CLucene - a full-featured, c++ search engine
API Documentation
#include <Sort.h>
Public Member Functions | |
| ~Sort () | |
| Sort () | |
| Sorts by computed relevance. | |
| Sort (const TCHAR *field, bool reverse=false) | |
Sorts possibly in reverse by the terms in field then by index order (document number). | |
| Sort (const TCHAR **fields) | |
| Sorts in succession by the terms in each field. | |
| Sort (SortField *field) | |
| Sorts by the criteria in the given SortField. | |
| Sort (SortField **fields) | |
| Sorts in succession by the criteria in each SortField. | |
| void | setSort (const TCHAR *field, bool reverse=false) |
Sets the sort to the terms in field possibly in reverse, then by index order (document number). | |
| void | setSort (const TCHAR **fieldnames) |
| Sets the sort to the terms in each field in succession. | |
| void | setSort (SortField *field) |
| Sets the sort to the given criteria. | |
| void | setSort (SortField **fields) |
| Sets the sort to the given criteria in succession. | |
| TCHAR * | toString () const |
| SortField ** | getSort () const |
| Representation of the sort criteria. | |
Static Public Attributes | |
| static Sort * | RELEVANCE |
| Represents sorting by computed relevance. | |
| static Sort * | INDEXORDER |
| Represents sorting by index order. | |
The fields used to determine sort order must be carefully chosen. Documents must contain a single term in such a field, and the value of the term should indicate the document's relative position in a given sort order. The field must be indexed, but should not be tokenized, and does not need to be stored (unless you happen to want it back with the rest of your document data). In other words:
document.add (new Field ("byNumber", Integer.toString(x), false, true, false));
There are three possible kinds of term values which may be put into sorting fields: Integers, Floats, or Strings. Unless SortField objects are specified, the type of value in the field is determined by parsing the first term in the field.
Integer term values should contain only digits and an optional preceeding negative sign. Values must be base 10 and in the range Integer.MIN_VALUE and Integer.MAX_VALUE inclusive. Documents which should appear first in the sort should have low value integers, later documents high values (i.e. the documents should be numbered 1..n where 1 is the first and n the last).
Float term values should conform to values accepted by Float.valueOf(String) (except that NaN and Infinity are not supported). Documents which should appear first in the sort should have low values, later documents high values.
String term values can contain any valid String, but should not be tokenized. The values are sorted according to their natural order. Note that using this type of term value has higher memory requirements than the other two types.
One of these objects can be used multiple times and the sort order changed between usages.
This class is thread safe.
Sorting uses of caches of term values maintained by the internal HitQueue(s). The cache is static and contains an integer or float array of length IndexReader.maxDoc() for each field name for which a sort is performed. In other words, the size of the cache in bytes is:
4 * IndexReader.maxDoc() * (# of different fields actually used to sort)
For String fields, the cache is larger: in addition to the above array, the value of every term in the field is kept in memory. If there are many unique terms in the field, this could be quite large.
Note that the size of the cache is not affected by how many fields are in the index and might be used to sort - only by the ones actually used to sort a result set.
The cache is cleared each time a new IndexReader is passed in, or if the value returned by maxDoc() changes for the current IndexReader. This class is not set up to be able to efficiently sort hits from more than one index simultaneously.
| lucene::search::Sort::~Sort | ( | ) |
| lucene::search::Sort::Sort | ( | ) |
Sorts by computed relevance.
This is the same sort criteria as calling Searcher#search() without a sort criteria, only with slightly more overhead.
| lucene::search::Sort::Sort | ( | const TCHAR * | field, | |
| bool | reverse = false | |||
| ) |
| lucene::search::Sort::Sort | ( | const TCHAR ** | fields | ) |
Sorts in succession by the terms in each field.
The type of value in field is determined automatically.
| lucene::search::Sort::Sort | ( | SortField ** | fields | ) |
Sorts in succession by the criteria in each SortField.
| void lucene::search::Sort::setSort | ( | const TCHAR * | field, | |
| bool | reverse = false | |||
| ) |
| void lucene::search::Sort::setSort | ( | const TCHAR ** | fieldnames | ) |
Sets the sort to the terms in each field in succession.
| void lucene::search::Sort::setSort | ( | SortField * | field | ) |
Sets the sort to the given criteria.
| void lucene::search::Sort::setSort | ( | SortField ** | fields | ) |
Sets the sort to the given criteria in succession.
| TCHAR* lucene::search::Sort::toString | ( | ) | const |
| SortField** lucene::search::Sort::getSort | ( | ) | const [inline] |
Representation of the sort criteria.
Sort* lucene::search::Sort::RELEVANCE [static] |
Represents sorting by computed relevance.
Using this sort criteria returns the same results as calling Searcher#search() without a sort criteria, only with slightly more overhead.
Sort* lucene::search::Sort::INDEXORDER [static] |
Represents sorting by index order.