Checkstyle

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

@@ -34,13 +34,12 @@ public abstract class Coach extends RollingStock {
      * @param length length of coach
      * @param couplingFront whether the coach should have a front coupling
      * @param couplingBack whether the coach should have a back coupling
-     * @throws InvalidInputException on invalid user input (zero-sized coach)
+     * @throws InvalidInputException on invalid user input (e.g. zero-sized coach)
-     * @throws IllegalArgumentException if the identifier is not positive
      */
     public Coach(int identifier, int length, boolean couplingFront, boolean couplingBack) throws InvalidInputException {
         super(length, couplingFront, couplingBack);
         if (identifier < 1) {
-            throw new IllegalArgumentException("coach id has to be positive!");
+            throw new InvalidInputException("coach id has to be positive!");
         }
         this.identifier = identifier;
     }

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

@@ -51,7 +51,7 @@ public abstract class Engine extends RollingStock {
 
     @Override
     public String getIdentifier() {
-        return String.format("%s-%s", series, getName());
+        return String.format("%s-%s", series, name);
     }
 
     @Override
@@ -84,7 +84,7 @@ public abstract class Engine extends RollingStock {
      */
     @Override
     public String toString() {
-        return String.format("%s %s %s %d %b %b", getType(), getSeries(), getName(), getLength(),
+        return String.format("%s %s %s %d %b %b", getType(), series, name, getLength(),
                 hasCouplingFront(), hasCouplingBack());
     }
 }

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

@@ -237,8 +237,7 @@ public class ModelRailwaySimulation {
             if (engine != null) {
                 return Optional.of(engine);
             }
-            final TrainSet trainSet = trainSets.get(id);
+            return Optional.ofNullable(trainSets.get(id));
-            return Optional.ofNullable(trainSet);
         }
     }
 
@@ -317,7 +316,7 @@ public class ModelRailwaySimulation {
      * Move the trains in this simulation.
      *
      * @param speed amount of steps to move the trains
-     * @return train collisions, empty if no trains are placed
+     * @return train collisions, no value if no trains are placed
      * @throws InvalidInputException if the simulation is not yet ready
      */
     public Optional<List<SortedSet<Integer>>> step(short speed) throws InvalidInputException {

src/edu/kit/informatik/modelrailwaysimulator/model/Rail.java

@@ -123,6 +123,8 @@ public abstract class Rail {
     public abstract Vector2D move(Vector2D position, Vector2D direction, long steps);
 
     /**
+     * Check whether this rail is ready for usage by trains.
+     *
      * @return whether the rail is ready for trains running on it
      */
     public abstract boolean isReadyForTrains();

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

@@ -8,7 +8,7 @@ import edu.kit.informatik.modelrailwaysimulator.ui.InvalidInputException;
  * @author Arne Keller
  * @version 1.0
  */
-public abstract class RollingStock implements Comparable<RollingStock> {
+public abstract class RollingStock {
     /**
      * Length of this rolling stock.
      */
@@ -96,15 +96,4 @@ public abstract class RollingStock implements Comparable<RollingStock> {
      * @return textual description of this rolling stock
      */
     public abstract String description();
-
-    /**
-     * Compare two rolling stocks based on their textual identifier.
-     *
-     * @param other rolling stock to compare to
-     * @return lexicographic comparison of the identifiers
-     */
-    @Override
-    public int compareTo(RollingStock other) {
-        return this.getIdentifier().compareTo(other.getIdentifier());
-    }
 }

src/edu/kit/informatik/modelrailwaysimulator/model/Switch.java

@@ -62,6 +62,12 @@ public final class Switch extends Rail {
         return rail.canConnectToRail(positionOne) || rail.canConnectToRail(positionTwo);
     }
 
+    /**
+     * Reconfigure this switch. Allows setting the same position again.
+     *
+     * @param position point to connect to
+     * @return whether switching was successful
+     */
     @Override
     public boolean switchTo(Vector2D position) {
         if (positionOne.canConnectTo(position)) {
@@ -84,7 +90,7 @@ public final class Switch extends Rail {
 
