xapian-core  1.4.20
Public Member Functions | Private Attributes | List of all members
ChangeMaxweightPostingSource Class Reference
+ Inheritance diagram for ChangeMaxweightPostingSource:
+ Collaboration diagram for ChangeMaxweightPostingSource:

Public Member Functions

 ChangeMaxweightPostingSource (Xapian::docid maxid_accessed_)
 
void init (const Xapian::Database &)
 Set this PostingSource to the start of the list of postings. More...
 
double get_weight () const
 Return the weight contribution for the current document. More...
 
Xapian::doccount get_termfreq_min () const
 A lower bound on the number of documents this object can return. More...
 
Xapian::doccount get_termfreq_est () const
 An estimate of the number of documents this object can return. More...
 
Xapian::doccount get_termfreq_max () const
 An upper bound on the number of documents this object can return. More...
 
void next (double)
 Advance the current position to the next matching document. More...
 
void skip_to (Xapian::docid to_did, double)
 Advance to the specified docid. More...
 
bool at_end () const
 Return true if the current position is past the last entry in this list. More...
 
Xapian::docid get_docid () const
 Return the current docid. More...
 
string get_description () const
 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 bool check (Xapian::docid did, double min_wt)
 Check if the specified docid occurs. More...
 
virtual PostingSourceclone () const
 Clone the posting source. 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 PostingSourceunserialise (const std::string &serialised) const
 Create object given string serialisation returned by serialise(). More...
 
virtual PostingSourceunserialise_with_registry (const std::string &serialised, const Registry &registry) const
 Create object given string serialisation returned by serialise(). More...
 
PostingSourcerelease ()
 Start reference counting this object. More...
 
const PostingSourcerelease () 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_baseoperator= (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::docid did
 
Xapian::docid maxid_accessed
 

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

Definition at line 449 of file api_postingsource.cc.

Constructor & Destructor Documentation

◆ ChangeMaxweightPostingSource()

ChangeMaxweightPostingSource::ChangeMaxweightPostingSource ( Xapian::docid  maxid_accessed_)
inline

Definition at line 456 of file api_postingsource.cc.

Member Function Documentation

◆ at_end()

bool ChangeMaxweightPostingSource::at_end ( ) const
inlinevirtual

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 484 of file api_postingsource.cc.

Referenced by DEFINE_TESTCASE().

◆ get_description()

string ChangeMaxweightPostingSource::get_description ( ) const
inlinevirtual

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 486 of file api_postingsource.cc.

◆ get_docid()

Xapian::docid ChangeMaxweightPostingSource::get_docid ( ) const
inlinevirtual

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 485 of file api_postingsource.cc.

Referenced by DEFINE_TESTCASE().

◆ get_termfreq_est()

Xapian::doccount ChangeMaxweightPostingSource::get_termfreq_est ( ) const
inlinevirtual

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 471 of file api_postingsource.cc.

◆ get_termfreq_max()

Xapian::doccount ChangeMaxweightPostingSource::get_termfreq_max ( ) const
inlinevirtual

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 472 of file api_postingsource.cc.

◆ get_termfreq_min()

Xapian::doccount ChangeMaxweightPostingSource::get_termfreq_min ( ) const
inlinevirtual

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 470 of file api_postingsource.cc.

◆ get_weight()

double ChangeMaxweightPostingSource::get_weight ( ) const
inlinevirtual

Return the weight contribution for the current document.

This default implementation always returns 0, for convenience when implementing "weight-less" PostingSource subclasses.

This method may assume that it will only be called when there is a "current document". In detail: Xapian will always call init() on a PostingSource before calling this for the first time. It will also only call this if the PostingSource reports that it is pointing to a valid document (ie, it will not call it before calling at least one of next(), skip_to() or check(), and will ensure that the PostingSource is not at the end by calling at_end()).

Reimplemented from Xapian::PostingSource.

Definition at line 461 of file api_postingsource.cc.

References FAIL_TEST, and Xapian::Internal::str().

◆ init()

void ChangeMaxweightPostingSource::init ( const Xapian::Database db)
inlinevirtual

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
dbThe 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 459 of file api_postingsource.cc.

◆ next()

void ChangeMaxweightPostingSource::next ( double  min_wt)
inlinevirtual

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

Implements Xapian::PostingSource.

Definition at line 474 of file api_postingsource.cc.

◆ skip_to()

void ChangeMaxweightPostingSource::skip_to ( Xapian::docid  did,
double  min_wt 
)
inlinevirtual

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
didThe document id to advance to.
min_wtThe minimum weight contribution that is needed (this is just a hint which subclasses may ignore).

Reimplemented from Xapian::PostingSource.

Definition at line 479 of file api_postingsource.cc.

Member Data Documentation

◆ did

Xapian::docid ChangeMaxweightPostingSource::did
private

Definition at line 450 of file api_postingsource.cc.

◆ maxid_accessed

Xapian::docid ChangeMaxweightPostingSource::maxid_accessed
private

Definition at line 453 of file api_postingsource.cc.


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