Maps.EntryTransformer
Date: 2016-05-24

com.google.common.collect

## Interface Maps.EntryTransformer<K,V1,V2>

- Type Parameters:
    `K` - the key type of the input and output entries
    `V1` - the value type of the input entry
    `V2` - the value type of the output entry
  Enclosing class:
    Maps

      public static interface Maps.EntryTransformer<K,V1,V2>

  A transformation of the value of a key-value pair, using both key and value as inputs. To apply the transformation to a map, use `Maps.transformEntries(Map, EntryTransformer)`.
  Since:
    7.0

- - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `V2` | `transformEntry(K key, V1 value)` Determines an output value based on a key-value pair.

- - ### Method Detail

    - #### transformEntry

          V2 transformEntry(@Nullable
                          K key,
                          @Nullable
                          V1 value)

      Determines an output value based on a key-value pair. This method is generally expected, but not absolutely required, to have the following properties:
      - Its execution does not cause any observable side effects.
      - The computation is consistent with equals; that is, `Objects.equal``(k1, k2) &&` `Objects.equal(java.lang.Object, java.lang.Object)``(v1, v2)` implies that `Objects.equal(transformer.transform(k1, v1), transformer.transform(k2, v2))`.
      Throws:
        `java.lang.NullPointerException` - if the key or value is null and this transformer does not accept null arguments