PostingSource subclass for injecting tf bounds and estimate. More...

Inheritance diagram for EstimatePS:

Collaboration diagram for EstimatePS:

Public Member Functions
	EstimatePS (Xapian::doccount lb_, Xapian::doccount est_, Xapian::doccount ub_)

PostingSource *	clone () const override
	Clone the posting source. More...

void	init (const Xapian::Database &) override
	Set this PostingSource to the start of the list of postings. More...

Xapian::doccount	get_termfreq_min () const override
	A lower bound on the number of documents this object can return. More...

Xapian::doccount	get_termfreq_est () const override
	An estimate of the number of documents this object can return. More...

Xapian::doccount	get_termfreq_max () const override
	An upper bound on the number of documents this object can return. More...

void	next (double) override
	Advance the current position to the next matching document. More...

void	skip_to (Xapian::docid, double) override
	Advance to the specified docid. More...

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

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

string	get_description () const override
	Return a string describing this object. More...

Public Member Functions inherited from Xapian::PostingSource
	PostingSource ()
	Allow subclasses to be instantiated. More...

virtual	~PostingSource ()

void	set_maxweight (double max_weight)
	Specify an upper bound on what get_weight() will return from now on. More...

double	get_maxweight () const
	Return the currently set upper bound on what get_weight() can return. More...

virtual double	get_weight () const
	Return the weight contribution for the current document. More...

virtual bool	check (Xapian::docid did, double min_wt)
	Check if the specified docid occurs. More...

virtual std::string	name () const
	Name of the posting source class. More...

virtual std::string	serialise () const
	Serialise object parameters into a string. More...

virtual PostingSource *	unserialise (const std::string &serialised) const
	Create object given string serialisation returned by serialise(). More...

virtual PostingSource *	unserialise_with_registry (const std::string &serialised, const Registry &registry) const
	Create object given string serialisation returned by serialise(). More...

PostingSource *	release ()
	Start reference counting this object. More...

const PostingSource *	release () const
	Start reference counting this object. More...

Public Member Functions inherited from Xapian::Internal::opt_intrusive_base
	opt_intrusive_base (const opt_intrusive_base &)

opt_intrusive_base &	operator= (const opt_intrusive_base &)

	opt_intrusive_base ()
	Construct object which is initially not reference counted. More...

virtual	~opt_intrusive_base ()

void	ref () const

void	unref () const

Private Attributes
Xapian::doccount	lb

Xapian::doccount	est

Xapian::doccount	ub

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

Protected Member Functions inherited from Xapian::Internal::opt_intrusive_base
void	release () const
	Start reference counting. More...

Detailed Description

PostingSource subclass for injecting tf bounds and estimate.

Definition at line 835 of file api_postingsource.cc.

Constructor & Destructor Documentation

◆ EstimatePS()

EstimatePS::EstimatePS	(	Xapian::doccount	lb_,
		Xapian::doccount	est_,
		Xapian::doccount	ub_
	)

inline

Definition at line 839 of file api_postingsource.cc.

Member Function Documentation

◆ at_end()

bool EstimatePS::at_end ( ) const

inlineoverridevirtual

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

At least one of next(), skip_to() or check() will be called before this method is first called.

Implements Xapian::PostingSource.

Definition at line 865 of file api_postingsource.cc.

◆ clone()

PostingSource* EstimatePS::clone ( ) const

inlineoverridevirtual

Clone the posting source.

The clone should inherit the configuration of the parent, but need not inherit the state. ie, the clone does not need to be in the same iteration position as the original: the matcher will always call init() on the clone before attempting to move the iterator, or read the information about the current position of the iterator.

This may return NULL to indicate that cloning is not supported. In this case, the PostingSource may only be used with a single-database search.

The default implementation returns NULL.

Note that the returned object will be deallocated by Xapian after use with "delete". If you want to handle the deletion in a special way (for example when wrapping the Xapian API for use from another language) then you can define a static operator delete method in your subclass as shown here: https://trac.xapian.org/ticket/554#comment:1

Reimplemented from Xapian::PostingSource.

