org.apache.lucene.queries.function.valuesource
Class ScaleFloatFunction

java.lang.Object
  org.apache.lucene.queries.function.ValueSource
      org.apache.lucene.queries.function.valuesource.ScaleFloatFunction

public class ScaleFloatFunction
extends ValueSource

Scales values to be between min and max.

This implementation currently traverses all of the source values to obtain their min and max.

This implementation currently cannot distinguish when documents have been deleted or documents that have no value, and 0.0 values will be used for these cases. This means that if values are normally all greater than 0.0, one can still end up with 0.0 as the min value to map from. In these cases, an appropriate map() function could be used as a workaround to change 0.0 to a value in the real range.

Field Summary

protected float	max
protected float	min
protected ValueSource	source

Constructor Summary

ScaleFloatFunction(ValueSource source, float min, float max)

Method Summary

void	createWeight(Map context, IndexSearcher searcher) Implementations should propagate createWeight to sub-ValueSources which can optionally store weight info in the context.
String	description() description of field, used in explain()
boolean	equals(Object o)
FunctionValues	getValues(Map context, AtomicReaderContext readerContext) Gets the values for this reader and the context that was previously passed to createWeight()
int	hashCode()

Methods inherited from class org.apache.lucene.queries.function.ValueSource

getSortField, newContext, toString

Methods inherited from class java.lang.Object

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

Field Detail

source

protected final ValueSource source

min

protected final float min

max

protected final float max

Constructor Detail

ScaleFloatFunction

public ScaleFloatFunction(ValueSource source,
                          float min,
                          float max)

Method Detail

description

public String description()

Description copied from class: ValueSource

description of field, used in explain()

Specified by:

description in class ValueSource

getValues

public FunctionValues getValues(Map context,
                                AtomicReaderContext readerContext)
                         throws IOException

Description copied from class: ValueSource

Gets the values for this reader and the context that was previously passed to createWeight()

Specified by:

getValues in class ValueSource

Throws:

IOException

createWeight

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

Description copied from class: ValueSource

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.

Overrides:

createWeight in class ValueSource

Throws:

IOException

hashCode

public int hashCode()

Specified by:

hashCode in class ValueSource

equals

public boolean equals(Object o)

Specified by:

equals in class ValueSource