org.apache.commons.collections4.functors

## Class MapTransformer<I,O>

- java.lang.Object
- - org.apache.commons.collections4.functors.MapTransformer<I,O>

- All Implemented Interfaces:
    Serializable, Transformer<I,O>

      public final class MapTransformer<I,O>
      extends Object
      implements Transformer<I,O>, Serializable

  Transformer implementation that returns the value held in a specified map using the input parameter as a key.
  Since:
    3.0
  Version:
    $Id: MapTransformer.java 1476582 2013-04-27 14:13:54Z tn $
  See Also:
    Serialized Form

- - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Map<? super I,? extends O>` | `getMap()` Gets the map to lookup in.
    `static <I,O> Transformer<I,O>` | `mapTransformer(Map<? super I,? extends O> map)` Factory to create the transformer.
    `O` | `transform(I input)` Transforms the input to result by looking it up in a `Map`.

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

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Method Detail

    - #### mapTransformer

          public static <I,O> Transformer<I,O> mapTransformer(Map<? super I,? extends O> map)

      Factory to create the transformer.

      If the map is null, a transformer that always returns null is returned.

      Type Parameters:
        `I` - the input type
        `O` - the output type
      Parameters:
        `map` - the map, not cloned
      Returns:
        the transformer

    - #### transform

          public O transform(I input)

      Transforms the input to result by looking it up in a `Map`.
      Specified by:
        `transform` in interface `Transformer<I,O>`
      Parameters:
        `input` - the input object to transform
      Returns:
        the transformed result

    - #### getMap

          public Map<? super I,? extends O> getMap()

      Gets the map to lookup in.
      Returns:
        the map
      Since:
        3.1

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