Oups complete previous (early) commit.

Bug fixes:
- AbstractEngine, after a go wtime xxx that ends with an exception, a go
command (without time options) continues to use the previous max time.
- AbstractEngine hanged with no transposition table

README.md

@@ -31,7 +31,7 @@ It does not directly support the following commands (but you can add them in an
 - **Dont miss the ShredderChess Annual Barbeque**: This command was in the original specification ... But was a joke.
 - **register**: As a promoter of open source free sofware, I will not encourage you to develop software that requires registration.
 - **ponderhit** is not yet implemented.
-- Only depth, score, hashfull and pv are implemented in info lines preceeding go reply.
+- Only depth, score and pv are implemented in info lines preceding go reply.
 
 It also does not recognize commands starting with unknown token (to be honest, it's not very hard to implement but seemed a very bad, error prone, idea to me).
 
@@ -92,4 +92,5 @@ If you do not use the *com.fathzer.jchess.uci.extended* and *com.fathzer.jchess.
 
 ## TODO
 * Verify the engine is protected against strange client behavior (like changing the position during a go request).
+* Implement support for multi-PV search.
 * Implement support for pondering.

pom.xml

@@ -22,7 +22,7 @@
 		<dependency>
 			<groupId>com.fathzer</groupId>
 			<artifactId>games-core</artifactId>
-			<version>0.0.11-SNAPSHOT</version>
+			<version>0.0.12-SNAPSHOT</version>
 		</dependency>
 		<dependency>
 			<groupId>org.junit.jupiter</groupId>
@@ -36,6 +36,11 @@
 			<version>4.2.2</version>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.mockito</groupId>
+			<artifactId>mockito-junit-jupiter</artifactId>
+			<version>5.14.2</version>
+		</dependency>
 	</dependencies>
 
 	<build>

src/main/java/com/fathzer/jchess/uci/BackgroundTaskManager.java

@@ -5,21 +5,23 @@
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Consumer;
 
+import com.fathzer.games.util.exec.CustomThreadFactory;
+import com.fathzer.jchess.uci.UCI.ThrowingRunnable;
+
 class BackgroundTaskManager implements AutoCloseable {
 	static class Task {
 		private final Consumer<Exception> logger;
-		private final Runnable run;
+		private final ThrowingRunnable run;
 		private final Runnable stopTask;
 
-		Task(Runnable task, Runnable stopTask, Consumer<Exception> logger) {
+		Task(ThrowingRunnable task, Runnable stopTask, Consumer<Exception> logger) {
 			this.run = task;
 			this.stopTask = stopTask;
 			this.logger = logger;
 		}
 	}
-
-
-	private final ExecutorService exec = Executors.newFixedThreadPool(1);
+
+	private final ExecutorService exec = Executors.newFixedThreadPool(1, new CustomThreadFactory(()->"Stoppable Tasks", true));
 	private final AtomicReference<Task> current = new AtomicReference<>();
 
 	boolean doBackground(Task task) {

src/main/java/com/fathzer/jchess/uci/Engine.java

@@ -105,7 +105,7 @@ default List<Option<?>> getOptions() {
 	 * <li>The supplier should be cooperative with the stopper; It should end as quickly as possible when stopper is invoked and <b>always</b> return a move.</li>
 	 * </ul>
 	 * @param params The go parameters.
-	 * @return A long running task able to compute the engine's move.
+	 * @return A task able to compute the engine's move.
 	 */
-	LongRunningTask<GoReply> go(GoParameters params);
+	StoppableTask<GoReply> go(GoParameters params);
 }

src/main/java/com/fathzer/jchess/uci/StoppableTask.java

@@ -1,24 +1,15 @@
 package com.fathzer.jchess.uci;
 
-import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.Callable;
 
-/** A task that will be executed in the background of UCI interface.
+/** A task that can be stopped.
+ * <br>Please note that stoppable is different from {@link java.util.concurrent.Cancellable}
+ * When a task is cancelled, it produces no result (for example, a {@link java.util.concurrent.CancellationException} if the task was cancelled).
+ * The typical use case of a StoppableTask is a best move search engine that performs iterative deepening. You may want to stop its deepening and get the current result.  
  * @param <T> The result of the task
  */
-public abstract class LongRunningTask<T> {
-	private final AtomicBoolean stopped;
-
-	protected LongRunningTask() {
-		stopped = new AtomicBoolean();
-	}
-
-	public abstract T get();
-
-	public boolean isStopped() {
-		return stopped.get();
-	}
-
-	public void stop() {
-		stopped.set(true);
-	}
+public interface StoppableTask<T> extends Callable<T> {
+	/** Stops the task.
+	 */
+	void stop();
 }

src/main/java/com/fathzer/jchess/uci/UCI.java

@@ -37,7 +37,14 @@
  */
 public class UCI implements Runnable, AutoCloseable {
 	public static final String INIT_COMMANDS_PROPERTY_FILE = "uciInitCommands";
-
+
+	@FunctionalInterface
+	/** A runnable that can throw an exception.
+	 */
+	public interface ThrowingRunnable {
+		void run() throws Exception;
+	}
+
 	private static final BufferedReader IN = new BufferedReader(new InputStreamReader(System.in));
 	private static final String MOVES = "moves";
 	private static final String ENGINE_CMD = "engine";
@@ -196,7 +203,7 @@ private String getFEN(Collection<String> tokens) {
 	 * @param logger Where to send the exceptions 
 	 * @return true if the task is launched, false if another task is already running.
 	 */
-	protected boolean doBackground(Runnable task, Runnable stopper, Consumer<Exception> logger) {
+	protected boolean doBackground(ThrowingRunnable task, Runnable stopper, Consumer<Exception> logger) {
 		return backTasks.doBackground(new Task(task, stopper, logger));
 	}
 
