org.apache.lucene.queries.function

Class ValueSource

java.lang.Object

org.apache.lucene.queries.function.ValueSource

Direct Known Subclasses:

BoolFunction, ConstNumberSource, DocFreqValueSource, DualFloatFunction, FieldCacheSource, LinearFloatFunction, LiteralValueSource, MaxDocValueSource, MultiFloatFunction, MultiFunction, MultiValueSource, NormValueSource, NumDocsValueSource, QueryValueSource, RangeMapFloatFunction, ReciprocalFloatFunction, ScaleFloatFunction, SingleFunction, SumTotalTermFreqValueSource, TotalTermFreqValueSource

public abstract class ValueSource
extends Object

Instantiates FunctionValues for a particular reader.
Often used when creating a FunctionQuery.

Constructor Summary

Constructors

Constructor and Description
ValueSource()

Method Summary

Modifier and Type	Method and Description
DoubleValuesSource	asDoubleValuesSource() Expose this ValueSource as a DoubleValuesSource
LongValuesSource	asLongValuesSource() Expose this ValueSource as a LongValuesSource
void	createWeight(Map context, IndexSearcher searcher) Implementations should propagate createWeight to sub-ValueSources which can optionally store weight info in the context.
abstract String	description() description of field, used in explain()
abstract boolean	equals(Object o)
static ValueSource	fromDoubleValuesSource(DoubleValuesSource in)
SortField	getSortField(boolean reverse) EXPERIMENTAL: This method is subject to change.
abstract FunctionValues	getValues(Map context, LeafReaderContext readerContext) Gets the values for this reader and the context that was previously passed to createWeight().
abstract int	hashCode()
static Map	newContext(IndexSearcher searcher) Returns a new non-threadsafe context map.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ValueSource

public ValueSource()

Method Detail

getValues

public abstract FunctionValues getValues(Map context,
                                         LeafReaderContext readerContext)
                                  throws IOException

Gets the values for this reader and the context that was previously passed to createWeight(). The values must be consumed in a forward docID manner, and you must call this method again to iterate through the values again.

Throws:

IOException

equals

public abstract boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public abstract int hashCode()

Overrides:

hashCode in class Object

description

public abstract String description()

description of field, used in explain()

toString

public String toString()

Overrides:

toString in class Object

createWeight

public void createWeight(Map context,
                         IndexSearcher searcher)
                  throws IOException

Implementations should propagate createWeight to sub-ValueSources which can optionally store weight info in the context. The context object will be passed to getValues() where this info can be retrieved.

Throws:

IOException

newContext

public static Map newContext(IndexSearcher searcher)

Returns a new non-threadsafe context map.

asLongValuesSource

public LongValuesSource asLongValuesSource()

Expose this ValueSource as a LongValuesSource

asDoubleValuesSource

public DoubleValuesSource asDoubleValuesSource()

Expose this ValueSource as a DoubleValuesSource

fromDoubleValuesSource

public static ValueSource fromDoubleValuesSource(DoubleValuesSource in)

getSortField

public SortField getSortField(boolean reverse)

EXPERIMENTAL: This method is subject to change.

Get the SortField for this ValueSource. Uses the getValues(java.util.Map, org.apache.lucene.index.LeafReaderContext) to populate the SortField.

Parameters:

reverse - true if this is a reverse sort.

Returns:

The SortField for the ValueSource