impliment logic in exchange class

src/main/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Exchange.java

@@ -1,8 +1,11 @@
 package edu.ntnu.idi.idatt2003.gruppe42.Model;
 
+import edu.ntnu.idi.idatt2003.gruppe42.Model.Transaction.Purchase;
+import edu.ntnu.idi.idatt2003.gruppe42.Model.Transaction.Sale;
 import edu.ntnu.idi.idatt2003.gruppe42.Model.Transaction.Transaction;
 
 import java.math.BigDecimal;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -13,12 +16,14 @@ public class Exchange {
   private int week;
   private Map<String, Stock> stockMap;
   private Random random;
+  private List<Stock> stocks;
 
   public Exchange(String name, List<Stock> stocks) {
     this.name = name;
     this.week = 0;
     this.stockMap = new HashMap<String, Stock>();
     this.random = new Random();
+    this.stocks = stocks;
   }
 
   public String getName() {
@@ -30,23 +35,41 @@ public int getWeek() {
   }
 
   public boolean hasStock(String symbol) {
-    return true;
+    return stockMap.containsKey(symbol);
   }
 
   public Stock getStock(String symbol) {
-    return null;
+    return stockMap.get(symbol);
   }
 
   public List<Stock> findStocks(String searchTerm) {
-    return null;
+    List<Stock> foundStocks = new ArrayList<>();
+
+    for (Stock stock : stocks) {
+      if (stock.getCompany().equals(searchTerm)) {
+        foundStocks.add(stock);
+      }
+    }
+    return foundStocks;
   }
 
   public Transaction buy(String symbol, BigDecimal quantity, Player player) {
-    return null;
+
+    player.withdrawMoney(quantity);
+    Stock stock = getStock(symbol);
+    BigDecimal purchasePrice =  stock.getSalesPrice();
+
+    Share share = new Share(stock, quantity, purchasePrice);
+    return new Purchase(share, week);
   }
 
   public Transaction sell(Share share, Player player) {
-    return null;
+    BigDecimal salesPrice = share.getStock().getSalesPrice();
+    BigDecimal quantity = share.getQuantity();
+
+    player.addMoney(salesPrice.multiply(quantity));
+
+    return new Sale(share, week);
   }
 
   public void advance() {

src/main/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Share.java

@@ -7,7 +7,7 @@ public class Share {
   private BigDecimal quantity;
   private BigDecimal purchasePrice;
 
-  public void Share(Stock stock, BigDecimal quantity, BigDecimal purchasePrice) {
+  public Share(Stock stock, BigDecimal quantity, BigDecimal purchasePrice) {
     this.stock = stock;
     this.quantity = quantity;
     this.purchasePrice = purchasePrice;