Moved top-level cache for TrackedEvent from TracTrac-specific DomainFactory to RacingEventService;

introduced a TrackedEventRegistry interface in com.sap.sailing.domain that is now extended by
RacingEventService as well as a dummy implementation for use by tests

java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/TrackedEventRegistry.java

@@ -0,0 +1,28 @@
+package com.sap.sailing.domain.tracking;
+
+import com.sap.sailing.domain.base.Event;
+
+/**
+ * {@link TrackedEvent}s or {@link DynamicTrackedEvent}s belong to {@link Event} objects. However, an {@link Event}
+ * doesn't and shouldn't know how it's being tracked. A <em>registry</em> decouples them. Test cases may use
+ * different, simplified registries.
+ * 
+ * @author Axel Uhl (d043530)
+ *
+ */
+public interface TrackedEventRegistry {
+    /**
+     * Looks for tracking information about <code>event</code>. If no such object exists yet, a new one
+     * is created.
+     */
+    DynamicTrackedEvent getOrCreateTrackedEvent(Event event);
+
+    /**
+     * Looks for the tracking information for <code>event</code>. If not found, <code>null</code> is returned
+     * immediately. See also {@link #getOrCreateTrackedEvent(com.sap.sailing.domain.base.Event)}.
+     */
+    DynamicTrackedEvent getTrackedEvent(com.sap.sailing.domain.base.Event event);
+
+    void remove(Event event);
+
+}