add Head of a cathedra

src/cathedra/Cathedra.java

@@ -1,6 +1,7 @@
 package cathedra;
 
 
+import account.Account;
 import faculty.Faculty;
 
 
@@ -13,4 +14,8 @@ public interface Cathedra {
     void setName(String name);
 
     void setFaculty(Faculty faculty);
+
+    Account getHead();
+
+    void setHead(Account head);
 }

src/cathedra/CathedraImpl.java

@@ -1,6 +1,9 @@
 package cathedra;
 
 
+import account.Account;
+import account.Permission;
+import account.RoleManager;
 import faculty.Faculty;
 import faculty.FacultyManager;
 
@@ -11,7 +14,7 @@
 public class CathedraImpl implements Cathedra {
     private String name;
     private Faculty faculty;
-
+    private Account head;
 
     protected CathedraImpl(Faculty faculty, String name) {
         this.name = name;
@@ -44,4 +47,17 @@ public void setFaculty(Faculty faculty) {
         this.faculty = faculty;
     }
 
+    @Override
+    public Account getHead() {
+        return this.head;
+    }
+
+    @Override
+    public void setHead(Account head) {
+        if (!RoleManager.getInstance().hasPermission(head, Permission.InCathedra))
+            throw new RuntimeException("Данный аккаунт не может быть заведующим кафедры.");
+
+        this.head = head;
+    }
+
 }