SEC-2187: Polish

Create private utf8UrlEncode method to improve readability

openid/src/main/java/org/springframework/security/openid/OpenIDAuthenticationFilter.java

@@ -188,7 +188,6 @@ public class OpenIDAuthenticationFilter extends AbstractAuthenticationProcessing
      * @return The <tt>return_to</tt> URL.
      */
     protected String buildReturnToUrl(HttpServletRequest request) {
-        try {
         StringBuffer sb = request.getRequestURL();
 
         Iterator<String> iterator = returnToUrlParameters.iterator();
@@ -207,18 +206,13 @@ public class OpenIDAuthenticationFilter extends AbstractAuthenticationProcessing
                 sb.append("?");
                 isFirst = false;
             }
-                sb.append(URLEncoder.encode(name, "UTF-8")).append("=").append(URLEncoder.encode(value, "UTF-8"));
+            sb.append(utf8UrlEncode(name)).append("=").append(utf8UrlEncode(value));
 
             if (iterator.hasNext()) {
                 sb.append("&");
             }
         }
         return sb.toString();
-        } catch(UnsupportedEncodingException e) {
-            Error err = new AssertionError("The Java platform guarantees UTF-8 support, but it seemingly is not present.");
-            err.initCause(e);
-            throw err;
-        }
     }
 
     /**
@@ -276,4 +270,20 @@ public class OpenIDAuthenticationFilter extends AbstractAuthenticationProcessing
         Assert.notNull(returnToUrlParameters, "returnToUrlParameters cannot be null");
         this.returnToUrlParameters = returnToUrlParameters;
     }
+
+    /**
+     * Performs URL encoding with UTF-8
+     *
+     * @param value the value to URL encode
+     * @return the encoded value
+     */
+    private String utf8UrlEncode(String value) {
+        try {
+            return URLEncoder.encode(value, "UTF-8");
+        } catch(UnsupportedEncodingException e) {
+            Error err = new AssertionError("The Java platform guarantees UTF-8 support, but it seemingly is not present.");
+            err.initCause(e);
+            throw err;
+        }
+    }
 }