Add method to find sell orders for a buy order

src/OrderMatching.java

@@ -42,21 +42,21 @@ public class OrderMatching {
 				if (qty >= 0) {				
 					// modify sell order quantity to prevent 
 					// repeated purchases
-					s.setQty(s.getQty() - b.getQty());
+					s.setQty(qty);
 					matchedOrders.add(b);
-				} else {
-					s.setQty(0);
-				
+				} else {				
 					// create a temporary BuyOrder with quantity equal to 
 					// the remaining stocks in sell order
 					BuyOrder _b = new BuyOrder(b);
 					_b.setQty(s.getQty());
 					// add it to buy orders queue
 					matchedOrders.add(_b);
-					
+
+					s.setQty(0);
+
 					// modify buy order's quantity to reflect quantity
 					// remaining after trade
-					b.setQty(b.getQty() - s.getQty());
+					b.setQty(b.getQty() - _b.getQty());
 				}
 			}	
 		}
@@ -74,4 +74,63 @@ public class OrderMatching {
 		return matchedOrders;
 	}
 	
+	/*
+	 * Finds all sell orders for current buy order
+	 */
+	ArrayList<SellOrder> findSellOrders(BuyOrder b) {
+		ArrayList<SellOrder> matchedOrders = new ArrayList<>();
+		
+		// Iterate over sell orders queue
+		for (SellOrder s : sellOrderQueue) {
+			// if current buy order has already found all sellers,
+			// exit the loop
+			if (b.getQty() <= 0) break;
+			
+			// check if trade is possible
+			if (buySellOrderMatch(b, s)) {
+				
+				int qty = b.getQty() - s.getQty();
+				
+				if (qty >= 0) {				
+					// modify buy order quantity to prevent 
+					// repeated purchases
+					b.setQty(qty);
+					matchedOrders.add(s);
+				} else {
+					// create a temporary SellOrder with quantity equal to 
+					// the remaining stocks in buy order
+					SellOrder _s = new SellOrder(s);
+					_s.setQty(b.getQty());
+
+					// add it to matched orders queue
+					matchedOrders.add(_s);
+					b.setQty(0);
+
+					// modify sell order's quantity to reflect quantity
+					// remaining after trade
+					s.setQty(s.getQty() - _s.getQty());
+				}
+			}	
+		}
+		
+		// if there is still some stocks to buy
+		// add it to buy orders queue
+		if (b.getQty() > 0) buyOrderQueue.add(b);
+		
+		// remove all sell orders that were matched from
+		// sell order queue
+		for (SellOrder s : matchedOrders) {
+			sellOrderQueue.remove(s);
+		}
+		
+		return matchedOrders;
+	}
+	
+	List<SellOrder> printSellOrderQueue() {
+		return sellOrderQueue;
+	}
+	
+	List<BuyOrder> printBuyOrderQueue() {
+		return buyOrderQueue;
+	}
 }