--- /dev/null
+package psgsim;
+
+/**
+ * An interface which defines a size for the message or the event to be sent. If you
+ * wish that your message has a size, your class message must implements this
+ * interface and defines a size parameter in the constructor.
+ *
+ * @author Khaled Baati 05/02/2015
+ * @version 1.1
+ *
+ */
+public interface Sizable {
+ /**
+ *
+ * @return The size of the message
+ */
+ public double getSize();
+}