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WordCursor is an iterator on an inverted index. It is created by
asking a
WordList
object with the
Cursor.
There is
no other way to create a WordCursor object.
When the
Walk*
methods return,
the WordCursor object contains the result of the search and
status information that indicates if it reached the end of
the list (IsAtEnd() method).
The callback function that is called each time a match is found takes the following arguments:
WordList* words pointer to the inverted index handle. WordDBCursor& cursor to call Del() and delete the current match WordReference* wordRef is the match Object& data is the user data provided by the caller when search began.
The
WordKey
object that specifies the search criterion
may be used as follows (assuming word is followed by DOCID and
LOCATION):
Ex1: WordKey() walk the entire list of occurences.
Ex2:
WordKey("word <UNDEF> <UNDEF>")
find all occurrences
of
word
.
Ex3:
WordKey("meet <UNDEF> 1")
find all occurrences of
meet
that occur at LOCATION 1 in any DOCID. This can
be inefficient since the search has to scan all occurrences
of
meet
to find the ones that occur at LOCATION 1.
Ex4:
WordKey("meet 2 <UNDEF>")
find all occurrences of
meet
that occur in DOCID 2, at any location.
WordList is an abstract class and cannot be instanciated. See the WordCursorOne manual page for an actual implementation of a WordCursor object.