ChangeMaxweightPostingSource Class Reference
Public Member Functions | |
| ChangeMaxweightPostingSource (Xapian::docid maxid_accessed_) | |
| void | init (const Xapian::Database &) |
| Set this PostingSource to the start of the list of postings. | |
| Xapian::weight | get_weight () const |
| Return the weight contribution for the current document. | |
| Xapian::doccount | get_termfreq_min () const |
| A lower bound on the number of documents this object can return. | |
| Xapian::doccount | get_termfreq_est () const |
| An estimate of the number of documents this object can return. | |
| Xapian::doccount | get_termfreq_max () const |
| An upper bound on the number of documents this object can return. | |
| void | next (Xapian::weight) |
| Advance the current position to the next matching document. | |
| void | skip_to (Xapian::docid to_did, Xapian::weight) |
| Advance to the specified docid. | |
| bool | at_end () const |
| Return true if the current position is past the last entry in this list. | |
| Xapian::docid | get_docid () const |
| Return the current docid. | |
| string | get_description () const |
| Return a string describing this object. | |
Private Attributes | |
| Xapian::docid | did |
| Xapian::docid | maxid_accessed |
Detailed Description
Definition at line 464 of file api_postingsource.cc.
Constructor & Destructor Documentation
| ChangeMaxweightPostingSource::ChangeMaxweightPostingSource | ( | Xapian::docid | maxid_accessed_ | ) | [inline] |
Definition at line 471 of file api_postingsource.cc.
Member Function Documentation
| bool ChangeMaxweightPostingSource::at_end | ( | ) | const [inline, virtual] |
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 499 of file api_postingsource.cc.
References did.
Referenced by DEFINE_TESTCASE().
| string ChangeMaxweightPostingSource::get_description | ( | ) | const [inline, virtual] |
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 501 of file api_postingsource.cc.
| Xapian::docid ChangeMaxweightPostingSource::get_docid | ( | ) | const [inline, virtual] |
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 500 of file api_postingsource.cc.
References did.
Referenced by DEFINE_TESTCASE().
| Xapian::doccount ChangeMaxweightPostingSource::get_termfreq_est | ( | ) | const [inline, virtual] |
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 486 of file api_postingsource.cc.
| Xapian::doccount ChangeMaxweightPostingSource::get_termfreq_max | ( | ) | const [inline, virtual] |
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 487 of file api_postingsource.cc.
| Xapian::doccount ChangeMaxweightPostingSource::get_termfreq_min | ( | ) | const [inline, virtual] |
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 485 of file api_postingsource.cc.
| Xapian::weight ChangeMaxweightPostingSource::get_weight | ( | ) | const [inline, virtual] |
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 476 of file api_postingsource.cc.
References did, FAIL_TEST, maxid_accessed, and Xapian::Internal::str().
| void ChangeMaxweightPostingSource::init | ( | const Xapian::Database & | db | ) | [inline, virtual] |
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:
-
db The 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 474 of file api_postingsource.cc.
References did.
| void ChangeMaxweightPostingSource::next | ( | Xapian::weight | min_wt | ) | [inline, virtual] |
Advance the current position to the next matching document.
The PostingSource starts before the first entry in the list, so next() 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_wt The minimum weight contribution that is needed (this is just a hint which subclasses may ignore).
Implements Xapian::PostingSource.
Definition at line 489 of file api_postingsource.cc.
References did, and Xapian::PostingSource::set_maxweight().
| void ChangeMaxweightPostingSource::skip_to | ( | Xapian::docid | did, | |
| Xapian::weight | min_wt | |||
| ) | [inline, virtual] |
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:
-
did The document id to advance to. min_wt The minimum weight contribution that is needed (this is just a hint which subclasses may ignore).
Reimplemented from Xapian::PostingSource.
Definition at line 494 of file api_postingsource.cc.
References did, and Xapian::PostingSource::set_maxweight().
Member Data Documentation
Definition at line 465 of file api_postingsource.cc.
Referenced by at_end(), get_docid(), get_weight(), init(), next(), and skip_to().
The documentation for this class was generated from the following file:
- tests/api_postingsource.cc