BAEL-1567 use optional

javax-servlets/src/main/java/com/baeldung/servlets/CookieReader.java

@@ -3,6 +3,7 @@
 import javax.servlet.http.Cookie;
 import javax.servlet.http.HttpServletRequest;
 import java.util.Arrays;
+import java.util.Optional;
 
 /**
  * Created by adam.
@@ -26,14 +27,13 @@ public CookieReader(HttpServletRequest request) {
      * Reads cookie by key from request.
      *
      * @param key the key of a cookie
-     * @return returns cookie value (or null if cookie with given key does not exist)
+     * @return returns cookie value
      */
-    public String readCookie(String key) {
+    public Optional<String> readCookie(String key) {
         return Arrays.stream(request.getCookies())
                  .filter(c -> key.equals(c.getName()))
                  .map(Cookie::getValue)
-                 .findFirst()
-                 .orElse(null);
+                 .findFirst();
     }
 
 }

javax-servlets/src/main/java/com/baeldung/servlets/LoginServlet.java

@@ -5,6 +5,7 @@
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.*;
 import java.io.IOException;
+import java.util.Optional;
 
 /**
  * Created by adam.
@@ -15,12 +16,12 @@ public class LoginServlet extends HttpServlet {
     @Override
     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         CookieReader cookieReader = new CookieReader(request);
-        String uiColor = cookieReader.readCookie("uiColor");
-        String userName = cookieReader.readCookie("userName");
+        Optional<String> uiColor = cookieReader.readCookie("uiColor");
+        Optional<String> userName = cookieReader.readCookie("userName");
 
-        request.setAttribute("uiColor", uiColor != null ? uiColor : "blue");
+        request.setAttribute("uiColor", uiColor.isPresent() ? uiColor.get() : "blue");
 
-        if (userName == null || userName.isEmpty()) {
+        if (!userName.isPresent()) {
             RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/jsp/login.jsp");
             dispatcher.forward(request, response);
         } else {

javax-servlets/src/main/java/com/baeldung/servlets/WelcomeServlet.java

@@ -8,6 +8,7 @@
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
+import java.util.Optional;
 
 /**
  * Created by adam.
@@ -18,15 +19,16 @@ public class WelcomeServlet extends HttpServlet {
     @Override
     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         CookieReader cookieReader = new CookieReader(request);
-        String uiColor = cookieReader.readCookie("uiColor");
-        String userName = cookieReader.readCookie("userName");
+        Optional<String> uiColor = cookieReader.readCookie("uiColor");
+        Optional<String> userName = cookieReader.readCookie("userName");
 
-        if (userName == null || userName.isEmpty()) {
+        if (!userName.isPresent()) {
             response.sendRedirect("/login");
         } else {
-            request.setAttribute("uiColor", uiColor != null ? uiColor : "blue");
-            request.setAttribute("userName", userName);
-            request.setAttribute("sessionAttribute", request.getSession().getAttribute("sampleKey"));
+            request.setAttribute("uiColor", uiColor.isPresent() ? uiColor.get() : "blue");
+            request.setAttribute("userName", userName.get());
+            request.setAttribute("sessionAttribute", request.getSession()
+                .getAttribute("sampleKey"));
 
             RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/jsp/welcome.jsp");
             dispatcher.forward(request, response);