Remove all nulls (#402)

* Remove all nulls

Refactors the entire code base to remove all usages for null as a
values, and all null checks. When needed, data structures are updated to
use java.util.Optional, but in a lot of cases null are removed without
replacement.
Reimplement nextBranch and previousBranch
Minor graphical adjustment
Fix the Lizzie window not actually starting centered.
Remove the 0.98 factor on board size to remove the small region of
background above the board.
Fix an exception when creating a BufferedImage with width zero.

src/main/java/featurecat/lizzie/Config.java

@@ -72,15 +72,8 @@ private JSONObject loadAndMergeConfig(
 
     FileInputStream fp = new FileInputStream(file);
 
-    JSONObject mergedcfg = null;
-    boolean modified = false;
-    try {
-      mergedcfg = new JSONObject(new JSONTokener(fp));
-      modified = merge_defaults(mergedcfg, defaultCfg);
-    } catch (JSONException e) {
-      mergedcfg = null;
-      e.printStackTrace();
-    }
+    JSONObject mergedcfg = new JSONObject(new JSONTokener(fp));
+    boolean modified = mergeDefaults(mergedcfg, defaultCfg);
 
     fp.close();
 
@@ -105,10 +98,6 @@ private JSONObject loadAndMergeConfig(
    * @return if any correction has been made.
    */
   private boolean validateAndCorrectSettings(JSONObject config) {
-    if (config == null) {
-      return false;
-    }
-
     boolean madeCorrections = false;
 
     // Check ui configs
@@ -185,22 +174,22 @@ public Config() throws IOException {
 
   // Modifies config by adding in values from default_config that are missing.
   // Returns whether it added anything.
-  public boolean merge_defaults(JSONObject config, JSONObject defaults_config) {
+  public boolean mergeDefaults(JSONObject config, JSONObject defaultsConfig) {
     boolean modified = false;
-    Iterator<String> keys = defaults_config.keys();
+    Iterator<String> keys = defaultsConfig.keys();
     while (keys.hasNext()) {
       String key = keys.next();
-      Object new_val = defaults_config.get(key);
-      if (new_val instanceof JSONObject) {
+      Object newVal = defaultsConfig.get(key);
+      if (newVal instanceof JSONObject) {
         if (!config.has(key)) {
           config.put(key, new JSONObject());
           modified = true;
         }
-        Object old_val = config.get(key);
-        modified |= merge_defaults((JSONObject) old_val, (JSONObject) new_val);
+        Object oldVal = config.get(key);
+        modified |= mergeDefaults((JSONObject) oldVal, (JSONObject) newVal);
       } else {
         if (!config.has(key)) {
-          config.put(key, new_val);
+          config.put(key, newVal);
           modified = true;
         }
       }

src/main/java/featurecat/lizzie/Lizzie.java

@@ -10,10 +10,10 @@
 
 /** Main class. */
 public class Lizzie {
+  public static Config config;
   public static LizzieFrame frame;
-  public static Leelaz leelaz;
   public static Board board;
-  public static Config config;
+  public static Leelaz leelaz;
   public static String lizzieVersion = "0.5";
   private static String[] mainArgs;
 
@@ -24,25 +24,17 @@ public static void main(String[] args) throws IOException {
     config = new Config();
     board = new Board();
     frame = new LizzieFrame();
-    new Thread(Lizzie::run).start();
-  }
+    leelaz = new Leelaz();
 
-  public static void run() {
-    try {
-      leelaz = new Leelaz();
-      if (config.handicapInsteadOfWinrate) {
-        leelaz.estimatePassWinrate();
-      }
-      if (mainArgs.length == 1) {
-        frame.loadFile(new File(mainArgs[0]));
-      } else if (config.config.getJSONObject("ui").getBoolean("resume-previous-game")) {
-        board.resumePreviousGame();
-      }
-      leelaz.togglePonder();
-    } catch (IOException e) {
-      e.printStackTrace();
-      System.exit(-1);
+    if (config.handicapInsteadOfWinrate) {
+      leelaz.estimatePassWinrate();
     }
+    if (mainArgs.length == 1) {
+      frame.loadFile(new File(mainArgs[0]));
+    } else if (config.config.getJSONObject("ui").getBoolean("resume-previous-game")) {
+      board.resumePreviousGame();
+    }
+    leelaz.togglePonder();
   }
 
   public static void setLookAndFeel() {
@@ -60,25 +52,23 @@ public static void setLookAndFeel() {
   }
 
   public static void shutdown() {
-    if (board != null && config.config.getJSONObject("ui").getBoolean("confirm-exit")) {
+    if (config.config.getJSONObject("ui").getBoolean("confirm-exit")) {
       int ret =
           JOptionPane.showConfirmDialog(
               null, "Do you want to save this SGF?", "Save SGF?", JOptionPane.OK_CANCEL_OPTION);
       if (ret == JOptionPane.OK_OPTION) {
         LizzieFrame.saveFile();
       }
     }
-    if (board != null) {
-      board.autosaveToMemory();
-    }
+    board.autosaveToMemory();
 
     try {
       config.persist();
     } catch (IOException e) {
       e.printStackTrace(); // Failed to save config
     }
 
