this term. More...

Xapian::doccount	get_termfreq_est () const
	Get an estimate of the number of documents indexed by this term. More...

Xapian::doccount	get_termfreq_max () const
	Get an upper bound on the number of documents indexed by this term. More...

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

Xapian::termcount	get_doclength () const
	Return the length of current document. More...

Xapian::termcount	get_unique_terms () const
	Return the number of unique terms in the current document. More...

bool	at_end () const
	Return true if the current position is past the last entry in this list. 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 Xapian::PostingIterator::Internal
virtual	~Internal ()
	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...

virtual TermFreqs	get_termfreq_est_using_stats (const Xapian::Weight::Internal &stats) const
	Get an estimate for the termfreq and reltermfreq, given the stats. More...

virtual const std::string *	get_sort_key () const

virtual const std::string *	get_collapse_key () const
	If the collapse key is already known, return it. More...

virtual 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...

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

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

Internal *	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...

Public Member Functions inherited from Xapian::Internal::intrusive_base
	intrusive_base ()
	Construct with no references. More...

Private Attributes
PostList *	subtree
	The subtree, which starts as an OR of all the sub-postlists being joined with Synonym, but may decay into something else. More...

MultiMatch *	matcher
	The object which is using this postlist to perform a match. More...

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

bool	want_doclength
	Flag indicating whether the weighting object needs the doclength. More...

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

bool	want_unique_terms
	Flag indicating whether the weighting object needs the number of unique terms. More...

bool	wdf_disjoint
	Are the subquery's wdf contributions disjoint? More...

Xapian::termcount	doclen_lower_bound
	Lower bound on doclength in the subdatabase we're working over. More...

Additional Inherited Members
Public Attributes inherited from Xapian::Internal::intrusive_base
unsigned	_refs
	Reference count. More...

Protected Member Functions inherited from Xapian::PostingIterator::Internal
	Internal ()
	Only constructable as a base class for derived classes. 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.

Definition at line 34 of file synonympostlist.h.

Constructor & Destructor Documentation

◆ SynonymPostList()

SynonymPostList::SynonymPostList	(	PostList *	subtree_,
		MultiMatch *	matcher_,
		Xapian::termcount	doclen_lower_bound_,
		bool	wdf_disjoint_
	)

inline

Definition at line 74 of file synonympostlist.h.

References at_end(), count_matching_subqs(), get_description(), get_docid(), get_doclength(), get_maxweight(), get_termfreq_est(), get_termfreq_max(), get_termfreq_min(), get_unique_terms(), get_wdf(), get_weight(), Xapian::PostingIterator::Internal::next(), recalc_maxweight(), set_weight(), skip_to(), and ~SynonymPostList().

◆ ~SynonymPostList()

SynonymPostList::~SynonymPostList ( )

Definition at line 31 of file synonympostlist.cc.

References subtree, and wt.

Referenced by SynonymPostList().

Member Function Documentation

◆ at_end()

bool SynonymPostList::at_end ( ) const

virtual

Return true if the current position is past the last entry in this list.

Implements Xapian::PostingIterator::Internal.

Definition at line 156 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::at_end(), LOGCALL, RETURN, and subtree.

Referenced by SynonymPostList().

◆ 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::PostingIterator::Internal.

Definition at line 162 of file synonympostlist.cc.

Referenced by SynonymPostList().

◆ get_description()

std::string SynonymPostList::get_description ( ) const

virtual

Return a string description of this object.

Implements Xapian::PostingIterator::Internal.

Definition at line 168 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_description(), and subtree.

Referenced by SynonymPostList().

◆ get_docid()

Xapian::docid SynonymPostList::get_docid ( ) const

virtual

Return the current docid.

Implements Xapian::PostingIterator::Internal.

Definition at line 138 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_docid(), LOGCALL, RETURN, and subtree.

Referenced by SynonymPostList().

◆ get_doclength()

Xapian::termcount SynonymPostList::get_doclength ( ) const

virtual

Return the length of current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 144 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_doclength(), LOGCALL, RETURN, and subtree.

Referenced by get_weight(), and SynonymPostList().

◆ get_maxweight()

double SynonymPostList::get_maxweight ( ) const

virtual

Return an upper bound on what get_weight() can return.

Implements Xapian::PostingIterator::Internal.

Definition at line 100 of file synonympostlist.cc.

References Xapian::Weight::get_maxpart(), LOGCALL, RETURN, and wt.

Referenced by recalc_maxweight(), and SynonymPostList().

◆ get_termfreq_est()

Xapian::doccount SynonymPostList::get_termfreq_est ( ) const

virtual

Get an estimate of the number of documents indexed by this term.

It should always be true that: get_termfreq_min() <= get_termfreq_est() <= get_termfreq_max()

Implements Xapian::PostingIterator::Internal.

Definition at line 126 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_est(), LOGCALL, RETURN, and subtree.

Referenced by SynonymPostList().

◆ get_termfreq_max()

Xapian::doccount SynonymPostList::get_termfreq_max ( ) const

virtual

Get an upper bound on the number of documents indexed by this term.

Implements Xapian::PostingIterator::Internal.

Definition at line 132 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_max(), LOGCALL, RETURN, and subtree.

