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Xapian::MSet Class Reference

A match set (MSet). More...

#include <enquire.h>

List of all members.

Public Types

typedef MSetIterator value_type
typedef MSetIterator iterator
typedef MSetIterator const_iterator
typedef MSetIteratorreference
typedef MSetIteratorconst_reference
typedef MSetIteratorpointer
typedef Xapian::doccount_diff difference_type
typedef Xapian::doccount size_type

Public Methods

 MSet (MSet::Internal *internal_)
 MSet ()
 Create an empty Xapian::MSet. More...

 ~MSet ()
 Destroy an Xapian::MSet. More...

 MSet (const MSet &other)
 Copying is allowed (and is cheap). More...

void operator= (const MSet &other)
 Assignment is allowed (and is cheap). More...

void fetch (const MSetIterator &begin, const MSetIterator &end) const
 Fetch the the document info for a set of items in the MSet. More...

void fetch (const MSetIterator &item) const
 Fetch the single item specified. More...

void fetch () const
 Fetch all the items in the MSet. More...

Xapian::percent convert_to_percent (Xapian::weight wt) const
 This converts the weight supplied to a percentage score. More...

Xapian::percent convert_to_percent (const MSetIterator &it) const
 Return the percentage score for a particular item. More...

Xapian::doccount get_termfreq (const std::string &tname) const
 Return the term frequency of the given query term. More...

Xapian::weight get_termweight (const std::string &tname) const
 Return the term weight of the given query term. More...

Xapian::doccount get_firstitem () const
 The index of the first item in the result which was put into the MSet. More...

Xapian::doccount get_matches_lower_bound () const
 A lower bound on the number of documents in the database which have a weight greater than zero. More...

Xapian::doccount get_matches_estimated () const
 An estimate for the number of documents in the database which have a weight greater than zero. More...

Xapian::doccount get_matches_upper_bound () const
 An upper bound on the number of documents in the database with a weight greater than zero. More...

Xapian::weight get_max_possible () const
 The maximum possible weight in the mset. More...

Xapian::weight get_max_attained () const
 The greatest weight which is attained by any document in the database. More...

Xapian::doccount size () const
Xapian::doccount max_size () const
bool empty () const
void swap (MSet &other)
MSetIterator begin () const
MSetIterator end () const
MSetIterator back () const
MSetIterator operator[] (Xapian::doccount i) const
 This returns the document at position i in this MSet object. More...

std::string get_description () const
 Returns a string representing the mset. More...


Public Attributes

Xapian::Internal::RefCntPtr<
Internal > 
internal


Detailed Description

A match set (MSet).

This class represents (a portion of) the results of a query.


Constructor & Destructor Documentation

Xapian::MSet::MSet  
 

Create an empty Xapian::MSet.

Xapian::MSet::~MSet  
 

Destroy an Xapian::MSet.

Xapian::MSet::MSet const MSet &    other
 

Copying is allowed (and is cheap).


Member Function Documentation

Xapian::percent Xapian::MSet::convert_to_percent const MSetIterator   it const
 

Return the percentage score for a particular item.

Xapian::percent Xapian::MSet::convert_to_percent Xapian::weight    wt const
 

This converts the weight supplied to a percentage score.

The return value will be in the range 0 to 100, and will be 0 if and only if the item did not match the query at all.

void Xapian::MSet::fetch   const
 

Fetch all the items in the MSet.

void Xapian::MSet::fetch const MSetIterator   item const
 

Fetch the single item specified.

void Xapian::MSet::fetch const MSetIterator   begin,
const MSetIterator   end
const
 

Fetch the the document info for a set of items in the MSet.

This method causes the documents in the range specified by the iterators to be fetched from the database, and cached in the Xapian::MSet object. This has little effect when performing a search across a local database, but will greatly speed up subsequent access to the document contents when the documents are stored in a remote database.

The iterators must be over this Xapian::MSet: undefined behaviour will result otherwise.

Parameters:
begin  MSetIterator for first item to fetch.
end  MSetIterator for item after last item to fetch.

std::string Xapian::MSet::get_description   const
 

Returns a string representing the mset.

Introspection method.

Xapian::doccount Xapian::MSet::get_firstitem   const
 

The index of the first item in the result which was put into the MSet.

This corresponds to the parameter "first" specified in Xapian::Enquire::get_mset(). A value of 0 corresponds to the highest result being the first item in the mset.

Xapian::doccount Xapian::MSet::get_matches_estimated   const
 

An estimate for the number of documents in the database which have a weight greater than zero.

This value is returned because there is sometimes a request to display such information. However, our experience is that presenting this value to users causes them to worry about the large number of results, rather than how useful those at the top of the result set are, and is thus undesirable.

Xapian::doccount Xapian::MSet::get_matches_lower_bound   const
 

A lower bound on the number of documents in the database which have a weight greater than zero.

This number is usually considerably less than the actual number of documents which match the query.

Xapian::doccount Xapian::MSet::get_matches_upper_bound   const
 

An upper bound on the number of documents in the database with a weight greater than zero.

This number is usually considerably greater than the actual number of documents which match the query.

Xapian::weight Xapian::MSet::get_max_attained   const
 

The greatest weight which is attained by any document in the database.

If firstitem == 0, this is the weight of the first entry in items.

If no documents are found by the query, this will be 0.

Note that calculation of max_attained requires calculation of at least one result item - therefore, if no items were requested when the query was performed (by specifying maxitems = 0 in Xapian::Enquire::get_mset()), this value will be 0.

Xapian::weight Xapian::MSet::get_max_possible   const
 

The maximum possible weight in the mset.

This weight is likely not to be attained in the set of results, but represents an upper bound on the weight which a document could attain for the given query.

Xapian::doccount Xapian::MSet::get_termfreq const std::string &    tname const
 

Return the term frequency of the given query term.

Parameters:
tname  The term to look for.
Exceptions:
Xapian::InvalidArgumentError  is thrown if the term was not in the query.

Xapian::weight Xapian::MSet::get_termweight const std::string &    tname const
 

Return the term weight of the given query term.

Parameters:
tname  The term to look for.
Exceptions:
Xapian::InvalidArgumentError  is thrown if the term was not in the query.

void Xapian::MSet::operator= const MSet &    other
 

Assignment is allowed (and is cheap).

MSetIterator Xapian::MSet::operator[] Xapian::doccount    i const
 

This returns the document at position i in this MSet object.

Note that this is not the same as the document at rank i in the query, unless the "first" parameter to Xapian::Enquire::get_mset was 0. Rather, it is the document at rank i + first.

In other words, the offset is into the documents represented by this object, not into the set of documents matching the query.


The documentation for this class was generated from the following file:
Documentation for Xapian (version 0.6.5).
Generated on 4 Jul 2003 by Doxygen 1.2.15.