-    if (leelaz != null) leelaz.shutdown();
+    leelaz.shutdown();
     System.exit(0);
   }
 
@@ -88,33 +78,27 @@ public static void shutdown() {
    * @param index engine index
    */
   public static void switchEngine(int index) {
-
-    String commandLine = null;
+    String commandLine;
     if (index == 0) {
+      String networkFile = Lizzie.config.leelazConfig.getString("network-file");
       commandLine = Lizzie.config.leelazConfig.getString("engine-command");
-      commandLine =
-          commandLine.replaceAll(
-              "%network-file", Lizzie.config.leelazConfig.getString("network-file"));
+      commandLine = commandLine.replaceAll("%network-file", networkFile);
     } else {
-      JSONArray commandList = Lizzie.config.leelazConfig.getJSONArray("engine-command-list");
-      if (commandList != null && commandList.length() >= index) {
-        commandLine = commandList.getString(index - 1);
-      } else {
-        index = -1;
+      JSONArray engines = Lizzie.config.leelazConfig.getJSONArray("engine-command-list");
+      if (engines.length() < index) {
+        return;
       }
+      commandLine = engines.getString(index - 1);
     }
-    if (index < 0
-        || commandLine == null
-        || commandLine.trim().isEmpty()
-        || index == Lizzie.leelaz.currentEngineN()) {
+    if (commandLine.trim().isEmpty() || index == Lizzie.leelaz.currentEngineN()) {
       return;
     }
 
-    // Workaround for leelaz cannot exit when restarting
+    // Workaround for leelaz no exiting when restarting
     if (leelaz.isThinking) {
       if (Lizzie.frame.isPlayingAgainstLeelaz) {
         Lizzie.frame.isPlayingAgainstLeelaz = false;
-        Lizzie.leelaz.togglePonder(); // we must toggle twice for it to restart pondering
+        Lizzie.leelaz.togglePonder(); // Toggle twice for to restart pondering
         Lizzie.leelaz.isThinking = false;
       }
       Lizzie.leelaz.togglePonder();

src/main/java/featurecat/lizzie/analysis/Branch.java

@@ -3,41 +3,39 @@
 import featurecat.lizzie.rules.Board;
 import featurecat.lizzie.rules.BoardData;
 import featurecat.lizzie.rules.Stone;
-import featurecat.lizzie.rules.Zobrist;
 import java.util.List;
+import java.util.Optional;
 
 public class Branch {
   public BoardData data;
 
   public Branch(Board board, List<String> variation) {
-    int moveNumber = 0;
-    int[] lastMove = board.getLastMove();
     int[] moveNumberList = new int[Board.boardSize * Board.boardSize];
-    boolean blackToPlay = board.getData().blackToPlay;
-
-    Stone lastMoveColor = board.getData().lastMoveColor;
-    Stone[] stones = board.getStones().clone();
-    Zobrist zobrist = board.getData().zobrist == null ? null : board.getData().zobrist.clone();
+    int moveNumber = 0;
+    double winrate = 0.0;
+    int playouts = 0;
 
-    // Dont care about winrate for branch
     this.data =
         new BoardData(
-            stones,
-            lastMove,
-            lastMoveColor,
-            blackToPlay,
-            zobrist,
+            board.getStones().clone(),
+            board.getLastMove(),
+            board.getData().lastMoveColor,
+            board.getData().blackToPlay,
+            board.getData().zobrist.clone(),
             moveNumber,
             moveNumberList,
             board.getData().blackCaptures,
             board.getData().whiteCaptures,
-            0.0,
-            0);
+            winrate,
+            playouts);
 
     for (int i = 0; i < variation.size(); i++) {
-      int[] coord = Board.convertNameToCoordinates(variation.get(i));
-      if (coord == null) break;
-      data.lastMove = coord;
+      Optional<int[]> coordOpt = Board.asCoordinates(variation.get(i));
+      if (!coordOpt.isPresent()) {
+        break;
+      }
+      int[] coord = coordOpt.get();
+      data.lastMove = coordOpt;
       data.stones[Board.getIndex(coord[0], coord[1])] =
           data.blackToPlay ? Stone.BLACK_GHOST : Stone.WHITE_GHOST;
       data.moveNumberList[Board.getIndex(coord[0], coord[1])] = i + 1;