implemented handling of stuck trains during route search

pom.xml

@@ -4,7 +4,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>de.srsoftware</groupId>
 	<artifactId>web4rail</artifactId>
-	<version>1.3.66</version>
+	<version>1.3.67</version>
 	<name>Web4Rail</name>
 	<packaging>jar</packaging>
 	<description>Java Model Railway Control</description>

src/main/java/de/srsoftware/web4rail/Route.java

@@ -380,7 +380,8 @@ public class Route extends BaseClass {
 	}
 	
 	private void free() {
-		context.invalidate();
+		context.invalidate(); // do not set to null: 
+		// this action may be called from route.contact → finishRoute, which calls train.updateTrace afterwards, which in turn requires context
 		Train train = context.train();
 		Vector<Tile> reversedPath = reverse(path());
 		for (Tile tile : reversedPath) {
@@ -750,6 +751,7 @@ public class Route extends BaseClass {
 		Train train = context.train();
 		free();
 		train.drop(this);
+		context = null;
 		return true;
 	}
 	

src/main/java/de/srsoftware/web4rail/moving/Train.java

@@ -90,6 +90,8 @@ public class Train extends BaseClass implements Comparable<Train> {
 	private boolean shunting = false;
 	private RouteManager routeManager = null;
 
+	private HashSet<Tile> stuckTrace = null;
+
 	public static Object action(HashMap<String, String> params, Plan plan) throws IOException {
 		String action = params.get(ACTION);
 		if (isNull(action)) return t("No action passed to Train.action!");
@@ -405,6 +407,7 @@ public class Train extends BaseClass implements Comparable<Train> {
 		endBlock.add(this, direction);		
 		currentBlock = endBlock;
 		trace.add(endBlock);
+		stuckTrace = null;
 	}
 
 	private Tag faster(int steps) {
@@ -866,10 +869,19 @@ public class Train extends BaseClass implements Comparable<Train> {
 		setSpeed(0);
 		quitAutopilot();
 		if (isSet(route)) {
+			stuckTrace = new HashSet<Tile>(); 
+			for (Tile tile : route.path()) { // collect occupied tiles of route. stuckTrace is considered during next route search
+				if (trace.contains(tile)) stuckTrace.add(tile);
+			}
 			route.reset();
 		}
 		return properties();
 	}
+	
+	public HashSet<Tile> stuckTrace() {
+		return stuckTrace;
+	}
+
 
 	public SortedSet<String> tags() {
 		TreeSet<String> list = new TreeSet<String>(tags);

src/main/java/de/srsoftware/web4rail/threads/RouteManager.java

@@ -14,6 +14,7 @@ import de.srsoftware.web4rail.Plan.Direction;
 import de.srsoftware.web4rail.Route;
 import de.srsoftware.web4rail.moving.Train;
 import de.srsoftware.web4rail.tiles.Block;
+import de.srsoftware.web4rail.tiles.Tile;
 
 public class RouteManager extends BaseClass implements Runnable {
 	
@@ -66,6 +67,13 @@ public class RouteManager extends BaseClass implements Runnable {
 				LOG.debug("{}→ Candidate {}  would create loop, skipping",inset,routeCandidate.shortName());
 				continue;
 			}
+			
+			HashSet<Tile> stuckTrace = train.stuckTrace(); // if train has been stopped in between two blocks lastly: only allow routes that do not conflict with current train position
+			if (isSet(stuckTrace) && !routeCandidate.path().containsAll(stuckTrace)) {
+				LOG.debug("Stuck train occupies tiles ({}) outside of {} – not allowed.",stuckTrace,routeCandidate);
+				continue;
+			}
+			
 			if (!routeCandidate.allowed(context)) { 
 				if (routeCandidate.endBlock() != destination) { // allowance may be overridden by destination
 					LOG.debug("{} not allowed for {}",routeCandidate,context);

src/main/java/de/srsoftware/web4rail/tiles/Block.java

@@ -278,8 +278,9 @@ public abstract class Block extends StretchableTile{
 		if (isNull(firstTrain)) return true;
 		if (firstTrain != train) return false;
 		trains.remove(train);
-		status = trains.isEmpty() ? Status.FREE : Status.OCCUPIED;
-		plan.place(this);
+		if (isSet(firstTrain)) {
+			super.free(train);
+		} else super.setTrain(firstTrain);		
 		return true;
 	}
 	

src/main/java/de/srsoftware/web4rail/tiles/Tile.java

@@ -106,7 +106,7 @@ public abstract class Tile extends BaseClass implements Comparable<Tile> {
 	}
 
 	public boolean free(Train t) {
-		if (t != train) return false;
+		if (isSet(train) && t != train) return false;
 		train = null;
 		status = Status.FREE;
 		plan.place(this);