xapian-core  1.4.21
Public Member Functions | Private Member Functions | List of all members
EmptyPostList Class Reference

A PostList which contains no entries. More...

#include <emptypostlist.h>

+ Inheritance diagram for EmptyPostList:
+ Collaboration diagram for EmptyPostList:

Public Member Functions

 EmptyPostList ()
 Constructor. 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_max () const
 Get an upper 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...
 
TermFreqs get_termfreq_est_using_stats (const Xapian::Weight::Internal &) const
 Get an estimate for the termfreq and reltermfreq, given the stats. 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...
 
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 get_weight () 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...
 
PostListnext (double w_min)
 Advance the current position to the next document in the postlist. More...
 
PostListskip_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...
 
- 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::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...
 
virtual 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...
 
virtual 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...
 
virtual Internalcheck (Xapian::docid did, double w_min, bool &valid)
 Check if the specified docid occurs in this postlist. 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 Xapian::termcount count_matching_subqs () const
 Count the number of leaf subqueries which match at the current position. 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 Member Functions

void operator= (const EmptyPostList &)
 Don't allow assignment. More...
 
 EmptyPostList (const EmptyPostList &)
 Don't allow copying. 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 which contains no entries.

Definition at line 27 of file emptypostlist.h.

Constructor & Destructor Documentation

◆ EmptyPostList() [1/2]

EmptyPostList::EmptyPostList ( const EmptyPostList )
private

Don't allow copying.

◆ EmptyPostList() [2/2]

EmptyPostList::EmptyPostList ( )
inline

Member Function Documentation

◆ at_end()

bool EmptyPostList::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 88 of file emptypostlist.cc.

Referenced by EmptyPostList().

◆ get_description()

string EmptyPostList::get_description ( ) const
virtual

Return a string description of this object.

Implements Xapian::PostingIterator::Internal.

Definition at line 112 of file emptypostlist.cc.

Referenced by EmptyPostList().

◆ get_docid()

Xapian::docid EmptyPostList::get_docid ( ) const
virtual

Return the current docid.

Implements Xapian::PostingIterator::Internal.

Definition at line 62 of file emptypostlist.cc.

References Assert.

Referenced by EmptyPostList(), get_doclength(), and get_unique_terms().

◆ get_doclength()

Xapian::termcount EmptyPostList::get_doclength ( ) const
virtual

Return the length of current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 69 of file emptypostlist.cc.

References get_docid().

Referenced by EmptyPostList().

◆ get_maxweight()

double EmptyPostList::get_maxweight ( ) const
virtual

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

Implements Xapian::PostingIterator::Internal.

Definition at line 56 of file emptypostlist.cc.

Referenced by EmptyPostList(), and recalc_maxweight().

◆ get_termfreq_est()

Xapian::doccount EmptyPostList::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 42 of file emptypostlist.cc.

Referenced by EmptyPostList().

◆ get_termfreq_est_using_stats()

TermFreqs EmptyPostList::get_termfreq_est_using_stats ( const Xapian::Weight::Internal stats) const
virtual

Get an estimate for the termfreq and reltermfreq, given the stats.

The frequencies may be for a combination of databases, or for just the relevant documents, so the results need not lie in the bounds given by get_termfreq_min() and get_termfreq_max().

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 50 of file emptypostlist.cc.

Referenced by EmptyPostList().

◆ get_termfreq_max()

Xapian::doccount EmptyPostList::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 36 of file emptypostlist.cc.

Referenced by EmptyPostList().

◆ get_termfreq_min()

Xapian::doccount EmptyPostList::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 30 of file emptypostlist.cc.

Referenced by EmptyPostList().

◆ get_unique_terms()

Xapian::termcount EmptyPostList::get_unique_terms ( ) const
virtual

Return the number of unique terms in the current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 75 of file emptypostlist.cc.

References get_docid().

Referenced by EmptyPostList().

◆ get_weight()

double EmptyPostList::get_weight ( ) const
virtual

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 81 of file emptypostlist.cc.

References Assert.

Referenced by EmptyPostList().

◆ next()

PostList * EmptyPostList::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 100 of file emptypostlist.cc.

◆ operator=()

void EmptyPostList::operator= ( const EmptyPostList )
private

Don't allow assignment.

◆ recalc_maxweight()

double EmptyPostList::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 94 of file emptypostlist.cc.

References get_maxweight().

Referenced by EmptyPostList().

◆ skip_to()

PostList * EmptyPostList::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 106 of file emptypostlist.cc.

Referenced by EmptyPostList().


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