Fixed NPE due to new 5G-Entry API

src/de/tud/kom/p2psim/impl/topology/views/FiveGTopologyView.java

@@ -443,6 +443,20 @@ public class FiveGTopologyView extends AbstractTopologyView<CellLink> {
 		public void setLinkData(FiveGTopologyDatabase.Entry linkData,
 				FiveGTopologyDatabase.Entry apLinkData) {
 			
+			// Initialization
+			if (this.linkData == null && this.apLinkData == null) {
+				this.linkData = linkData;
+				this.apLinkData = apLinkData;
+				if (apLinkData != null) {
+					apLinkData.onHostEntersSegment(mobileClient);
+				} else {
+					linkData.onHostEntersSegment(mobileClient);
+				}
+				// For the first update on link creation.
+				return;
+			}
+			
+			// Update
 			if (apLinkData != null) {
 				assert supportsAccessPoints;
 				if (this.apLinkData != null) {