src/Tools/jEdit/src/utils/EventSource.scala

+package isabelle.utils
+
+import scala.collection.mutable.HashSet
+
+class EventSource[Event] {
+  private val handlers = new HashSet[(Event) => Unit]()
+
+  def add(handler : (Event) => Unit) { handlers += handler }
+  def remove(handler : (Event) => Unit) { handlers -= handler }
+	
+  def fire(event : Event) { for(h <- handlers) h(event) }
+}