     /**
      * @param position the point to check
-     * @return whether the active switch configuration contains that position
+     * @return whether the active switch configuration {@link Track#contains(Vector2D) contains} that position
      */
     @Override
     public boolean contains(Vector2D position) {
@@ -129,7 +135,7 @@ public final class Switch extends Rail {
         if (selection == null) {
             return String.format("s %d %s -> %s,%s", getIdentifier(),
                     positionOne.getStart(), positionOne.getEnd(), positionTwo.getEnd());
-        } else {
+        } else { // print length of active segment
             return String.format("s %d %s -> %s,%s %d", getIdentifier(),
                     positionOne.getStart(), positionOne.getEnd(), positionTwo.getEnd(), getLength());
         }
@@ -153,6 +159,7 @@ public final class Switch extends Rail {
 
     @Override
     public int hashCode() {
+        // consistent with equals: ignores current configuration
         return Objects.hash(positionOne, positionTwo);
     }
 }

src/edu/kit/informatik/modelrailwaysimulator/model/Track.java

@@ -74,15 +74,19 @@ public final class Track extends Rail {
 
     @Override
     public Vector2D move(Vector2D position, Vector2D direction, long steps) {
+        if (!connectsTo(position) && !contains(position)) {
+            return null;
+        }
+        // attempt to move exactly in the specified direction
         final Vector2D nextPosition = position.add(direction.scale(steps));
         if (contains(nextPosition) || connectsTo(nextPosition)) {
             return nextPosition;
         } else if (direction.equals(getDirectionFrom(start))) {
-            return end;
+            return end; // can not go further than end of rail
         } else if (direction.equals(getDirectionFrom(end))) {
             return start;
         } else if (position.equals(end) && !direction.equals(getDirectionFrom(start))) {
-            return move(position, getDirectionFrom(end), steps);
+            return move(position, getDirectionFrom(end), steps); // attempt to correct direction
         } else if (position.equals(start) && !direction.equals(getDirectionFrom(end))) {
             return move(position, getDirectionFrom(start), steps);
         }

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

@@ -219,13 +219,55 @@ public final class Train implements Comparable<Train> {
         return new HashSet<>(occupiedRails);
     }
 
+    /**
+     * Move this train one step forward.
+     *
+     * @param railNetwork railway network to move on
+     * @return new position, null if derailing
+     */
+    public Vector2D stepForward(RailwayNetwork railNetwork) {
+        final Vector2D position = getFrontPosition();
+        final Vector2D direction = getDirection();
+        final Vector2D nextPosition = railNetwork.move(position, direction, 1);
+        if (nextPosition == null || nextPosition.equals(position)) {
+            // train is derailing
+            moveTo(railNetwork, null);
+            return null;
+        } else {
+            // train is moving successfully
+            moveTo(railNetwork, nextPosition);
+            return nextPosition;
+        }
+    }
+
+    /**
+     * Move this train one step backward.
+     *
+     * @param railNetwork railway network to move on
+     * @return new position, null if derailing
+     */
+    public Vector2D stepBackward(RailwayNetwork railNetwork) {
+        final Vector2D position = getRearPosition();
+        final Vector2D direction = getRearDirection();
+        final Vector2D nextPosition = railNetwork.move(position, direction, 1);
+        if (nextPosition == null || nextPosition.equals(position)) {
+            // derailing
+            moveBackTo(railNetwork, null);
+            return null;
+        } else {
+            // train moving successfully
+            moveBackTo(railNetwork, nextPosition);
+            return nextPosition;
+        }
+    }
+
     /**
      * Move this train on a train network to the specified position. Will not remove itself from rails if derailing.
      *
      * @param railNetwork rail network to move train on
      * @param nextPosition position to move train to
      */
-    public void moveTo(RailwayNetwork railNetwork, Vector2D nextPosition) {
+    private void moveTo(RailwayNetwork railNetwork, Vector2D nextPosition) {
         final Optional<Rail> railUnderBackOfTrain = railNetwork.findContainingRail(positions.getLast());
         positions.set(positions.size() - 1, positions.getLast().subtract(getRearDirection()));
         if (positions.getLast().equals(positions.get(positions.size() - 2))) { // left a rail behind
@@ -247,7 +289,7 @@ public final class Train implements Comparable<Train> {
      * @param railNetwork rail network to move train on
      * @param backPosition position to move back of the train to
      */
-    public void moveBackTo(RailwayNetwork railNetwork, Vector2D backPosition) {
+    private void moveBackTo(RailwayNetwork railNetwork, Vector2D backPosition) {
         // a common method for both directions would be a huge mess: requires at least six (!) extra parameters
         final Optional<Rail> railUnderFrontOfTrain = railNetwork.findContainingRail(positions.getFirst());
         positions.set(0, positions.getFirst().subtract(getDirection()));

