Kotlin'D Counter class, apparently it's been Java this whole time and I didn't even notice

core/src/com/unciv/logic/automation/NextTurnAutomation.kt

@@ -32,7 +32,7 @@ class NextTurnAutomation{
     }
 
     private fun buyBuildingOrUnit(civInfo: CivilizationInfo) {
-        //allow AI spending money to purchase building & unit. Buying staff has slightly lower priority than buying tech.
+        //allow AI spending money to purchase building & unit
         for (city in civInfo.cities.sortedByDescending{ it.population.population }) {
             val construction = city.cityConstructions.getCurrentConstruction()
             if (construction.canBePurchased()

core/src/com/unciv/logic/city/CityInfo.kt

@@ -128,7 +128,7 @@ class CityInfo {
         }
 
         for (building in cityConstructions.getBuiltBuildings().filter { it.requiredResource != null }) {
-            val resource = GameBasics.TileResources[building.requiredResource]
+            val resource = GameBasics.TileResources[building.requiredResource]!!
             cityResources.add(resource, -1)
         }
 

core/src/com/unciv/logic/civilization/CivilizationInfo.kt

@@ -230,7 +230,7 @@ class CivilizationInfo {
         val civResources = Counter<TileResource>()
         for (city in cities) civResources.add(city.getCityResources())
         for (dip in diplomacy.values) civResources.add(dip.resourcesFromTrade())
-        for(resource in getCivUnits().mapNotNull { it.baseUnit.requiredResource }.map { GameBasics.TileResources[it] })
+        for(resource in getCivUnits().mapNotNull { it.baseUnit.requiredResource }.map { GameBasics.TileResources[it]!! })
             civResources.add(resource,-1)
         return civResources
     }

core/src/com/unciv/models/Counter.java

@@ -1,36 +0,0 @@
-package com.unciv.models;
-
-import java.util.LinkedHashMap;
-
-public class Counter<K> extends LinkedHashMap<K,Integer> {
-
-    public Integer get(Object key){ // don't return null if empty
-        if(containsKey(key)) return super.get(key);
-        else return 0;
-    }
-
-    public void add(K key, int value){
-        if(!containsKey(key)) put(key,value);
-        else put(key,get(key)+value);
-        if(get(key)==0) remove(key); // No objects of this sort left, no need to count
-    }
-
-    public void add(Counter<K> other){
-        for (K key : other.keySet()) {
-            add(key,other.get(key));
-        }
-    }
-
-    public void remove(Counter<K> other){
-        for (K key : other.keySet()) {
-            add(key,-other.get(key));
-        }
-    }
-
-    @Override
-    public Counter<K> clone() {
-        Counter<K> newCounter = new Counter<K>();
-        newCounter.add(this);
-        return newCounter;
-    }
-}

core/src/com/unciv/models/Counter.kt

@@ -0,0 +1,38 @@
+package com.unciv.models
+
+import java.util.*
+
+class Counter<K> : LinkedHashMap<K, Int>() {
+
+    override operator fun get(key: K): Int? { // don't return null if empty
+        if (containsKey(key))
+            return super.get(key)
+        else return 0
+    }
+
+    fun add(key: K, value: Int) {
+        if (!containsKey(key))
+            put(key, value)
+        else
+            put(key, get(key)!! + value)
+        if (get(key) == 0) remove(key) // No objects of this sort left, no need to count
+    }
+
+    fun add(other: Counter<K>) {
+        for (key in other.keys) {
+            add(key, other[key]!!)
+        }
+    }
+
+    fun remove(other: Counter<K>) {
+        for (key in other.keys) {
+            add(key, -other[key]!!)
+        }
+    }
+
+    override fun clone(): Counter<K> {
+        val newCounter = Counter<K>()
+        newCounter.add(this)
+        return newCounter
+    }
+}