From 34b5f5c38b206e682732835ec35b4df589ad7af3 Mon Sep 17 00:00:00 2001
From: Axel Uhl <axel.uhl@sap.com>
Date: Mon, 2 Jan 2012 15:52:04 +0100
Subject: [PATCH] getEstimatedPosition now returns null if no relevant fix is
 found

---
 .../impl/DynamicGPSFixMovingTrackImpl.java     |  2 +-
 .../domain/tracking/impl/GPSFixTrackImpl.java  | 18 +++++++++++++-----
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/DynamicGPSFixMovingTrackImpl.java b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/DynamicGPSFixMovingTrackImpl.java
index 4a9262be32e..b6ee6d614c4 100755
--- a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/DynamicGPSFixMovingTrackImpl.java
+++ b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/DynamicGPSFixMovingTrackImpl.java
@@ -64,7 +64,7 @@ public class DynamicGPSFixMovingTrackImpl<ItemType> extends DynamicTrackImpl<Ite
                 last = next;
             }
         }
-        SpeedWithBearing avgSpeed = new KnotSpeedWithBearingImpl(knotSum / count, bearingCluster.getAverage());
+        SpeedWithBearing avgSpeed = count == 0 ? null : new KnotSpeedWithBearingImpl(knotSum / count, bearingCluster.getAverage());
         return avgSpeed;
     }
     
diff --git a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/GPSFixTrackImpl.java b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/GPSFixTrackImpl.java
index 5707f4efc2a..0126429f51f 100755
--- a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/GPSFixTrackImpl.java
+++ b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/GPSFixTrackImpl.java
@@ -324,7 +324,7 @@ public class GPSFixTrackImpl<ItemType, FixType extends GPSFix> extends TrackImpl
                 last = next;
             }
         }
-        SpeedWithBearing avgSpeed = new KnotSpeedWithBearingImpl(knotSum / count, bearingCluster.getAverage());
+        SpeedWithBearing avgSpeed = count == 0 ? null : new KnotSpeedWithBearingImpl(knotSum / count, bearingCluster.getAverage());
         return avgSpeed;
     }
 
@@ -420,12 +420,20 @@ public class GPSFixTrackImpl<ItemType, FixType extends GPSFix> extends TrackImpl
 
     @Override
     public boolean hasDirectionChange(TimePoint at, double minimumDegreeDifference) {
+        boolean result = false;
         TimePoint start = new MillisecondsTimePoint(at.asMillis()-getMillisecondsOverWhichToAverageSpeed());
         TimePoint end = new MillisecondsTimePoint(at.asMillis()+getMillisecondsOverWhichToAverageSpeed());
-        Bearing bearingAtStart = getEstimatedSpeed(start).getBearing();
-        Bearing bearingAtEnd = getEstimatedSpeed(end).getBearing();
-        // TODO also need to analyze the (smoothened) directions in between; example: two tacks within averaging interval
-        return Math.abs(bearingAtStart.getDifferenceTo(bearingAtEnd).getDegrees()) > minimumDegreeDifference;
+        SpeedWithBearing estimatedSpeedAtStart = getEstimatedSpeed(start);
+        if (estimatedSpeedAtStart != null) {
+            Bearing bearingAtStart = estimatedSpeedAtStart.getBearing();
+            SpeedWithBearing estimatedSpeedAtEnd = getEstimatedSpeed(end);
+            if (estimatedSpeedAtEnd != null) {
+                Bearing bearingAtEnd = estimatedSpeedAtEnd.getBearing();
+                // TODO also need to analyze the (smoothened) directions in between; example: two tacks within averaging interval
+                result = Math.abs(bearingAtStart.getDifferenceTo(bearingAtEnd).getDegrees()) > minimumDegreeDifference;
+            }
+        }
+        return result;
     }
 
 }