Order creation verifies available assets

src/opensesim/world/TradingEngine.java

@@ -45,6 +45,7 @@ class TradingEngine implements TradingAPI {
 
     /**
      * Construct a trading engine for an asset pair
+     *
      * @param pair The AssetPair obect to create the tradinge engine for
      * @param outer Outer class - points to an Exchange object thins trading
      * engine belongs to.
@@ -87,7 +88,6 @@ class TradingEngine implements TradingAPI {
         SortedSet<Order> ul_buy = order_books.get(Order.Type.BUY);
         SortedSet<Order> ul_sell = order_books.get(Order.Type.SELL);
 
-        
         double volume_total = 0;
         double money_total = 0;
         while (true) {
@@ -233,18 +233,90 @@ class TradingEngine implements TradingAPI {
 
     @Override
     public Order createOrder(Account account, Order.Type type, double volume, double limit) {
-        Order o = new opensesim.world.Order(this, account, type, volume, limit);
+        synchronized (account) {
+
+            // Round volume 
+            double v = assetpair.getAsset().roundToDecimals(volume);
+
+            // Order volume must be grater than 0.0.
+            if (v <= 0.0) {
+                return null;
+            }
+
+            // Round currency (limit)
+            double l = assetpair.getCurrency().roundToDecimals(limit);
+
+            double order_limit;
+
+            switch (type) {
+                case BUYLIMIT: {
+                    // verfify available currency for a buy limit order
+                    AbstractAsset currency = this.assetpair.getCurrency();
+                    Double avail = account.getAvail(currency);
+
+                    // return if not enough money is available
+                    if (avail < v * l) {
+                        return null;
+                    }
+
+                    // reduce the available money 
+                    account.assets_avail.put(currency, avail - v * l);
+                    order_limit = l;
+                    break;
+                }
+
+                case BUY: {
+                    // For an unlimited by order there is nothing to check
+                    // other than currency is > 0.0
+                    AbstractAsset currency = this.assetpair.getCurrency();
+                    Double avail = account.getAvail(currency);
+                     if(avail <=0.0){
+                         return null;
+                     }
+
+                    // All available monney is assigned to this unlimited order
+                    account.assets_avail.put(currency, 0.0);
+                    // we "mis"use order_limit to memorize occupied ammount \
+                    // of currency
+                    order_limit = avail;
+
+                    break;
+                }
+
+                case SELLLIMIT:
+                case SELL: {
+
+                    // verfiy sell limit
+                    AbstractAsset asset = this.assetpair.getAsset();
+                    Double avail = account.getAvail(asset);
+
+                    if (avail < v) {
+                        // not enough items of asset (shares) available
+                        return null;
+                    }
+                    account.assets_avail.put(asset, avail - v);
+                    order_limit = l;
+                    break;
+                }
+
+                default:
+                    return null;
+
+            }
+
+            Order o = new opensesim.world.Order(this, account, type, v, order_limit);
+
             System.out.printf("The new Order has: volume: %f limit: %f\n", o.getVolume(), o.getLimit());
             synchronized (this) {
                 order_books.get(o.type).add(o);
             }
+
             for (FiringEvent e : book_listener) {
                 e.fire();
             }
             return o;
         }
-    
+    }
-    
 
     HashSet<FiringEvent> book_listener = new HashSet<>();
 
@@ -263,7 +335,6 @@ class TradingEngine implements TradingAPI {
             case SELL:
                 return Collections.unmodifiableSet(askbook);
 
-                
         }
         return null;
 //        return Collections.unmodifiableSet(order_books.get(type));
@@ -279,7 +350,4 @@ class TradingEngine implements TradingAPI {
         return getOrderBook(Order.Type.SELL);
     }
 
- 
-    
-  
 }