Major code clean-up, some changes related to sonar, other to style.

src/main/java/carcassonne/control/state/AbstractGameState.java

@@ -10,6 +10,7 @@
 import carcassonne.model.tile.TileStack;
 import carcassonne.settings.GameSettings;
 import carcassonne.view.ViewFacade;
+import carcassonne.view.main.MainView;
 
 /**
  * Is the abstract state of the state machine.
@@ -113,7 +114,7 @@ protected void startNewRound(int playerCount) {
         updateStackSize();
         if (settings.isGridSizeChanged()) {
             settings.setGridSizeChanged(false);
-            views.onMainView(it -> it.rebuildGrid());
+            views.onMainView(MainView::rebuildGrid);
         }
         GridSpot spot = grid.getFoundation(); // starting spot.
         views.onMainView(it -> it.setTile(spot.getTile(), spot.getX(), spot.getY()));

src/main/java/carcassonne/control/state/StateGameOver.java

@@ -5,6 +5,8 @@
 import carcassonne.model.grid.GridPattern;
 import carcassonne.settings.GameSettings;
 import carcassonne.view.ViewFacade;
+import carcassonne.view.main.MainView;
+import carcassonne.view.menubar.Scoreboard;
 import carcassonne.view.util.GameMessage;
 
 /**
@@ -65,7 +67,7 @@ public void placeTile(int x, int y) {
      */
     @Override
     public void skip() {
-        views.onScoreboard(it -> it.disable());
+        views.onScoreboard(Scoreboard::disable);
         exit();
         changeState(StateIdle.class);
     }
@@ -82,7 +84,7 @@ protected void entry() {
         }
         updateScores();
         updateStackSize();
-        views.onMainView(it -> it.resetMenuState());
+        views.onMainView(MainView::resetMenuState);
         GameMessage.showMessage(GAME_OVER_MESSAGE + round.winningPlayers());
         views.showGameStatistics(round);
     }

src/main/java/carcassonne/control/state/StateManning.java

@@ -10,6 +10,7 @@
 import carcassonne.model.tile.Tile;
 import carcassonne.settings.GameSettings;
 import carcassonne.view.ViewFacade;
+import carcassonne.view.main.MainView;
 import carcassonne.view.util.GameMessage;
 
 /**
@@ -120,7 +121,7 @@ private void startNextTurn() {
             changeState(StateGameOver.class);
         } else {
             if (!round.getActivePlayer().isComputerControlled()) {
-                views.onMainView(it -> it.resetPlacementHighlights());
+                views.onMainView(MainView::resetPlacementHighlights);
             }
             round.nextTurn();
             views.onMainView(it -> it.setCurrentPlayer(round.getActivePlayer()));

src/main/java/carcassonne/control/state/StatePlacing.java

@@ -11,6 +11,7 @@
 import carcassonne.model.tile.Tile;
 import carcassonne.settings.GameSettings;
 import carcassonne.view.ViewFacade;
+import carcassonne.view.main.MainView;
 import carcassonne.view.util.GameMessage;
 
 /**
@@ -86,7 +87,7 @@ private void skipPlacingTile() {
             }
         });
         if (!round.getActivePlayer().isComputerControlled()) {
-            views.onMainView(it -> it.resetPlacementHighlights());
+            views.onMainView(MainView::resetPlacementHighlights);
         }
         round.nextTurn();
         views.onMainView(it -> it.setCurrentPlayer(round.getActivePlayer()));

src/main/java/carcassonne/model/ai/RuleBasedComparator.java

@@ -29,7 +29,8 @@ public int compare(AbstractCarcassonneMove firstMove, AbstractCarcassonneMove se
         if (firstMove.getGainedMeeples() != secondMove.getGainedMeeples()) {
             // Rule 1: Prefer move with a maximal meeple gain
             return firstMove.getGainedMeeples() - secondMove.getGainedMeeples();
-        } else if (firstMove.involvesMeeplePlacement() != secondMove.involvesMeeplePlacement()) {
+        }
+        if (firstMove.involvesMeeplePlacement() != secondMove.involvesMeeplePlacement()) {
             // Rule 2: Prefer move without meeple placement
             return preferFalse(firstMove.involvesMeeplePlacement(), secondMove.involvesMeeplePlacement());
         }

