xapian-core  1.4.21
Public Member Functions | Protected Member Functions | Protected Attributes | Private Member Functions | List of all members
SelectPostList Class Referenceabstract

A postlist parent class for classes which only return selected docs from a source postlist (e.g. More...

#include <selectpostlist.h>

+ Inheritance diagram for SelectPostList:
+ Collaboration diagram for SelectPostList:

Public Member Functions

PostListnext (double w_min)
 Advance the current position to the next document in the postlist. More...
 
PostListskip_to (Xapian::docid did, double w_min)
 Skip forward to the specified docid. More...
 
PostListcheck (Xapian::docid did, double w_min, bool &valid)
 Check if the specified docid occurs in this postlist. More...
 
Xapian::doccount get_termfreq_max () const
 Get an upper bound on the number of documents indexed by this term. More...
 
Xapian::doccount get_termfreq_min () const
 Get a lower bound on the number of documents indexed by this term. More...
 
double get_maxweight () const
 Return an upper bound on what get_weight() can return. More...
 
Xapian::docid get_docid () const
 Return the current docid. More...
 
double get_weight () const
 Return the weight contribution for the current position. 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...
 
double recalc_maxweight ()
 Recalculate the upper bound on what get_weight() can return. More...
 
PositionListread_position_list ()
 Read the position list for the term in the current document and return a pointer to it (owned by the PostList). More...
 
PositionListopen_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...
 
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...
 
 SelectPostList (PostList *source_)
 
 ~SelectPostList ()
 
- 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 Xapian::doccount get_termfreq_est () const =0
 Get an estimate of the number of documents indexed by this term. 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 Xapian::termcount get_wdf () const
 Return the wdf for the document at the current position. 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...
 
Internalnext ()
 Advance the current position to the next document in the postlist. More...
 
Internalskip_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...
 

Protected Member Functions

virtual bool test_doc ()=0
 Subclasses should override test_doc() with a method which returns true if a document meets the appropriate criterion, false in not. More...
 
- Protected Member Functions inherited from Xapian::PostingIterator::Internal
 Internal ()
 Only constructable as a base class for derived classes. More...
 

Protected Attributes

PostListsource
 
double wt
 

Private Member Functions

 SelectPostList (const SelectPostList &)
 
SelectPostListoperator= (const SelectPostList &)
 
bool check_weight (double w_min)
 

Additional Inherited Members

- Public Attributes inherited from Xapian::Internal::intrusive_base
unsigned _refs
 Reference count. More...
 

Detailed Description

A postlist parent class for classes which only return selected docs from a source postlist (e.g.

NEAR and PHRASE)

Definition at line 31 of file selectpostlist.h.

Constructor & Destructor Documentation

◆ SelectPostList() [1/2]

SelectPostList::SelectPostList ( const SelectPostList )
private

◆ SelectPostList() [2/2]

SelectPostList::SelectPostList ( PostList source_)
inlineexplicit

Definition at line 77 of file selectpostlist.h.

◆ ~SelectPostList()

SelectPostList::~SelectPostList ( )
inline

Definition at line 78 of file selectpostlist.h.

References source.

Member Function Documentation

◆ at_end()

bool SelectPostList::at_end ( ) const
inlinevirtual

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

Implements Xapian::PostingIterator::Internal.

Definition at line 69 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::at_end().

◆ check()

PostList * SelectPostList::check ( Xapian::docid  did,
double  w_min,
bool &  valid 
)
virtual

Check if the specified docid occurs in this postlist.

The caller is required to ensure that the specified docid actually exists in the database.

This method acts like skip_to() if that can be done at little extra cost, in which case it then sets valid to true.

Otherwise it simply checks if a particular docid is present. If it is, valid is set to true. If it isn't, it sets valid to false, and leaves the position unspecified (and hence the result of calling methods which depend on the current position, such as get_docid() and at_end(), are also unspecified). In this state, next() will advance to the first matching position after docid, and skip_to() will act as it would if the position was the first matching position after docid. If valid is set to false, then NULL must be returned (pruning in this situation doesn't make sense).

The default implementation calls skip_to().