src/edu/kit/informatik/modelrailwaysimulator/model/TrainManager.java

@@ -14,6 +14,7 @@ import java.util.SortedMap;
 import java.util.SortedSet;
 import java.util.TreeMap;
 import java.util.TreeSet;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
@@ -280,45 +281,13 @@ public final class TrainManager {
      *
      * @return list of collisions (never null, sometimes empty)
      */
-    private List<SortedSet<Train>> getCollisionsOfOneStep() {
+    private List<SortedSet<Train>> getCollisionsOfOneStep(Function<Train, Vector2D> movementFunction) {
         final List<SortedSet<Train>> collisions = new ArrayList<>();
         trains.values().stream().filter(Train::isPlaced).forEach(train -> {
-            final Vector2D position = train.getFrontPosition();
+            final Vector2D nextPosition = movementFunction.apply(train);
-            final Vector2D direction = train.getDirection();
+            if (nextPosition == null) {
-            final Vector2D nextPosition = railNetwork.move(position, direction, 1);
-            if (nextPosition == null || nextPosition.equals(position)) {
                 // train is derailing
-                train.moveTo(railNetwork, null);
                 collisions.add(Stream.of(train).collect(Collectors.toCollection(TreeSet::new)));
-            } else {
-                // train is moving successfully
-                train.moveTo(railNetwork, nextPosition);
-            }
-        });
-        getStaticCollisions(collisions);
-        collisions.forEach(collision -> collision.forEach(Train::removeFromRails));
-        return collisions;
-    }
-
-    /**
-     * Get collisions of moving the trains one step backward, removing crashing trains from the rails in the process.
-     *
-     * @return list of collisions (never null, sometimes empty)
-     */
-    private List<SortedSet<Train>> getCollisionsOfOneReverseStep() {
-        final List<SortedSet<Train>> collisions = new ArrayList<>();
-        // perform step
-        trains.values().stream().filter(Train::isPlaced).forEach(train -> {
-            final Vector2D position = train.getRearPosition();
-            final Vector2D direction = train.getRearDirection();
-            final Vector2D nextPosition = railNetwork.move(position, direction, 1);
-            if (nextPosition == null || nextPosition.equals(position)) {
-                // derailing
-                train.moveBackTo(railNetwork, nextPosition);
-                collisions.add(Stream.of(train).collect(Collectors.toCollection(TreeSet::new)));
-            } else {
-                // train moving successfully
-                train.moveBackTo(railNetwork, nextPosition);
             }
         });
         getStaticCollisions(collisions);
@@ -330,7 +299,7 @@ public final class TrainManager {
      * Move the trains in this simulation.
      *
      * @param speed amount of steps to move the trains
-     * @return train collisions, empty if no trains are placed
+     * @return train collisions, no value if no trains are placed
      * @throws InvalidInputException if simulation is not yet ready
      */
     public Optional<List<SortedSet<Integer>>> step(short speed) throws InvalidInputException {
@@ -342,11 +311,14 @@ public final class TrainManager {
         }
 
