save .workspace as json

(under .workspace.json)

falls back on old .workspace implementation

src/com/gpl/rpg/atcontentstudio/model/Preferences.java

@@ -1,19 +1,53 @@
 package com.gpl.rpg.atcontentstudio.model;
 
+import com.gpl.rpg.atcontentstudio.io.JsonSerializable;
+
 import java.awt.*;
 import java.io.Serializable;
 import java.util.HashMap;
 import java.util.Map;
 
-public class Preferences implements Serializable {
+public class Preferences implements Serializable, JsonSerializable {
 
     private static final long serialVersionUID = 2455802658424031276L;
 
     public Dimension windowSize = null;
-    public Map<String, Integer> splittersPositions = new HashMap<String, Integer>();
+    public Map<String, Integer> splittersPositions = new HashMap<>();
 
     public Preferences() {
 
     }
 
+    @Override
+    public Map toMap() {
+        Map map = new HashMap();
+
+        if(windowSize!= null){
+            Map windowSizeMap = new HashMap<>();
+            windowSizeMap.put("width", windowSize.width);
+            windowSizeMap.put("height", windowSize.height);
+            map.put("windowSize", windowSizeMap);
+        }
+
+        map.put("splittersPositions", splittersPositions);
+        return map;
+    }
+
+    @Override
+    public void fromMap(Map map) {
+        if(map == null) return;
+
+        Map windowSize1 = (Map) map.get("windowSize");
+        if(windowSize1 != null){
+            windowSize = new Dimension(((Number) windowSize1.get("width")).intValue(), ((Number) windowSize1.get("height")).intValue());
+        }
+
+        Map<String, Number> splitters = (Map<String, Number>) map.get("splittersPositions");
+        Map<String, Integer> splittersInt = new HashMap<>(splitters.size());
+        for (Map.Entry<String, Number> entry : splitters. entrySet()){
+            splittersInt.put(entry.getKey(), entry.getValue().intValue());
+        }
+        splittersPositions = splittersInt;
+
+    }
 }