diff --git a/websocket-sharp/Net/EndPointManager.cs b/websocket-sharp/Net/EndPointManager.cs
index fa92a7af..e24c7aa5 100644
--- a/websocket-sharp/Net/EndPointManager.cs
+++ b/websocket-sharp/Net/EndPointManager.cs
@@ -81,7 +81,7 @@ namespace WebSocketSharp.Net
         throw new HttpListenerException (400, "Invalid path."); // TODO: Code?
 
       // Always listens on all the interfaces, no matter the host name/ip used.
-      var epl = getEndPointListener (IPAddress.Any, pref.Port, pref.Secure, httpListener);
+      var epl = getEndPointListener (IPAddress.Any, pref.Port, pref.IsSecure, httpListener);
       epl.AddPrefix (pref, httpListener);
     }
 
@@ -124,7 +124,7 @@ namespace WebSocketSharp.Net
       if (pref.Path.IndexOf ("//", StringComparison.Ordinal) != -1)
         return;
 
-      var epl = getEndPointListener (IPAddress.Any, pref.Port, pref.Secure, httpListener);
+      var epl = getEndPointListener (IPAddress.Any, pref.Port, pref.IsSecure, httpListener);
       epl.RemovePrefix (pref, httpListener);
     }
 
diff --git a/websocket-sharp/Net/ListenerPrefix.cs b/websocket-sharp/Net/ListenerPrefix.cs
index 1ead612e..044eebb0 100644
--- a/websocket-sharp/Net/ListenerPrefix.cs
+++ b/websocket-sharp/Net/ListenerPrefix.cs
@@ -47,8 +47,9 @@ namespace WebSocketSharp.Net
   {
     #region Private Fields
 
-    IPAddress [] _addresses;
+    IPAddress[]  _addresses;
     string       _host;
+    HttpListener _listener;
     string       _original;
     string       _path;
     ushort       _port;
@@ -56,12 +57,6 @@ namespace WebSocketSharp.Net
 
     #endregion
 
-    #region Public Fields
-
-    public HttpListener Listener;
-
-    #endregion
-
     #region Public Constructors
 
     // Must be called after calling ListenerPrefix.CheckUriPrefix.
@@ -75,7 +70,7 @@ namespace WebSocketSharp.Net
 
     #region Public Properties
 
-    public IPAddress [] Addresses {
+    public IPAddress[] Addresses {
       get {
         return _addresses;
       }
@@ -91,6 +86,22 @@ namespace WebSocketSharp.Net
       }
     }
 
+    public bool IsSecure {
+      get {
+        return _secure;
+      }
+    }
+
+    public HttpListener Listener {
+      get {
+        return _listener;
+      }
+
+      set {
+        _listener = value;
+      }
+    }
+
     public string Path {
       get {
         return _path;
@@ -103,12 +114,6 @@ namespace WebSocketSharp.Net
       }
     }
 
-    public bool Secure {
-      get {
-        return _secure;
-      }
-    }
-
     #endregion
 
     #region Private Methods
@@ -119,25 +124,25 @@ namespace WebSocketSharp.Net
       if (defaultPort == 443)
         _secure = true;
 
-      var length = uriPrefix.Length;
+      var len = uriPrefix.Length;
       var startHost = uriPrefix.IndexOf (':') + 3;
-      var colon = uriPrefix.IndexOf (':', startHost, length - startHost);
-      int root;
+      var colon = uriPrefix.IndexOf (':', startHost, len - startHost);
+      var root = 0;
       if (colon > 0) {
-        root = uriPrefix.IndexOf ('/', colon, length - colon);
+        root = uriPrefix.IndexOf ('/', colon, len - colon);
         _host = uriPrefix.Substring (startHost, colon - startHost);
         _port = (ushort) Int32.Parse (uriPrefix.Substring (colon + 1, root - colon - 1));
-        _path = uriPrefix.Substring (root);
       }
       else {
-        root = uriPrefix.IndexOf ('/', startHost, length - startHost);
+        root = uriPrefix.IndexOf ('/', startHost, len - startHost);
         _host = uriPrefix.Substring (startHost, root - startHost);
         _port = (ushort) defaultPort;
-        _path = uriPrefix.Substring (root);
       }
 
-      if (_path.Length > 1)
-        _path = _path.Substring (0, _path.Length - 1);
+      _path = uriPrefix.Substring (root);
+      var pathLen = _path.Length;
+      if (pathLen > 1)
+        _path = _path.Substring (0, pathLen - 1);
     }
 
     #endregion
@@ -149,46 +154,46 @@ namespace WebSocketSharp.Net
       if (uriPrefix == null)
         throw new ArgumentNullException ("uriPrefix");
 
-      if (!uriPrefix.StartsWith ("http://") && !uriPrefix.StartsWith ("https://"))
-        throw new ArgumentException ("Only 'http' and 'https' schemes are supported.");
+      var len = uriPrefix.Length;
+      if (len == 0)
+        throw new ArgumentException ("An empty string.");
+
+      if (!(uriPrefix.StartsWith ("http://") || uriPrefix.StartsWith ("https://")))
+        throw new ArgumentException ("The scheme isn't 'http' or 'https'.");
 
-      var length = uriPrefix.Length;
       var startHost = uriPrefix.IndexOf (':') + 3;
-      if (startHost >= length)
-        throw new ArgumentException ("No host specified.");
+      if (startHost >= len)
+        throw new ArgumentException ("No host is specified.");
 
-      var colon = uriPrefix.IndexOf (':', startHost, length - startHost);
+      var colon = uriPrefix.IndexOf (':', startHost, len - startHost);
       if (startHost == colon)
-        throw new ArgumentException ("No host specified.");
+        throw new ArgumentException ("No host is specified.");
 
-      int root;
       if (colon > 0) {
-        root = uriPrefix.IndexOf ('/', colon, length - colon);
+        var root = uriPrefix.IndexOf ('/', colon, len - colon);
         if (root == -1)
-          throw new ArgumentException ("No path specified.");
+          throw new ArgumentException ("No path is specified.");
 
         int port;
         if (!Int32.TryParse (uriPrefix.Substring (colon + 1, root - colon - 1), out port) ||
-            (port <= 0 || port >= 65536))
-          throw new ArgumentException ("Invalid port.");
+            !port.IsPortNumber ())
+          throw new ArgumentException ("An invalid port is specified.");
       }
       else {
-        root = uriPrefix.IndexOf ('/', startHost, length - startHost);
+        var root = uriPrefix.IndexOf ('/', startHost, len - startHost);
         if (root == -1)
-          throw new ArgumentException ("No path specified.");
+          throw new ArgumentException ("No path is specified.");
       }
 
-      if (uriPrefix [uriPrefix.Length - 1] != '/')
-        throw new ArgumentException ("The URI prefix must end with '/'.");
+      if (uriPrefix[len - 1] != '/')
+        throw new ArgumentException ("Ends without '/'.");
     }
 
     // Equals and GetHashCode are required to detect duplicates in HttpListenerPrefixCollection.
-    public override bool Equals (object obj)
+    public override bool Equals (Object obj)
     {
-      var other = obj as ListenerPrefix;
-      return other != null
-             ? _original == other._original
-             : false;
+      var pref = obj as ListenerPrefix;
+      return pref != null && pref._original == _original;
     }
 
     public override int GetHashCode ()