Package 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

Fields
Modifier and Type
Field
Description
`protected final float`
`max`
`protected final float`
`min`
`protected final ValueSource`
`source`

## Constructor Summary

Constructors
Constructor
Description
`ScaleFloatFunction(ValueSource source, float min, float max)`

## Method Summary

Modifier and Type
Method
Description
`void`
`createWeight(Map<Object,Object> 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<Object,Object> context, LeafReaderContext 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

`asDoubleValuesSource, asLongValuesSource, fromDoubleValuesSource, getSortField, newContext, toString`

### Methods inherited from class java.lang.Object

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

## Field Details

### source

protected final ValueSource source

### min

protected final float min

### max

protected final float max

## Constructor Details

### ScaleFloatFunction

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

## Method Details

### 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<Object,Object> context, LeafReaderContext readerContext) throws IOException
Description copied from class: `ValueSource`
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.

Specified by:
  `getValues` in class `ValueSource`
Throws:
  `IOException`

### createWeight

public void createWeight(Map<Object,Object> 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`