src/main/java/carcassonne/model/grid/FieldsPattern.java

@@ -37,7 +37,7 @@ public FieldsPattern(GridSpot startingSpot, GridDirection startingDirection) {
         startingSpot.setTag(startingDirection, this); // initial tag, is needed for adding meeples!
         add(startingSpot); // initial tile
         buildPattern(startingSpot, startingDirection);
-        adjacentCastles.forEach(it -> it.removeOwnTags()); // also remove the tile tags of the marked adjacentCastles
+        adjacentCastles.forEach(CastleAndRoadPattern::removeOwnTags); // also remove the tile tags of the marked adjacentCastles
     }
 
     @Override
@@ -128,12 +128,12 @@ private List<GridDirection> getFieldConnections(GridDirection position, Tile til
     private GridDirection getFieldOpposite(GridDirection position, GridDirection neighborDirection) {
         if (position.isSmallerOrEquals(WEST)) {
             return position.opposite(); // top, right, bottom, left are simply inverted
-        } else if (position.isSmallerOrEquals(NORTH_WEST)) {
+        }
+        if (position.isSmallerOrEquals(NORTH_WEST)) {
             if (neighborDirection.isLeftOf(position)) { // neighbor to the left of the corner
                 return position.opposite().nextDirectionTo(LEFT).nextDirectionTo(LEFT); // return opposite and two to the right
-            } else { // neighbor to the right of the corner
-                return position.opposite().nextDirectionTo(RIGHT).nextDirectionTo(RIGHT); // return opposite and two to the left
             }
+            return position.opposite().nextDirectionTo(RIGHT).nextDirectionTo(RIGHT); // return opposite and two to the left
         }
         return position; // middle stays middle
     }

src/main/java/carcassonne/model/grid/Grid.java

@@ -59,7 +59,7 @@ public List<GridPattern> getAllPatterns() {
                 }
             }
         }
-        patterns.forEach(it -> it.removeTileTags());  // IMPORTANT
+        patterns.forEach(GridPattern::removeTileTags);  // IMPORTANT
         return patterns;
     }
 
@@ -93,7 +93,7 @@ public Collection<GridPattern> getLocalPatterns(GridSpot spot) {
         for (GridSpot neighbor : getNeighbors(spot, false, GridDirection.directNeighbors())) {
             gridPatterns.addAll(neighbor.createPatternList());
         }
-        gridPatterns.forEach(it -> it.removeTileTags()); // VERY IMPORTANT!
+        gridPatterns.forEach(GridPattern::removeTileTags); // VERY IMPORTANT!
         return gridPatterns; // get patterns.
     }
 
@@ -108,7 +108,7 @@ public Collection<GridPattern> getModifiedPatterns(GridSpot spot) {
             throw new IllegalArgumentException("Can't check for patterns on an free grid space");
         }
         Collection<GridPattern> modifiedPatterns = spot.createPatternList();
-        modifiedPatterns.forEach(it -> it.removeTileTags()); // VERY IMPORTANT!
+        modifiedPatterns.forEach(GridPattern::removeTileTags); // VERY IMPORTANT!
         return modifiedPatterns; // get patterns.
     }
 
@@ -122,9 +122,8 @@ public GridSpot getNeighbor(GridSpot spot, GridDirection direction) {
         List<GridSpot> neighbors = getNeighbors(spot, false, direction);
         if (neighbors.isEmpty()) {
             return null; // return null if tile not placed or not on grid.
-        } else {
-            return neighbors.get(0);
         }
+        return neighbors.get(0);
     }
 
