Xapian::MSet Class Reference

A match set (MSet). More...

List of all members.

Public Types

typedef MSetIterator value_type
 Allow use as an STL container.
typedef MSetIterator iterator
 Allow use as an STL container.
typedef MSetIterator const_iterator
 Allow use as an STL container.
typedef MSetIteratorreference
 Allow use as an STL container.
typedef MSetIteratorconst_reference
 Allow use as an STL container.
typedef MSetIteratorpointer
 Allow use as an STL container.
typedef Xapian::doccount_diff difference_type
 Allow use as an STL container.
typedef Xapian::doccount size_type
 Allow use as an STL container.

Public Member Functions

 MSet ()
 Create an empty Xapian::MSet.
 ~MSet ()
 Destroy a Xapian::MSet.
 MSet (const MSet &other)
 Copying is allowed (and is cheap).
void operator= (const MSet &other)
 Assignment is allowed (and is cheap).
void fetch (const MSetIterator &begin, const MSetIterator &end) const
 Fetch the document info for a set of items in the MSet.
void fetch (const MSetIterator &item) const
 Fetch the single item specified.
void fetch () const
 Fetch all the items in the MSet.
Xapian::percent convert_to_percent (Xapian::weight wt) const
 This converts the weight supplied to a percentage score.
Xapian::percent convert_to_percent (const MSetIterator &it) const
 Return the percentage score for a particular item.
Xapian::doccount get_termfreq (const std::string &tname) const
 Return the term frequency of the given query term.
Xapian::weight get_termweight (const std::string &tname) const
 Return the term weight of the given query term.
Xapian::doccount get_firstitem () const
 The index of the first item in the result which was put into the MSet.
Xapian::doccount get_matches_lower_bound () const
 A lower bound on the number of documents in the database which match the query.
Xapian::doccount get_matches_estimated () const
 An estimate for the number of documents in the database which match the query.
Xapian::doccount get_matches_upper_bound () const
 An upper bound on the number of documents in the database which match the query.
Xapian::doccount get_uncollapsed_matches_lower_bound () const
 A lower bound on the number of documents in the database which would match the query if collapsing wasn't used.
Xapian::doccount get_uncollapsed_matches_estimated () const
 A estimate of the number of documents in the database which would match the query if collapsing wasn't used.
Xapian::doccount get_uncollapsed_matches_upper_bound () const
 A upper bound on the number of documents in the database which would match the query if collapsing wasn't used.
Xapian::weight get_max_possible () const
 The maximum possible weight in the MSet.
Xapian::weight get_max_attained () const
 The greatest weight which is attained by any document in the database.
Xapian::doccount size () const
 The number of items in this MSet.
Xapian::doccount max_size () const
 Required to allow use as an STL container.
bool empty () const
 Test if this MSet is empty.
void swap (MSet &other)
 Swap the MSet we point to with another.
MSetIterator begin () const
 Iterator for the items in this MSet.
MSetIterator end () const
 End iterator corresponding to begin().
MSetIterator back () const
 Iterator pointing to the last element of this MSet.
MSetIterator operator[] (Xapian::doccount i) const
 This returns the document at position i in this MSet object.
std::string get_description () const
 Return a string describing this object.


Detailed Description

A match set (MSet).

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


Member Function Documentation

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.

Parameters:
wt The weight to convert.

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

Fetch 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.

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 match the query.

This figure takes into account collapsing of duplicates, and weighting cutoff values.

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 match the query.

This figure takes into account collapsing of duplicates, and weighting cutoff values.

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 which match the query.

This figure takes into account collapsing of duplicates, and weighting cutoff values.

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 and the primary ordering is by relevance, this is the weight of the first entry in the MSet.

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.
This is sometimes more efficient than asking the database directly for the term frequency - in particular, if the term was in the query, its frequency will usually be cached in the MSet.

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.

Xapian::doccount Xapian::MSet::max_size (  )  const [inline]

Required to allow use as an STL container.

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.

Parameters:
i The index into the MSet.


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

Documentation for Xapian (version 1.2.15).
Generated on 17 Apr 2013 by Doxygen 1.5.9.