Checkstyle

src/edu/kit/informatik/model/Coach.java

@@ -41,7 +41,7 @@ public abstract class Coach extends RollingStock {
 
     @Override
     public String getIdentifier() {
-        return String.format("W%d", identifier);
+        return String.format("%s%d", IDENTIFIER_PREFIX, identifier);
     }
 
     @Override
@@ -49,6 +49,16 @@ public abstract class Coach extends RollingStock {
         return true;
     }
 
+    @Override
+    public boolean usefulAtFrontOfTrain() {
+        return false;
+    }
+
+    @Override
+    public boolean usefulAtBackOfTrain() {
+        return false;
+    }
+
     /**
      * @return the numerical identifier of this coach
      */

src/edu/kit/informatik/model/DieselEngine.java

@@ -43,7 +43,8 @@ public class DieselEngine extends Engine {
 
     @Override
     public String[] textRepresentation() {
-        return DIESEL_ENGINE_TEXT;
+        // make sure caller can not modify private data
+        return DIESEL_ENGINE_TEXT.clone();
     }
 
     @Override

src/edu/kit/informatik/model/ElectricalEngine.java

@@ -45,7 +45,8 @@ public class ElectricalEngine extends Engine {
 
     @Override
     public String[] textRepresentation() {
-        return ELECTRICAL_ENGINE_TEXT;
+        // make sure caller can not modify private data
+        return ELECTRICAL_ENGINE_TEXT.clone();
     }
 
     @Override

src/edu/kit/informatik/model/Engine.java

@@ -57,4 +57,14 @@ public abstract class Engine extends RollingStock {
     public boolean canCoupleTo(RollingStock rollingStock) {
         return true;
     }
+
+    @Override
+    public boolean usefulAtFrontOfTrain() {
+        return true;
+    }
+
+    @Override
+    public boolean usefulAtBackOfTrain() {
+        return true;
+    }
 }

src/edu/kit/informatik/model/FreightCoach.java

@@ -34,7 +34,8 @@ public class FreightCoach extends Coach {
 
     @Override
     public String[] textRepresentation() {
-        return FREIGHT_TEXT;
+        // make sure caller can not modify private data
+        return FREIGHT_TEXT.clone();
     }
 
     @Override

src/edu/kit/informatik/model/ModelRailwaySimulation.java

@@ -38,11 +38,11 @@ public class ModelRailwaySimulation {
      */
     private final List<TrainSet> trainSets = new ArrayList<>();
     /**
-     * List of coaches used in the simulation.
+     * Map of coaches used in the simulation.
      */
     private final Map<Integer, Coach> coaches = new HashMap<>();
     /**
-     * List of trains simulated.
+     * Map of trains simulated.
      */
     private final Map<Integer, Train> trains = new HashMap<>();
 

src/edu/kit/informatik/model/PassengerCoach.java

@@ -35,7 +35,8 @@ public class PassengerCoach extends Coach {
 
     @Override
     public String[] textRepresentation() {
-        return PASSENGER_TEXT;
+        // make sure caller can not modify private data
+        return PASSENGER_TEXT.clone();
     }
 
     @Override

src/edu/kit/informatik/model/RailwayNetwork.java

@@ -108,7 +108,7 @@ public class RailwayNetwork {
             return false;
         }
 
-        // locate one other rail: TODO use rail.connectedrails?
+        // locate one connected rail
         Rail otherRail = null;
         for (Rail anotherRail : rails.values()) {
             if (anotherRail.getIdentifier() != id && anotherRail.canConnectToRail(toRemove)) {

src/edu/kit/informatik/model/RollingStock.java

@@ -71,6 +71,16 @@ public abstract class RollingStock {
      */
     public abstract boolean canCoupleTo(RollingStock rollingStock);
 
+    /**
+     * @return whether this rolling stock is useful at the front end of a train
+     */
+    public abstract boolean usefulAtFrontOfTrain();
+
+    /**
+     * @return whether this rolling stock is useful at the rear end of a train
+     */
+    public abstract boolean usefulAtBackOfTrain();
+
     /**
      * @return ASCII art representation of this rolling stock
      */

src/edu/kit/informatik/model/SpecialCoach.java

@@ -36,7 +36,8 @@ public class SpecialCoach extends Coach {
 
     @Override
     public String[] textRepresentation() {
-        return SPECIAL_TEXT;
+        // make sure caller can not modify private data
+        return SPECIAL_TEXT.clone();
     }
 
     @Override

src/edu/kit/informatik/model/SteamEngine.java

@@ -43,7 +43,8 @@ public class SteamEngine extends Engine {
 
     @Override
     public String[] textRepresentation() {
-        return STEAM_ENGINE_TEXT;
+        // make sure caller can not modify private data
+        return STEAM_ENGINE_TEXT.clone();
     }
 
     @Override

src/edu/kit/informatik/model/Train.java

@@ -192,17 +192,14 @@ public final class Train {
     }
 
     /**
-     * Check whether this train is correctly set up. More specifically, it either consists of train sets or has an
-     * engine as first or last rolling stock.
+     * Check whether this train is correctly set up. More specifically, it usually either consists of train sets or has
+     * an engine as first or last rolling stock.
      * @return whether this train is valid
      */
     public boolean isProperTrain() {
         RollingStock first = rollingStocks.get(0);
         RollingStock last = rollingStocks.get(rollingStocks.size() - 1);
-        // the first or last rolling stock HAVE TO BE an engine OR a train-set!
-        // therefore, no other rolling stock types should be allowed at all.
-        // TODO: consider using first.canBeAtFront() ???
-        return first instanceof Engine || first instanceof TrainSet || last instanceof Engine;
+        return first.usefulAtFrontOfTrain() || last.usefulAtBackOfTrain();
     }
 
     /**

src/edu/kit/informatik/model/TrainSet.java

@@ -28,7 +28,7 @@ public class TrainSet extends RollingStock {
      */
     private final String series;
     /**
-     * Name of this train set. TODO: create NamedRollingStock class
+     * Name of this train set.
      */
     private final String name;
 
@@ -63,9 +63,20 @@ public class TrainSet extends RollingStock {
         return rollingStock.getClass().equals(this.getClass()) && ((TrainSet) rollingStock).series.equals(this.series);
     }
 
+    @Override
+    public boolean usefulAtFrontOfTrain() {
+        return true;
+    }
+
+    @Override
+    public boolean usefulAtBackOfTrain() {
+        return true;
+    }
+
     @Override
     public String[] textRepresentation() {
-        return TRAIN_SET_TEXT;
+        // make sure caller can not modify private data
+        return TRAIN_SET_TEXT.clone();
     }
 
     @Override