     /**
@@ -241,7 +240,8 @@ public boolean place(int x, int y, Tile tile) {
     private void checkParameters(GridSpot spot) {
         if (spot == null) {
             throw new IllegalArgumentException("Spot can't be null!");
-        } else if (!spots[spot.getX()][spot.getY()].equals(spot)) {
+        }
+        if (!spots[spot.getX()][spot.getY()].equals(spot)) {
             throw new IllegalArgumentException("Spot is not on the grid!");
         }
     }
@@ -265,7 +265,8 @@ private void checkParameters(int x, int y) {
     private void checkParameters(Tile tile) {
         if (tile == null) {
             throw new IllegalArgumentException("Tile can't be null.");
-        } else if (tile.getType() == TileType.Null) {
+        }
+        if (tile.getType() == TileType.Null) {
             throw new IllegalArgumentException("Tile from type TileType.Null can't be placed.");
         }
     }
@@ -274,19 +275,17 @@ private void checkParameters(Tile tile) {
     private boolean findBoundary(GridSpot spot, GridDirection direction, boolean[][] visitedPositions) {
         int newX = direction.getX() + spot.getX(); // get coordinates
         int newY = direction.getY() + spot.getY(); // of free space
-        if (isOnGrid(newX, newY)) { // if on grid
-            if (spots[newX][newY].isOccupied()) {
-                return false; // is a tile, can't go through tiles
-            } else if (!visitedPositions[newX][newY]) { // if not visited
-                visitedPositions[newX][newY] = true; // mark as visited
-                for (GridDirection newDirection : GridDirection.directNeighbors()) { // recursion
-                    if (findBoundary(spots[newX][newY], newDirection, visitedPositions)) {
-                        return true; // found boundary
-                    }
+        if (!isOnGrid(newX, newY)) { // if not on grid
+            return true; // found boundary
+        }
+        if (spots[newX][newY].isOccupied()) {
+        } else if (!visitedPositions[newX][newY]) { // if not visited
+            visitedPositions[newX][newY] = true; // mark as visited
+            for (GridDirection newDirection : GridDirection.directNeighbors()) { // recursion
+                if (findBoundary(spots[newX][newY], newDirection, visitedPositions)) {
+                    return true; // found boundary
                 }
             }
-        } else { // if not on grid
-            return true; // found boundary
         }
         return false; // has not found boundary
     }

src/main/java/carcassonne/model/grid/GridDirection.java

@@ -28,7 +28,8 @@ public enum GridDirection {
     public int getX() {
         if (this == NORTH_EAST || this == EAST || this == SOUTH_EAST) {
             return 1;
-        } else if (this == NORTH_WEST || this == WEST || this == SOUTH_WEST) {
+        }
+        if (this == NORTH_WEST || this == WEST || this == SOUTH_WEST) {
             return -1;
         }
         return 0;
@@ -41,7 +42,8 @@ public int getX() {
     public int getY() {
         if (this == SOUTH_WEST || this == SOUTH || this == SOUTH_EAST) {
             return 1;
-        } else if (this == NORTH_WEST || this == NORTH || this == NORTH_EAST) {
+        }
+        if (this == NORTH_WEST || this == NORTH || this == NORTH_EAST) {
             return -1;
         }
         return 0;
@@ -100,7 +102,8 @@ public GridDirection nextDirectionTo(RotationDirection side) {
     public GridDirection opposite() {
         if (ordinal() <= 3) { // for NORTH, EAST, SOUTH and WEST:
             return values()[smallOpposite(ordinal())];
-        } else if (ordinal() <= 7) { // for NORTH_EAST, SOUTH_EAST, SOUTH_WEST and NORTH_WEST:
+        }
+        if (ordinal() <= 7) { // for NORTH_EAST, SOUTH_EAST, SOUTH_WEST and NORTH_WEST:
             return values()[bigOpposite(ordinal())];
         }
         return CENTER; // middle is the opposite of itself.

