src/main/java/de/towerdefence/server/match/Match.java

@@ -4,7 +4,6 @@ import de.towerdefence.server.player.Player;
 import de.towerdefence.server.server.channels.match.money.PlayerMoneyCallback;
 import de.towerdefence.server.server.channels.match.placing.InvalidPlacementReason;
 import de.towerdefence.server.server.channels.match.placing.Tower;
-import lombok.AllArgsConstructor;
 import lombok.Getter;
 
 import java.util.Optional;
@@ -12,6 +11,7 @@ import java.util.Optional;
 @Getter
 public class Match {
 
+    public static final int TOWER_PRICE = 20;
     public final static int MAP_SIZE_X = 10;
     public final static int MAP_SIZE_Y = 20;
     public final static int START_MONEY = 50;
@@ -59,11 +59,13 @@ public class Match {
             if (player1Map[x][y] != null) {
                 throw new InvalidPlacementException(InvalidPlacementReason.LOCATION_USED);
             }
+            removeMoney(player, TOWER_PRICE);
             player1Map[x][y] = tower;
         } else {
             if (player2Map[x][y] != null) {
                 throw new InvalidPlacementException(InvalidPlacementReason.LOCATION_USED);
             }
+            removeMoney(player, TOWER_PRICE);
             player2Map[x][y] = tower;
         }
         return getOpponent(player);
@@ -87,16 +89,24 @@ public class Match {
         player2Money += money;
     }
 
-    public void removeMoney(Player player, int money) {
+    public void removeMoney(Player player, int price) throws InvalidPlacementException {
         if (player == player1) {
-            player1Money -= money;
+            if (price < player1Money) {
+                player1Money -= price;
+            } else {
+                throw new InvalidPlacementException(InvalidPlacementReason.NOT_ENOUGH_MONEY);
+            }
         }
         if (player == player2) {
-            player2Money -= money;
+            if (price < player2Money) {
+                player2Money -= price;
+            } else {
+                throw new InvalidPlacementException(InvalidPlacementReason.NOT_ENOUGH_MONEY);
+            }
         }
     }
 
-    public void setPlayerMoneyCallback( Player player, PlayerMoneyCallback playerMoneyCallback) {
+    public void setPlayerMoneyCallback(Player player, PlayerMoneyCallback playerMoneyCallback) {
         if (player == player1) {
             this.player1MoneyCallback = playerMoneyCallback;
         }

src/main/java/de/towerdefence/server/match/MatchService.java

@@ -29,7 +29,7 @@ public class MatchService {
     /**
      * @return opponent
      */
-    public Player placeTower(Player player, int x, int y) throws InvalidPlacementException {
+    public Player placeTower(Player player, int x, int y) throws InvalidPlacementException{
         return playerMatches.get(player).addTower(player, new Tower(), x, y);
     }
 

src/main/java/de/towerdefence/server/server/channels/match/placing/InvalidPlacementReason.java

@@ -7,7 +7,8 @@ import lombok.Getter;
 @AllArgsConstructor
 public enum InvalidPlacementReason {
     OUT_OF_BOUNDS("out-of-bounds"),
-    LOCATION_USED("location-used");
+    LOCATION_USED("location-used"),
+    NOT_ENOUGH_MONEY("not-enough-money");
 
     private final String jsonName;
 }

ws/ws.yml

@@ -218,6 +218,7 @@ channels:
               enum:
                 - "out-of-bounds"
                 - "location-used"
+                - "not-enough-money"
           required:
             - $id
             - x