ExceptionalPostingSource Class Reference
Public Types | |
| enum | failmode { NONE, CLONE, DTOR } |
Public Member Functions | |
| ExceptionalPostingSource (failmode fail_, PostingSource *&allocated_) | |
| ~ExceptionalPostingSource () | |
| string | name () const |
| Name of the posting source class. | |
| PostingSource * | clone () const |
| Clone the posting source. | |
| void | init (const Xapian::Database &) |
| Set this PostingSource to the start of the list of postings. | |
| 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, 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. | |
Public Attributes | |
| failmode | fail |
| PostingSource *& | allocated |
Detailed Description
Definition at line 306 of file api_serialise.cc.
Member Enumeration Documentation
Constructor & Destructor Documentation
| ExceptionalPostingSource::ExceptionalPostingSource | ( | failmode | fail_, | |
| PostingSource *& | allocated_ | |||
| ) | [inline] |
| ExceptionalPostingSource::~ExceptionalPostingSource | ( | ) | [inline] |
Member Function Documentation
| bool ExceptionalPostingSource::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 344 of file api_serialise.cc.
| PostingSource* ExceptionalPostingSource::clone | ( | ) | const [inline, virtual] |
Clone the posting source.
The clone should inherit the configuration of the parent, but need not inherit the state. ie, the clone does not need to be in the same iteration position as the original: the matcher will always call init() on the clone before attempting to move the iterator, or read the information about the current position of the iterator.
This may return NULL to indicate that cloning is not supported. In this case, the PostingSource may only be used with a single-database search.
The default implementation returns NULL.
Note that the returned object will be deallocated by Xapian after use with "delete". If you want to handle the deletion in a special way (for example when wrapping the Xapian API for use from another language) then you can define a static operator delete method in your subclass as shown here: http://trac.xapian.org/ticket/554#comment:1
Reimplemented from Xapian::PostingSource.
Definition at line 327 of file api_serialise.cc.
References allocated, CLONE, ExceptionalPostingSource(), and fail.
| Xapian::docid ExceptionalPostingSource::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 345 of file api_serialise.cc.
| Xapian::doccount ExceptionalPostingSource::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 337 of file api_serialise.cc.
| Xapian::doccount ExceptionalPostingSource::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 338 of file api_serialise.cc.
| Xapian::doccount ExceptionalPostingSource::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 336 of file api_serialise.cc.
| void ExceptionalPostingSource::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 334 of file api_serialise.cc.
| string ExceptionalPostingSource::name | ( | ) | const [inline, virtual] |
Name of the posting source class.
This is used when serialising and unserialising posting sources; for example, for performing remote searches.
If the subclass is in a C++ namespace, the namespace should be included in the name, using "::" as a separator. For example, for a PostingSource subclass called "FooPostingSource" in the "Xapian" namespace the result of this call should be "Xapian::FooPostingSource".
This should only be implemented if serialise() and unserialise() are also implemented. The default implementation returns an empty string.
If this returns an empty string, Xapian will assume that serialise() and unserialise() are not implemented.
Reimplemented from Xapian::PostingSource.
Definition at line 323 of file api_serialise.cc.
| void ExceptionalPostingSource::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 340 of file api_serialise.cc.
| void ExceptionalPostingSource::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 342 of file api_serialise.cc.
Member Data Documentation
| PostingSource* & ExceptionalPostingSource::allocated |
Definition at line 310 of file api_serialise.cc.
Referenced by clone(), DEFINE_TESTCASE(), and ~ExceptionalPostingSource().
The documentation for this class was generated from the following file:
- tests/api_serialise.cc