Refactor Directions.

src/main/java/ch/fritteli/labyrinth/Tile.java

@@ -11,7 +11,7 @@ import lombok.experimental.FieldDefaults;
 public class Tile {
     // FIXME remove me; only for debugging
     @Getter
-    final Directions walls = new Directions();
+    final Walls walls = new Walls();
     @Getter
     boolean visited = false;
 
@@ -44,7 +44,7 @@ public class Tile {
     }
 
     public Option<Direction> getRandomAvailableDirection() {
-        return Stream.ofAll(this.walls.getSet(true)).shuffle().headOption();
+        return Stream.ofAll(this.walls.getUnhardenedSet()).shuffle().headOption();
     }
 
     public boolean hasWallAt(@NonNull final Direction direction) {

src/main/java/ch/fritteli/labyrinth/Walls.java

@@ -1,17 +1,14 @@
 package ch.fritteli.labyrinth;
 
 import io.vavr.collection.Stream;
-import lombok.Getter;
 import lombok.NonNull;
 
 import java.util.EnumSet;
 import java.util.HashSet;
 import java.util.Set;
 
-public class Directions {
+public class Walls {
     private final Set<Direction> directions = new HashSet<>();
-    // FIXME remove getter, only for debugging
-    @Getter
     private final Set<Direction> hardened = new HashSet<>();
 
     public boolean set(@NonNull final Direction direction) {
@@ -29,25 +26,13 @@ public class Directions {
         return this.directions.remove(direction);
     }
 
-    public void clearAll() {
-        this.directions.clear();
-        this.directions.addAll(this.hardened);
-    }
-
     public boolean isSet(@NonNull final Direction direction) {
         return this.directions.contains(direction);
     }
 
-    public Iterable<Direction> getSet() {
-        return this.getSet(false);
-    }
-
-    public Iterable<Direction> getSet(final boolean onlyBrittleWalls) {
-        if (onlyBrittleWalls) {
-            return Stream.ofAll(this.directions)
-                    .removeAll(this.hardened);
-        }
-        return Stream.ofAll(this.directions);
+    public Iterable<Direction> getUnhardenedSet() {
+        return Stream.ofAll(this.directions)
+                .removeAll(this.hardened);
     }
 
     public void harden(@NonNull final Direction direction) {