Optimized the transaction module

com/Acrobot/ChestShop/Economy/Economy.java

@@ -15,6 +15,10 @@ import static com.Acrobot.Breeze.Utils.NumberUtil.roundUp;
 public class Economy {
     private static EconomyManager manager = new EconomyManager();
 
+    public static boolean transactionCanFail() {
+        return manager.transactionCanFail();
+    }
+
     public static boolean isOwnerEconomicallyActive(Inventory inventory) {
         return !ChestShopSign.isAdminShop(inventory) || !getServerAccountName().isEmpty();
     }

com/Acrobot/ChestShop/Economy/EconomyManager.java

@@ -6,6 +6,10 @@ import com.Acrobot.ChestShop.ChestShop;
  * @author Acrobot
  */
 public class EconomyManager {
+    public boolean transactionCanFail() {
+        return false;
+    }
+
     public boolean hasAccount(String player) {
         printError();
         return false;

com/Acrobot/ChestShop/Economy/Register.java

@@ -12,6 +12,10 @@ public class Register extends EconomyManager {
         this.method = method;
     }
 
+    public boolean transactionCanFail() {
+        return false;
+    }
+
     public boolean hasAccount(String player) {
         return method.hasAccount(player);
     }

com/Acrobot/ChestShop/Economy/Vault.java

@@ -9,6 +9,10 @@ import org.bukkit.plugin.RegisteredServiceProvider;
 public class Vault extends EconomyManager {
     private static net.milkbowl.vault.economy.Economy vaultPlugin;
 
+    public boolean transactionCanFail() {
+        return getPluginName().equals("Gringotts") || getPluginName().equals("GoldIsMoney") || getPluginName().equals("MultiCurrency");
+    }
+
     public boolean hasAccount(String player) {
         return vaultPlugin.hasAccount(player);
     }

com/Acrobot/ChestShop/Listeners/PreTransaction/PartialTransactionModule.java

@@ -50,11 +50,13 @@ public class PartialTransactionModule implements Listener {
 
         String seller = event.getOwner().getName();
 
-        if (Economy.add(seller, price)) {
-            Economy.subtract(seller, price); //Cash can be safely deposited
-        } else {
-            event.setCancelled(SHOP_DEPOSIT_FAILED);
-            return;
+        if (Economy.transactionCanFail()) {
+            if (Economy.add(seller, price)) {
+                Economy.subtract(seller, price); //Cash can be safely deposited
+            } else {
+                event.setCancelled(SHOP_DEPOSIT_FAILED);
+                return;
+            }
         }
 
         stock = event.getStock();