src/main/java/carcassonne/model/grid/GridPattern.java

@@ -151,7 +151,7 @@ public void removeOwnTags() {
      * Removes all tags of all tiles of the pattern. Needs to be called after ALL patterns of a tile have been created.
      */
     public void removeTileTags() {
-        containedSpots.forEach(it -> it.removeTags());
+        containedSpots.forEach(GridSpot::removeTags);
     }
 
     @Override

src/main/java/carcassonne/model/grid/GridSpot.java

@@ -190,7 +190,7 @@ public boolean isPlaceable(Tile tile, boolean allowEnclaves) {
      * Removes all the tags from the tile.
      */
     public void removeTags() {
-        tagMap.values().forEach(it -> it.clear());
+        tagMap.values().forEach(Set::clear);
     }
 
     /**

src/main/java/carcassonne/model/terrain/TileTerrain.java

@@ -72,11 +72,10 @@ public Set<GridDirection> getMeepleSpots() {
      * @return true if connected, false if not.
      */
     public final boolean isConnected(GridDirection from, GridDirection towards) {
-        if (isDirectConnected(from, towards)) {
-            return true; // directly connected through the middle of the tile
-        } else if (from != CENTER && towards != CENTER && isIndirectConnected(from, towards)) {
+        if (isDirectConnected(from, towards) || (from != CENTER && towards != CENTER && isIndirectConnected(from, towards))) {
             return true; // is not from or to middle but indirectly connected (counter)clockwise
-        } else if (terrain.get(from) == TerrainType.FIELDS && terrain.get(towards) == TerrainType.FIELDS) {
+        }
+        if (terrain.get(from) == TerrainType.FIELDS && terrain.get(towards) == TerrainType.FIELDS) {
             return isImplicitlyConnected(from, towards); // is connected through implicit terrain information
         }
         return false;

src/main/java/carcassonne/model/tile/Tile.java

@@ -237,13 +237,12 @@ public void placeMeeple(Player player, GridDirection position, GameSettings sett
     }
 
     public void placeMeeple(Player player, GridDirection position, Meeple meeple, GameSettings settings) {
-        if (this.meeple == null && allowsPlacingMeeple(position, player, settings)) {
-            this.meeple = meeple;
-            meeple.setLocation(gridSpot);
-            meeple.setPosition(position);
-        } else {
+        if ((this.meeple != null) || !allowsPlacingMeeple(position, player, settings)) {
             throw new IllegalArgumentException("Tile can not have already a meeple placed on it: " + toString());
         }
+        this.meeple = meeple;
+        meeple.setLocation(gridSpot);
+        meeple.setPosition(position);
     }
 
     /**

src/main/java/carcassonne/model/tile/TileStack.java

@@ -56,7 +56,8 @@ public TileStack(TileDistribution distribution, int multiplier, Long sortingSeed
     public Tile drawTile() {
         if (tiles.isEmpty() && returnedTiles.isEmpty()) {
             return null; // no tile to draw!
-        } else if (tiles.isEmpty()) {
+        }
+        if (tiles.isEmpty()) {
             return returnedTiles.poll();
         }
         return tiles.pop();

src/main/java/carcassonne/model/tile/TileUtil.java

@@ -23,7 +23,7 @@ private TileUtil() {
      * @return the number of possible rotations (between 1 and 3).
      */
     public static int rotationLimitFor(TileType type) {
-        return rotations.computeIfAbsent(type, key -> determineRotationLimit(key));
+        return rotations.computeIfAbsent(type, TileUtil::determineRotationLimit);
     }
 
