interface commit

src/org/university/core/Account.java

@@ -3,11 +3,13 @@ package org.university.core;
 public class Account
 {
     private AbstractEmployee owner;
-    private double credit;
+    private double credit = 0;
+    private double demand = 0;
 
     public Account(AbstractEmployee owner, double credit) {
         this.owner = owner;
         this.credit = credit;
+        this.demand = 0;
     }
 
     public AbstractEmployee getOwner() {
@@ -25,4 +27,12 @@ public class Account
     public void setCredit(double credit) {
         this.credit = credit;
     }
+
+    public double getDemand() {
+        return demand;
+    }
+
+    public void setDemand(double demand) {
+        this.demand = demand;
+    }
 }
\ No newline at end of file

src/org/university/core/AccountingManagement.java

@@ -12,10 +12,10 @@ public class AccountingManagement
         boolean flag = true;
         for (Account account:accounts)
         {
-            if (account.getOwner()==employee)
+            if (account.getOwner()== employee)
             {
                 double amount = employee.callCurrentIncome();
-                account.setCredit(account.getCredit()+amount);
+                account.setCredit(account.getCredit() + amount);
                 flag = false;
                 Statement s = new Statement(amount,employee.callEmployee());
                 statements.add(s);
@@ -31,4 +31,14 @@ public class AccountingManagement
         }
 
     }
+    public void settle(AccountingInterface employee){
+        for(Account account:accounts){
+            if(account.getOwner() == employee){
+                if(account.getDemand() > 0){
+                    account.setCredit(account.getCredit() + account.getDemand());
+                    account.setDemand(0);
+                }
+            }
+        }
+    }
 }

src/org/university/core/Professor.java

@@ -30,4 +30,8 @@ public class Professor extends AbstractEmployee
     }
 
 
+    @Override
+    public AbstractEmployee callEmployee() {
+        return null;
+    }
 }

src/org/university/core/ServiceEmployee.java

@@ -24,6 +24,10 @@ public class ServiceEmployee extends AbstractEmployee
         else
         return false;
     }
+    @Override
+    public AbstractEmployee callEmployee() {
+        return null;
+    }
 
 
 }