org.apache.lucene.queries.function
Class ValueSource

java.lang.Object
  extended by org.apache.lucene.queries.function.ValueSource
Direct Known Subclasses:
BoolFunction, ConstNumberSource, DocFreqValueSource, DualFloatFunction, FieldCacheSource, LinearFloatFunction, LiteralValueSource, MaxDocValueSource, MultiFloatFunction, MultiFunction, MultiValueSource, NormValueSource, NumDocsValueSource, OrdFieldSource, QueryValueSource, RangeMapFloatFunction, ReciprocalFloatFunction, ReverseOrdFieldSource, ScaleFloatFunction, SingleFunction, SumTotalTermFreqValueSource, TotalTermFreqValueSource

public abstract class ValueSource
extends Object

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


Constructor Summary
ValueSource()
           
 
Method Summary
 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)
           
 SortField getSortField(boolean reverse)
          EXPERIMENTAL: This method is subject to change.
abstract  FunctionValues getValues(Map context, AtomicReaderContext 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,
                                         AtomicReaderContext readerContext)
                                  throws IOException
Gets the values for this reader and the context that was previously passed to createWeight()

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.


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, AtomicReaderContext) to populate the SortField.

Parameters:
reverse - true if this is a reverse sort.
Returns:
The SortField for the ValueSource


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