         return Optional.of(IntStream.range(0, Math.abs(speed))
-                .mapToObj(step -> speed >= 0 ? getCollisionsOfOneStep() : getCollisionsOfOneReverseStep())
+                .mapToObj(step -> speed >= 0
+                        ? getCollisionsOfOneStep(train -> train.stepForward(railNetwork))
+                        : getCollisionsOfOneStep(train -> train.stepBackward(railNetwork)))
                 // replace train references with identifiers to prevent modification by caller
                 .flatMap(collisions -> collisions.stream()
                         .map(collision -> collision.stream().map(Train::getIdentifier)
                                 .collect(Collectors.toCollection(TreeSet::new))))
+                // sort by train with lowest identifier in crash
                 .sorted(Comparator.comparing(TreeSet::first))
                 .collect(Collectors.toList()));
     }

src/edu/kit/informatik/modelrailwaysimulator/ui/command/DeleteRollingStock.java

@@ -2,12 +2,12 @@ package edu.kit.informatik.modelrailwaysimulator.ui.command;
 
 import edu.kit.informatik.modelrailwaysimulator.model.ModelRailwaySimulation;
 import edu.kit.informatik.Terminal;
+import edu.kit.informatik.modelrailwaysimulator.ui.CommandLine;
 import edu.kit.informatik.modelrailwaysimulator.ui.InvalidInputException;
 
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import static edu.kit.informatik.modelrailwaysimulator.ui.CommandLine.OK;
 import static edu.kit.informatik.modelrailwaysimulator.ui.command.CommandFactory.ROLLING_STOCK_IDENTIFIER;
 
 /**
@@ -34,7 +34,7 @@ public class DeleteRollingStock extends Command {
             throw new IllegalStateException("command not initialized");
         }
         if (simulation.deleteRollingStock(id)) {
-            Terminal.printLine(OK);
+            Terminal.printLine(CommandLine.OK);
         } else {
             Terminal.printError("could not delete rolling stock");
         }

src/edu/kit/informatik/modelrailwaysimulator/ui/command/DeleteTrack.java

@@ -2,9 +2,9 @@ package edu.kit.informatik.modelrailwaysimulator.ui.command;
 
 import edu.kit.informatik.modelrailwaysimulator.model.ModelRailwaySimulation;
 import edu.kit.informatik.Terminal;
+import edu.kit.informatik.modelrailwaysimulator.ui.CommandLine;
 import edu.kit.informatik.modelrailwaysimulator.ui.InvalidInputException;
 
-import static edu.kit.informatik.modelrailwaysimulator.ui.CommandLine.OK;
 import static edu.kit.informatik.modelrailwaysimulator.ui.command.CommandFactory.NUMBER;
 
 /**
@@ -27,7 +27,7 @@ public class DeleteTrack extends Command {
     @Override
     public void apply(ModelRailwaySimulation simulation) {
         if (simulation.removeRail(id)) {
-            Terminal.printLine(OK);
+            Terminal.printLine(CommandLine.OK);
         } else {
             Terminal.printError("could not delete rail segment");
         }

src/edu/kit/informatik/modelrailwaysimulator/ui/command/DeleteTrain.java

@@ -2,9 +2,9 @@ package edu.kit.informatik.modelrailwaysimulator.ui.command;
 
 import edu.kit.informatik.modelrailwaysimulator.model.ModelRailwaySimulation;
 import edu.kit.informatik.Terminal;
+import edu.kit.informatik.modelrailwaysimulator.ui.CommandLine;
 import edu.kit.informatik.modelrailwaysimulator.ui.InvalidInputException;
 
-import static edu.kit.informatik.modelrailwaysimulator.ui.CommandLine.OK;
 import static edu.kit.informatik.modelrailwaysimulator.ui.command.CommandFactory.NUMBER;
 