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 62 of file selectpostlist.cc.

References Xapian::PostingIterator::Internal::at_end(), Xapian::PostingIterator::Internal::check(), check_weight(), LOGCALL, RETURN, source, test_doc(), and wt.

◆ check_weight()

bool SelectPostList::check_weight ( double  w_min)
inlineprivate

Definition at line 37 of file selectpostlist.h.

References get_weight().

Referenced by check(), next(), and skip_to().

◆ count_matching_subqs()

Xapian::termcount SelectPostList::count_matching_subqs ( ) const
inlinevirtual

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

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 71 of file selectpostlist.h.

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

◆ get_description()

std::string SelectPostList::get_description ( ) const
inlinevirtual

Return a string description of this object.

Implements Xapian::PostingIterator::Internal.

Definition at line 82 of file selectpostlist.h.

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

Referenced by count_matching_subqs().

◆ get_docid()

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

Return the current docid.

Implements Xapian::PostingIterator::Internal.

Definition at line 58 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::get_docid().

Referenced by skip_to().

◆ get_doclength()

Xapian::termcount SelectPostList::get_doclength ( ) const
inlinevirtual

Return the length of current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 64 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::get_doclength().

◆ get_maxweight()

double SelectPostList::get_maxweight ( ) const
inlinevirtual

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

Implements Xapian::PostingIterator::Internal.

Definition at line 57 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::get_maxweight().

◆ get_termfreq_max()

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

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

Implements Xapian::PostingIterator::Internal.

Definition at line 55 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::get_termfreq_max().

◆ get_termfreq_min()

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

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

Implements Xapian::PostingIterator::Internal.

Definition at line 56 of file selectpostlist.h.

◆ get_unique_terms()

Xapian::termcount SelectPostList::get_unique_terms ( ) const
inlinevirtual

Return the number of unique terms in the current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 65 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::get_unique_terms().

◆ get_weight()

double SelectPostList::get_weight ( ) const
inlinevirtual

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 59 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::get_weight(), and wt.

Referenced by check_weight().

◆ next()

PostList * SelectPostList::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_minThe 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 30 of file selectpostlist.cc.

References Xapian::PostingIterator::Internal::at_end(), check_weight(), LOGCALL, Xapian::PostingIterator::Internal::next(), RETURN, source, test_doc(), and wt.

◆ open_position_list()

PositionList* SelectPostList::open_position_list ( ) const
inlinevirtual

Read the position list for the term in the current document and return a pointer to it (not owned by the PostList).

The default implementation throws Xapian::UnimplementedError.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 68 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::open_position_list().

◆ operator=()

SelectPostList& SelectPostList::operator= ( const SelectPostList )
private

◆ read_position_list()

PositionList* SelectPostList::read_position_list ( )
inlinevirtual

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

The default implementation throws Xapian::UnimplementedError.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 67 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::read_position_list().

◆ recalc_maxweight()

double SelectPostList::recalc_maxweight ( )
inlinevirtual

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 66 of file selectpostlist.h.

References Xapian::PostingIterator::Internal::recalc_maxweight().

◆ skip_to()

PostList * SelectPostList::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_minThe 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 45 of file selectpostlist.cc.

References Xapian::PostingIterator::Internal::at_end(), check_weight(), get_docid(), LOGCALL, Xapian::PostingIterator::Internal::next(), RETURN, Xapian::PostingIterator::Internal::skip_to(), source, test_doc(), and wt.

Referenced by NearPostList::test_doc(), PhrasePostList::test_doc(), and ExactPhrasePostList::test_doc().

◆ test_doc()

virtual bool SelectPostList::test_doc ( )
protectedpure virtual

Subclasses should override test_doc() with a method which returns true if a document meets the appropriate criterion, false in not.

Implemented in ExactPhrasePostList, PhrasePostList, and NearPostList.

Referenced by check(), next(), and skip_to().

Member Data Documentation

◆ source

PostList* SelectPostList::source
protected

◆ wt

double SelectPostList::wt
mutableprotected

Definition at line 43 of file selectpostlist.h.

Referenced by check(), get_weight(), next(), and skip_to().


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