HCOLL-81 extend support for mapForkey to all maps.

src/main/java/net/openhft/chronicle/map/ChronicleMap.java

@@ -166,7 +166,7 @@ public interface ChronicleMap<K, V> extends ConcurrentMap<K, V>, ChronicleHash {
      * defaultValueProvider.}
      *
      * <p>If the {@code ChronicleMap} is off-heap updatable, i. e. created via {@link
-     * ChronicleMapBuilder} builder (values are {@link Byteable}), there is one more option of
+     * ChronicleMapBuilder} builder (values are {@tlink Byteable}), there is one more option of
      * what to do if the key is absent in the map, see {@link ChronicleMapBuilder#prepareValueBytesOnAcquire(PrepareValueBytes)}.
      * By default, value bytes are just zeroed out, no default value, either provided for key or constant, is
      * put for the absent key.
@@ -182,5 +182,16 @@ public interface ChronicleMap<K, V> extends ConcurrentMap<K, V>, ChronicleHash {
     @NotNull
     WriteContext<K, V> acquireUsingLocked(@NotNull K key, @NotNull V usingValue);
 
+    /**
+     * Apply a mapping to the value returned by a key and return a result.
+     * A read lock is assumed.
+     *
+     * @param key      to apply the mapping to
+     * @param function to calculate a result
+     * @param <R>      return type.
+     * @return the result of the function.
+     */
+    <R> R mapForKey(K key, @NotNull Function<? super V, R> function);
+
 }