From 51663793c1fbabd71840f9a086c7f354c6d573c8 Mon Sep 17 00:00:00 2001
From: sta <sta.blockhead@gmail.com>
Date: Mon, 7 Aug 2017 15:56:22 +0900
Subject: [PATCH] [Modify] Throw exceptions

---
 websocket-sharp/Server/WebSocketSessionManager.cs | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/websocket-sharp/Server/WebSocketSessionManager.cs b/websocket-sharp/Server/WebSocketSessionManager.cs
index 8252ec85..1da63458 100644
--- a/websocket-sharp/Server/WebSocketSessionManager.cs
+++ b/websocket-sharp/Server/WebSocketSessionManager.cs
@@ -1052,14 +1052,17 @@ namespace WebSocketSharp.Server
     /// </param>
     public bool TryGetSession (string id, out IWebSocketSession session)
     {
-      var msg = _state.CheckIfAvailable (false, true, false) ?? id.CheckIfValidSessionID ();
-      if (msg != null) {
-        _logger.Error (msg);
-        session = null;
-
-        return false;
+      if (_state != ServerState.Start) {
+        var msg = "The current state of the manager is not Start.";
+        throw new InvalidOperationException (msg);
       }
 
+      if (id == null)
+        throw new ArgumentNullException ("id");
+
+      if (id.Length == 0)
+        throw new ArgumentException ("An empty string.", "id");
+
       return tryGetSession (id, out session);
     }