android/guava/src/com/google/common/collect/Maps.java
static <K, V1, V2> Function<Entry<K, V1>, Entry<K, V2>> asEntryToEntryFunction(
      final EntryTransformer<? super K, ? super V1, V2> transformer) {
    checkNotNull(transformer);
    return new Function<Entry<K, V1>, Entry<K, V2>>() {
      @Override
      public Entry<K, V2> apply(final Entry<K, V1> entry) {
        return transformEntry(transformer, entry);
      }
    };
  }
static <K, V1, V2> Function<Entry<K, V1>, Entry<K, V2>> asEntryToEntryFunction(
      final EntryTransformer<? super K, ? super V1, V2> transformer) {
    checkNotNull(transformer);
    return new Function<Entry<K, V1>, Entry<K, V2>>() {
      @Override
      public Entry<K, V2> apply(final Entry<K, V1> entry) {
        return transformEntry(transformer, entry);
      }
    };
  }
Views an entry transformer as a function from entries to entries.