refact.

Yavsc.Server/Models/Workflow/Process/Negation.cs

@@ -0,0 +1,16 @@
+
+namespace Yavsc.Models.Process
+{
+    public class Negation<Exp> : IRequisition where Exp : IRequisition
+    {
+        Exp _expression;
+        public Negation(Exp expression)
+        {
+            _expression = expression;
+        }
+        public bool Eval()
+        {
+            return !_expression.Eval();
+        }
+    }
+}