 /**
@@ -27,7 +27,7 @@ public class DeleteTrain extends Command {
     @Override
     public void apply(ModelRailwaySimulation simulation) {
         if (simulation.deleteTrain(id)) {
-            Terminal.printLine(OK);
+            Terminal.printLine(CommandLine.OK);
         } else {
             Terminal.printError("could not remove train");
         }

src/edu/kit/informatik/modelrailwaysimulator/ui/command/PutTrain.java

@@ -3,12 +3,12 @@ package edu.kit.informatik.modelrailwaysimulator.ui.command;
 import edu.kit.informatik.modelrailwaysimulator.model.ModelRailwaySimulation;
 import edu.kit.informatik.modelrailwaysimulator.model.Vector2D;
 import edu.kit.informatik.Terminal;
+import edu.kit.informatik.modelrailwaysimulator.ui.CommandLine;
 import edu.kit.informatik.modelrailwaysimulator.ui.InvalidInputException;
 
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import static edu.kit.informatik.modelrailwaysimulator.ui.CommandLine.OK;
 import static edu.kit.informatik.modelrailwaysimulator.ui.command.CommandFactory.NUMBER;
 import static edu.kit.informatik.modelrailwaysimulator.ui.command.CommandFactory.VECTOR;
 
@@ -45,7 +45,7 @@ public class PutTrain extends Command {
             throw new IllegalStateException("command not initialized");
         }
         if (simulation.putTrain(id, point, direction)) {
-            Terminal.printLine(OK);
+            Terminal.printLine(CommandLine.OK);
         } else {
             Terminal.printError("could not place train");
         }

src/edu/kit/informatik/modelrailwaysimulator/ui/command/SetSwitch.java

@@ -3,12 +3,12 @@ package edu.kit.informatik.modelrailwaysimulator.ui.command;
 import edu.kit.informatik.modelrailwaysimulator.model.ModelRailwaySimulation;
 import edu.kit.informatik.modelrailwaysimulator.model.Vector2D;
 import edu.kit.informatik.Terminal;
+import edu.kit.informatik.modelrailwaysimulator.ui.CommandLine;
 import edu.kit.informatik.modelrailwaysimulator.ui.InvalidInputException;
 
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import static edu.kit.informatik.modelrailwaysimulator.ui.CommandLine.OK;
 import static edu.kit.informatik.modelrailwaysimulator.ui.command.CommandFactory.NUMBER;
 import static edu.kit.informatik.modelrailwaysimulator.ui.command.CommandFactory.VECTOR;
 
@@ -41,7 +41,7 @@ public class SetSwitch extends Command {
             throw new IllegalStateException("command not initialized");
         }
         if (simulation.setSwitch(id, point)) {
-            Terminal.printLine(OK);
+            Terminal.printLine(CommandLine.OK);
         } else {
             Terminal.printError("could not set switch");
         }

src/edu/kit/informatik/modelrailwaysimulator/ui/command/Step.java

@@ -3,13 +3,13 @@ package edu.kit.informatik.modelrailwaysimulator.ui.command;
 import edu.kit.informatik.Terminal;
 import edu.kit.informatik.modelrailwaysimulator.model.ModelRailwaySimulation;
 import edu.kit.informatik.modelrailwaysimulator.model.Vector2D;
+import edu.kit.informatik.modelrailwaysimulator.ui.CommandLine;
 import edu.kit.informatik.modelrailwaysimulator.ui.InvalidInputException;
 
 import java.util.List;
 import java.util.Optional;
 import java.util.SortedSet;
 
-import static edu.kit.informatik.modelrailwaysimulator.ui.CommandLine.OK;
 import static edu.kit.informatik.modelrailwaysimulator.ui.command.CommandFactory.NUMBER;
 
 /**
@@ -33,7 +33,7 @@ public class Step extends Command {
     public void apply(ModelRailwaySimulation simulation) throws InvalidInputException {
         final Optional<List<SortedSet<Integer>>> collisions = simulation.step(speed);
         if (!collisions.isPresent()) {
-            Terminal.printLine(OK);
+            Terminal.printLine(CommandLine.OK);
         } else {
             for (final int id : simulation.getTrains().keySet()) {
                 final SortedSet<Integer> collisionSet = collisions.get().stream()