bug 10094: distinguish between no transition from one state to another vs there's a concurrent operation

utils/src/com/cloud/utils/fsm/NoTransitionException.java

@@ -0,0 +1,34 @@
+/**
+ *  Copyright (C) 2010 Cloud.com, Inc.  All rights reserved.
+ * 
+ * This software is licensed under the GNU General Public License v3 or later.
+ * 
+ * It is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or any later version.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * 
+ */
+package com.cloud.utils.fsm;
+
+import com.cloud.utils.SerialVersionUID;
+
+/**
+ * Thrown by the state machine when there is no transition from one state
+ * to another.
+ *
+ */
+public class NoTransitionException extends Exception {
+    
+    private static final long serialVersionUID = SerialVersionUID.NoTransitionException;
+    
+    public NoTransitionException(String msg) {
+        super(msg);
+    }
+}