#78 Test for null and replace with -1 and log this as warning

VadereSimulator/src/org/vadere/simulator/projects/dataprocessing/datakey/TimestepPedestrianIdKey.java

@@ -38,6 +38,14 @@ public class TimestepPedestrianIdKey implements DataKey<TimestepPedestrianIdKey>
 		return new String[] { TimestepKey.getHeader(), PedestrianIdKey.getHeader() };
 	}
 
+	@Override
+	public String toString() {
+		return "TimestepPedestrianIdKey{" +
+				"timestep=" + timestep +
+				", pedestrianId=" + pedestrianId +
+				'}';
+	}
+
 	@Override
 	public int hashCode() {
 		final int prime = 31;

VadereSimulator/src/org/vadere/simulator/projects/dataprocessing/processor/PedestrianGroupIDProcessor.java

 package org.vadere.simulator.projects.dataprocessing.processor;
 
+import org.apache.log4j.LogManager;
+import org.apache.log4j.Logger;
 import org.vadere.annotation.factories.dataprocessors.DataProcessorClass;
 import org.vadere.simulator.control.SimulationState;
 import org.vadere.simulator.models.MainModel;
@@ -9,10 +11,13 @@ import org.vadere.simulator.projects.dataprocessing.ProcessorManager;
 import org.vadere.simulator.projects.dataprocessing.datakey.TimestepPedestrianIdKey;
 
 import java.util.Optional;
+import java.util.Random;
 
 @DataProcessorClass
 public class PedestrianGroupIDProcessor extends DataProcessor<TimestepPedestrianIdKey, Integer>{
 
+	private static Logger logger = LogManager.getLogger(PedestrianGroupIDProcessor.class);
+
 	public PedestrianGroupIDProcessor(){
 		super("groupId");
 	}
@@ -42,6 +47,12 @@ public class PedestrianGroupIDProcessor extends DataProcessor<TimestepPedestrian
 
 	public String[] toStrings(TimestepPedestrianIdKey key){
 		Integer i = this.getValue(key);
+		if (i == null) {
+			logger.warn(String.format("PedestrianGroupIDProcessor does not has Data for Key: %s",
+					key.toString()));
+			i = -1;
+		}
+
 		return new String[]{Integer.toString(i)};
 	}
 }