+/**
+ * The listener interface for receiving signals from the
+ * {@link WebServiceWorkerI} about the state changes or new sub-jobs spawned.
+ *
+ * The {@link WebServiceWorkerListener} objects created from that interface are
+ * then registered with a worker objects using
+ * {@link WebServiceWorkerI#addListener} method. When an event occurs, a
+ * relevant method in the listener is invoked with the worker that emitted the
+ * signal as a first parameter and, optionally, followed by additional event
+ * details.
+ *
+ * @author mmwarowny
+ *
+ */