     /**

src/main/java/carcassonne/util/ConcurrentTileImageScaler.java

@@ -108,13 +108,13 @@ private static Image getOriginalImageUnsafe(Tile tile) {
         String imagePath = GameSettings.TILE_FOLDER_PATH + tile.getType().name() + tile.getImageIndex() + GameSettings.TILE_FILE_TYPE;
         if (TileImageScalingCache.containsScaledImage(tile, TILE_RESOLUTION, false)) {
             return TileImageScalingCache.getScaledImage(tile, TILE_RESOLUTION);
-        } else if (tile.hasEmblem()) {
+        }
+        if (tile.hasEmblem()) {
             return loadImageAndPaintEmblem(tile, imagePath);
-        } else {
-            Image image = ImageLoadingUtil.createBufferedImage(imagePath);
-            TileImageScalingCache.putScaledImage(image, tile, TILE_RESOLUTION, false);
-            return image;
         }
+        Image image = ImageLoadingUtil.createBufferedImage(imagePath);
+        TileImageScalingCache.putScaledImage(image, tile, TILE_RESOLUTION, false);
+        return image;
     }
 
     /**

src/main/java/carcassonne/view/main/MeepleLayer.java

@@ -117,14 +117,14 @@ public void placeMeeple(int x, int y, TerrainType terrain, GridDirection positio
      * Refreshes all meeple labels in this layer. This updates the images to color changes.
      */
     public void refreshLayer() {
-        meeplePanels.stream().forEach(it -> it.refreshAll());
+        meeplePanels.stream().forEach(MeepleDepictionPanel::refreshAll);
     }
 
     /**
      * Resets all meeples in the layer.
      */
     public void resetLayer() {
-        meeplePanels.stream().forEach(it -> it.resetAll());
+        meeplePanels.stream().forEach(MeepleDepictionPanel::resetAll);
     }
 
     /**

src/main/java/carcassonne/view/main/TileLayer.java

@@ -104,18 +104,18 @@ public void refreshHighlight(ImageIcon newHighlight) {
      * @param newHighlight is the new image.
      */
     public void refreshPlacementHighlights() {
-        placementHighlights.forEach(it -> it.refresh());
+        placementHighlights.forEach(TileDepiction::refresh);
     }
 
     public void resetPlacementHighlights() {
-        placementHighlights.forEach(it -> it.resetPlacementHighlight());
+        placementHighlights.forEach(TileDepiction::resetPlacementHighlight);
         placementHighlights.clear();
     }
 
     /**
      * Resets every tile label in this layer.
      */
     public void resetLayer() {
-        tileLabels.stream().forEach(it -> it.reset());
+        tileLabels.stream().forEach(TileDepiction::reset);
     }
 }

src/main/java/carcassonne/view/secondary/MeepleView.java

@@ -52,7 +52,7 @@ public void setTile(Tile tile, Player currentPlayer) {
         }
         this.tile = tile;
         setCurrentPlayer(currentPlayer);
-        ThreadingUtil.runAndCallback(() -> updatePlacementButtons(), () -> showUI());
+        ThreadingUtil.runAndCallback(this::updatePlacementButtons, this::showUI);
     }
 
     // build button grid

src/main/java/carcassonne/view/secondary/PlacementButton.java

@@ -38,12 +38,11 @@ public boolean isHackyEnabled() {
         String osName = System.getProperty(OS_NAME);
         if (osName.startsWith(MAC) || osName.equals(WINDOWS_10)) {
             return isEnabled(); // normal function on mac os x
-        } else {
-            // own implementation to fix the functionality which is destroyed by the hack. If the
-            // original isEnabled method is overwritten, it breaks some functionality (e.g.updating
-            // the background):
-            return enabled;
         }
+        // own implementation to fix the functionality which is destroyed by the hack. If the
+        // original isEnabled method is overwritten, it breaks some functionality (e.g.updating
+        // the background):
+        return enabled;
     }
 
     @Override

src/main/java/carcassonne/view/secondary/TileView.java

@@ -115,7 +115,7 @@ public void setTiles(Player currentPlayer) {
         if (!currentPlayer.getHandOfTiles().isEmpty()) {
             tiles.addAll(currentPlayer.getHandOfTiles());
             setCurrentPlayer(currentPlayer);
-            ThreadingUtil.runAndCallback(() -> updatePreviewLabels(), () -> showUI());
+            ThreadingUtil.runAndCallback(this::updatePreviewLabels, this::showUI);
         }
     }