Lucene++ - a full-featured, c++ search engine
API Documentation
Encapsulates sort criteria for returned hits. More...
#include <Sort.h>
Public Member Functions | |
Sort () | |
Sorts by computed relevance. This is the same sort criteria as calling Searcher#search() without a sort criteria, only with slightly more overhead. | |
Sort (const SortFieldPtr &field) | |
Sorts by the criteria in the given SortField. | |
Sort (Collection< SortFieldPtr > fields) | |
Sorts in succession by the criteria in each SortField. | |
virtual | ~Sort () |
virtual String | getClassName () |
boost::shared_ptr< Sort > | shared_from_this () |
void | setSort (const SortFieldPtr &field) |
Sets the sort to the given criteria. | |
void | setSort (Collection< SortFieldPtr > fields) |
Sets the sort to the given criteria in succession. | |
Collection< SortFieldPtr > | getSort () |
Representation of the sort criteria. | |
virtual String | toString () |
Returns a string representation of the object. | |
virtual bool | equals (const LuceneObjectPtr &other) |
Return whether two objects are equal. | |
virtual int32_t | hashCode () |
Return hash code for this object. | |
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virtual | ~LuceneObject () |
virtual void | initialize () |
Called directly after instantiation to create objects that depend on this object being fully constructed. | |
virtual LuceneObjectPtr | clone (const LuceneObjectPtr &other=LuceneObjectPtr()) |
Return clone of this object. | |
virtual int32_t | compareTo (const LuceneObjectPtr &other) |
Compare two objects. | |
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virtual | ~LuceneSync () |
virtual SynchronizePtr | getSync () |
Return this object synchronize lock. | |
virtual LuceneSignalPtr | getSignal () |
Return this object signal. | |
virtual void | lock (int32_t timeout=0) |
Lock this object using an optional timeout. | |
virtual void | unlock () |
Unlock this object. | |
virtual bool | holdsLock () |
Returns true if this object is currently locked by current thread. | |
virtual void | wait (int32_t timeout=0) |
Wait for signal using an optional timeout. | |
virtual void | notifyAll () |
Notify all threads waiting for signal. | |
Static Public Member Functions | |
static String | _getClassName () |
static SortPtr | RELEVANCE () |
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. | |
static SortPtr | INDEXORDER () |
Represents sorting by index order. | |
Data Fields | |
Collection< SortFieldPtr > | fields |
Internal representation of the sort criteria. | |
Additional Inherited Members | |
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LuceneObject () | |
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SynchronizePtr | objectLock |
LuceneSignalPtr | objectSignal |
Encapsulates sort criteria for returned hits.
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(newLucene<Field>(L"byNumber", StringUtils::toString(x), Field::STORE_NO, Field::INDEX_NOT_ANALYZED));
Valid Types of Values
There are four possible kinds of term values which may be put into sorting fields: Integers, Longs, Doubles, 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 preceding negative sign. Values must be base 10 and in the range INT_MIN and INT_MAX inclusive. Documents which should appear first in the sort should have low value integers, later documents high values (ie. the documents should be numbered 1..n where 1 is the first and n the last).
Long term values should contain only digits and an optional preceding negative sign. Values must be base 10 and in the range LLONG_MIN and LLONG_MAX inclusive. Documents which should appear first in the sort should have low value integers, later documents high values.
Double term values should conform to values accepted by Double (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 comparable natural order. Note that using this type of term value has higher memory requirements than the other two types.
Object Reuse
One of these objects can be used multiple times and the sort order changed between usages. This class is thread safe.
Memory Usage
Sorting uses of caches of term values maintained by the internal HitQueue(s). The cache is static and contains an integer or double 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.
Lucene::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::Sort::Sort | ( | const SortFieldPtr & | field | ) |
Sorts by the criteria in the given SortField.
Lucene::Sort::Sort | ( | Collection< SortFieldPtr > | fields | ) |
Sorts in succession by the criteria in each SortField.
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virtual |
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inlinestatic |
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virtual |
Return whether two objects are equal.
Reimplemented from Lucene::LuceneObject.
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inlinevirtual |
Collection< SortFieldPtr > Lucene::Sort::getSort | ( | ) |
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virtual |
Return hash code for this object.
Reimplemented from Lucene::LuceneObject.
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static |
Represents sorting by index order.
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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.
void Lucene::Sort::setSort | ( | Collection< SortFieldPtr > | fields | ) |
Sets the sort to the given criteria in succession.
void Lucene::Sort::setSort | ( | const SortFieldPtr & | field | ) |
Sets the sort to the given criteria.
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inline |
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virtual |
Returns a string representation of the object.
Reimplemented from Lucene::LuceneObject.
Collection<SortFieldPtr> Lucene::Sort::fields |
Internal representation of the sort criteria.