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 and Description
    --- | ---
    `protected float` | `max`
    `protected float` | `min`
    `protected ValueSource` | `source`

  - ### Constructor Summary

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

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `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, 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 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,
                                          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 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`

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