HCOLL-81 extend support for mapForkey to all maps.

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

@@ -34,8 +34,6 @@ import net.openhft.lang.model.constraints.Nullable;
 import net.openhft.lang.threadlocal.Provider;
 import net.openhft.lang.threadlocal.ThreadLocalCopies;
 import org.jetbrains.annotations.NotNull;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.File;
 import java.io.IOException;
@@ -56,9 +54,6 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
         V, VW, MVW extends MetaBytesWriter<V, VW>> extends AbstractMap<K, V>
         implements ChronicleMap<K, V>, Serializable {
 
-
-    private static final Logger LOG = LoggerFactory.getLogger(VanillaChronicleMap.class);
-
     /**
      * Because DirectBitSet implementations couldn't find more than 64 continuous clear or set bits.
      */
@@ -372,6 +367,14 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
         }
     }
 
+    @Override
+    public <R> R mapForKey(K key, @NotNull Function<? super V, R> function) {
+        try (Context<K, V> entry = lookupUsing(key, null,
+                LockType.READ_LOCK, false)) {
+            return function.apply(entry.value());
+        }
+    }
+
     @NotNull
     @Override
     public WriteContext<K, V> acquireUsingLocked(@NotNull K key, @NotNull V usingValue) {