Referenced by SynonymPostList().

◆ get_termfreq_min()

Xapian::doccount SynonymPostList::get_termfreq_min ( ) const

virtual

Get a lower bound on the number of documents indexed by this term.

Implements Xapian::PostingIterator::Internal.

Definition at line 120 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_min(), LOGCALL, RETURN, and subtree.

Referenced by SynonymPostList().

◆ get_unique_terms()

Xapian::termcount SynonymPostList::get_unique_terms ( ) const

virtual

Return the number of unique terms in the current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 150 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_unique_terms(), LOGCALL, RETURN, and subtree.

Referenced by get_weight(), and SynonymPostList().

◆ get_wdf()

Xapian::termcount SynonymPostList::get_wdf ( ) const

virtual

Return the wdf for the document at the current position.

The default implementation throws Xapian::UnimplementedError.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 114 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_wdf(), LOGCALL, RETURN, and subtree.

Referenced by get_weight(), and SynonymPostList().

◆ get_weight()

double SynonymPostList::get_weight ( ) const

virtual

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 66 of file synonympostlist.cc.

References AssertRel, doclen_lower_bound, get_doclength(), Xapian::Weight::get_maxpart(), Xapian::Weight::get_sumpart(), get_unique_terms(), get_wdf(), LOGCALL, RETURN, want_doclength, want_unique_terms, want_wdf, wdf_disjoint, and wt.

Referenced by SynonymPostList().

◆ 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::PostingIterator::Internal.

Definition at line 48 of file synonympostlist.cc.

References LOGCALL, matcher, next_handling_prune(), RETURN, and subtree.

◆ recalc_maxweight()

double SynonymPostList::recalc_maxweight ( )

virtual

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

If the tree has pruned, get_maxweight() may use cached values. Calling this method instead forces a full recalculation.

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

Implements Xapian::PostingIterator::Internal.

Definition at line 107 of file synonympostlist.cc.

References get_maxweight(), LOGCALL, and RETURN.

Referenced by SynonymPostList().

◆ 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_doclength_(), Xapian::Weight::get_sumpart_needs_uniqueterms_(), Xapian::Weight::get_sumpart_needs_wdf_(), want_doclength, want_unique_terms, want_wdf, and wt.

Referenced by SynonymPostList().

◆ 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::PostingIterator::Internal.

Definition at line 57 of file synonympostlist.cc.

References LOGCALL, matcher, RETURN, skip_to_handling_prune(), and subtree.

Referenced by SynonymPostList().

Member Data Documentation

◆ doclen_lower_bound

Xapian::termcount SynonymPostList::doclen_lower_bound

private

Lower bound on doclength in the subdatabase we're working over.

Definition at line 71 of file synonympostlist.h.

Referenced by get_weight().

◆ matcher

MultiMatch* SynonymPostList::matcher

private

The object which is using this postlist to perform a match.

This object needs to be notified when the tree changes such that the maximum weights need to be recalculated.

Definition at line 45 of file synonympostlist.h.

Referenced by next(), and skip_to().

◆ subtree

PostList* SynonymPostList::subtree

private

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

Definition at line 38 of file synonympostlist.h.

Referenced by at_end(), get_description(), get_docid(), get_doclength(), get_termfreq_est(), get_termfreq_max(), get_termfreq_min(), get_unique_terms(), get_wdf(), next(), skip_to(), and ~SynonymPostList().

◆ want_doclength

bool SynonymPostList::want_doclength

private

Flag indicating whether the weighting object needs the doclength.

Definition at line 51 of file synonympostlist.h.

Referenced by get_weight(), and set_weight().

◆ want_unique_terms

bool SynonymPostList::want_unique_terms

private

Flag indicating whether the weighting object needs the number of unique terms.

Definition at line 59 of file synonympostlist.h.

Referenced by get_weight(), and set_weight().

◆ want_wdf

bool SynonymPostList::want_wdf

private

Flag indicating whether the weighting object needs the wdf.

Definition at line 54 of file synonympostlist.h.

Referenced by get_weight(), and set_weight().

◆ wdf_disjoint

bool SynonymPostList::wdf_disjoint

private

Are the subquery's wdf contributions disjoint?

This is true is 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 can avoid the need to check and clamp wdf to be <= document length.

Definition at line 68 of file synonympostlist.h.

Referenced by get_weight().

◆ wt

const Xapian::Weight* SynonymPostList::wt

private

Weighting object used for calculating the synonym weights.

Definition at line 48 of file synonympostlist.h.

Referenced by get_maxweight(), get_weight(), set_weight(), and ~SynonymPostList().

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

◆ at_end()

◆ count_matching_subqs()

◆ get_description()

◆ get_docid()

◆ get_doclength()

◆ get_maxweight()

◆ get_termfreq_est()

◆ get_termfreq_max()

◆ get_termfreq_min()

◆ get_unique_terms()

◆ get_wdf()

◆ get_weight()

◆ next()

◆ recalc_maxweight()

◆ set_weight()

◆ skip_to()

Member Data Documentation

◆ doclen_lower_bound

◆ matcher

◆ subtree

◆ want_doclength

◆ want_unique_terms

◆ want_wdf

◆ wdf_disjoint

◆ wt