Definition at line 845 of file api_postingsource.cc.

◆ get_description()

string EstimatePS::get_description ( ) const

inlineoverridevirtual

Return a string describing this object.

This default implementation returns a generic answer. This default it provided to avoid forcing those deriving their own PostingSource subclass from having to implement this (they may not care what get_description() gives for their subclass).

Reimplemented from Xapian::PostingSource.

Definition at line 873 of file api_postingsource.cc.

◆ get_docid()

Xapian::docid EstimatePS::get_docid ( ) const

inlineoverridevirtual

Return the current docid.

This method may assume that it will only be called when there is a "current document". See get_weight() for details.

Note: in the case of a multi-database search, the returned docid should be in the single subdatabase relevant to this posting source. See the init() method for details.

Implements Xapian::PostingSource.

Definition at line 869 of file api_postingsource.cc.

References FAIL_TEST.

◆ get_termfreq_est()

Xapian::doccount EstimatePS::get_termfreq_est ( ) const

inlineoverridevirtual

An estimate of the number of documents this object can return.

It must always be true that:

get_termfreq_min() <= get_termfreq_est() <= get_termfreq_max()

Xapian will always call init() on a PostingSource before calling this for the first time.

Implements Xapian::PostingSource.

Definition at line 853 of file api_postingsource.cc.

References est().

◆ get_termfreq_max()

Xapian::doccount EstimatePS::get_termfreq_max ( ) const

inlineoverridevirtual

An upper bound on the number of documents this object can return.

Xapian will always call init() on a PostingSource before calling this for the first time.

Implements Xapian::PostingSource.

Definition at line 855 of file api_postingsource.cc.

◆ get_termfreq_min()

Xapian::doccount EstimatePS::get_termfreq_min ( ) const

inlineoverridevirtual

A lower bound on the number of documents this object can return.

Xapian will always call init() on a PostingSource before calling this for the first time.

Implements Xapian::PostingSource.

Definition at line 851 of file api_postingsource.cc.

◆ init()

void EstimatePS::init ( const Xapian::Database & db )

inlineoverridevirtual

Set this PostingSource to the start of the list of postings.

This is called automatically by the matcher prior to each query being processed.

If a PostingSource is used for multiple searches, init() will therefore be called multiple times, and must handle this by using the database passed in the most recent call.

Parameters

db	The database which the PostingSource should iterate through.

Note: in the case of a multi-database search, a separate PostingSource will be used for each database (the separate PostingSources will be obtained using clone()), and each PostingSource will be passed one of the sub-databases as the db parameter here. The db parameter will therefore always refer to a single database. All docids passed to, or returned from, the PostingSource refer to docids in that single database, rather than in the multi-database.

Implements Xapian::PostingSource.

Definition at line 849 of file api_postingsource.cc.

◆ next()

void EstimatePS::next ( double min_wt )

inlineoverridevirtual

Advance the current position to the next matching document.

The PostingSource 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.

Xapian will always call init() on a PostingSource before calling this for the first time.

Parameters

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

Implements Xapian::PostingSource.

Definition at line 857 of file api_postingsource.cc.

References FAIL_TEST.

◆ skip_to()

void EstimatePS::skip_to	(	Xapian::docid	did,
		double	min_wt
	)

inlineoverridevirtual

Advance 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).

If the current position is already the specified docid, this method will leave the position unmodified.

If the specified docid is earlier than the current position, the behaviour is unspecified. A sensible behaviour would be to leave the current position unmodified, but it is also reasonable to move to the specified docid.

The default implementation calls next() repeatedly, which works but skip_to() can often be implemented much more efficiently.

Xapian will always call init() on a PostingSource before calling this for the first time.

Note: in the case of a multi-database search, the docid specified is the docid in the single subdatabase relevant to this posting source. See the init() method for details.

Parameters