Add UserExistsMiddleware - ConcreteHandler (Filtering Access - Chain …

…Of Responsibility)

ChainOfResponsability/FilteringAccess/UserExistsMiddleware.java

@@ -0,0 +1,29 @@
+// ConcreteHandler
+public class UserExistsMiddleware extends BaseMiddleware{
+    private Server server;
+
+    //! Constructor replaced by link method
+    //public UserExistsMiddleware(BaseMiddleware m){
+     //   this.next = m;
+    //}
+
+    public UserExistsMiddleware(Server s) {
+        this.server = s;
+    }
+
+    // handlerRequest method
+    @Override
+    public boolean check(String email, String password) {
+        if(!server.hasEmail(email)){
+            System.out.println("This email is not registered");
+            return false;
+        }
+        if (!server.isValidPassword(email, password)) {
+            System.out.println("Wrong password");
+            return false;
+        }
+
+        return checkNext(email, password);
+    }
+}
+