Bugfixes: Null pointer exceptions on null attributes

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

@@ -65,7 +65,7 @@ public abstract class DataProcessor<K extends DataKey<K>, V> {
 	}
 
 	public AttributesProcessor getAttributes() {
-		return this.attributes;
+		return attributes;
 	}
 
 	public void setAttributes(AttributesProcessor attributes) {
@@ -122,7 +122,8 @@ public abstract class DataProcessor<K extends DataKey<K>, V> {
 	}
 
 	public void sealAttributes() {
-		attributes.seal();
+		if (attributes != null) // some processors might not have attributes
+			attributes.seal();
 	}
 
 }

VadereState/src/org/vadere/state/scenario/Topography.java

@@ -72,6 +72,7 @@ public class Topography {
 		allOtherAttributes.add(attributes);
 		allOtherAttributes.add(attributesCar);
 		allOtherAttributes.add(attributesPedestrian);
+		removeNullAttributes();
 
 		obstacles = new LinkedList<>();
 		stairs = new LinkedList<>();
@@ -92,6 +93,15 @@ public class Topography {
 		
 	}
 
+	/** Clean up the list of attributes by removing {@code null}. */
+	private void removeNullAttributes() {
+		allOtherAttributes.remove(null);
+		// Actually, only attributes, not nulls should be added to this set.
+		// But sometimes null is passed as attributes and added to the set,
+		// although it is bad practice to pass null in the first place
+		// (as constructor argument).
+	}
+
 	/**
 	 * Creates an empty scenario where bounds and finishTime are empty / zero.
 	 */