@@ -206,9 +213,9 @@ protected void doGo(Deque<String> tokens) {
 		} else {
 			final Optional<GoParameters> goOptions = parse(GoParameters::new, GoParameters.PARSER, tokens);
 			if (goOptions.isPresent()) {
-				final LongRunningTask<GoReply> task = engine.go(goOptions.get());
+				final StoppableTask<GoReply> task = engine.go(goOptions.get());
 				final boolean started = doBackground(() -> {
-					final GoReply goReply = task.get();
+					final GoReply goReply = task.call();
 					final Optional<String> mainInfo = goReply.getMainInfoString();
 					if (mainInfo.isPresent()) {
 						this.out(mainInfo.get());

src/main/java/com/fathzer/jchess/uci/extended/ExtendedUCI.java

@@ -15,7 +15,7 @@
 import com.fathzer.games.perft.PerfTTestData;
 import com.fathzer.games.perft.TestableMoveGeneratorBuilder;
 import com.fathzer.jchess.uci.Engine;
-import com.fathzer.jchess.uci.LongRunningTask;
+import com.fathzer.jchess.uci.StoppableTask;
 import com.fathzer.jchess.uci.UCI;
 import com.fathzer.jchess.uci.parameters.PerfStatsParameters;
 import com.fathzer.jchess.uci.parameters.PerfTParameters;
@@ -67,22 +67,16 @@ protected <M> void doPerft(Deque<String> tokens) {
 		final Optional<PerfTParameters> params = parse(PerfTParameters::new, PerfTParameters.PARSER, tokens);
 		if (params.isPresent()) {
 			@SuppressWarnings("unchecked")
-			final LongRunningTask<PerfTResult<M>> task = new PerftTask<>((MoveGeneratorSupplier<M>)engine, params.get());
+			final StoppableTask<PerfTResult<M>> task = new PerftTask<>((MoveGeneratorSupplier<M>)engine, params.get());
 			if (!doBackground(() -> doPerft(task, params.get()), task::stop, e -> err(PERFT_COMMAND,e))) {
 				debug("Engine is already working");
 			}
 		}
 	}
-
-//	private void background(Runnable task, Runnable stopper) {
-//		if (!doBackground(task, stopper, e -> out(e,0))) {
-//			debug("Engine is already working");
-//		}
-//	}
 
-	private <M> void doPerft(LongRunningTask<PerfTResult<M>> task, PerfTParameters params) {
+	private <M> void doPerft(StoppableTask<PerfTResult<M>> task, PerfTParameters params) throws Exception {
 		final long start = System.currentTimeMillis(); 
-		final PerfTResult<M> result = task.get();
+		final PerfTResult<M> result = task.call();
 
 		final long duration = System.currentTimeMillis() - start;
 		if (result.isInterrupted()) {

src/main/java/com/fathzer/jchess/uci/extended/PerftTask.java

@@ -6,10 +6,10 @@
 import com.fathzer.games.perft.PerfT;
 import com.fathzer.games.perft.PerfTResult;
 import com.fathzer.games.util.exec.ContextualizedExecutor;
-import com.fathzer.jchess.uci.LongRunningTask;
+import com.fathzer.jchess.uci.StoppableTask;
 import com.fathzer.jchess.uci.parameters.PerfTParameters;
 
-class PerftTask<M> extends LongRunningTask<PerfTResult<M>> {
+class PerftTask<M> implements StoppableTask<PerfTResult<M>> {
 	private PerfT<M> perft;
 	private final Supplier<MoveGenerator<M>> engine;
 	private final PerfTParameters params;
@@ -21,7 +21,7 @@ public PerftTask(Supplier<MoveGenerator<M>> engine, PerfTParameters params) {
 	}
 
 	@Override
-	public PerfTResult<M> get() {
+	public PerfTResult<M> call() {
 		try (ContextualizedExecutor<MoveGenerator<M>> exec = new ContextualizedExecutor<>(params.getParallelism())) {
 			this.perft = new PerfT<>(exec);
 			if (params.isLegal()) {
@@ -36,7 +36,6 @@ public PerfTResult<M> get() {
 
 	@Override
 	public void stop() {
-		super.stop();
 		perft.interrupt();
 	}
 

src/main/java/com/fathzer/jchess/uci/helper/AbstractEngine.java

@@ -23,9 +23,9 @@
 import com.fathzer.jchess.uci.GoReply.Info;
 import com.fathzer.jchess.uci.GoReply.MateScore;
 import com.fathzer.jchess.uci.GoReply.Score;
+import com.fathzer.jchess.uci.StoppableTask;
 import com.fathzer.jchess.uci.ClassicalOptions;
 import com.fathzer.jchess.uci.Engine;
-import com.fathzer.jchess.uci.LongRunningTask;
 import com.fathzer.jchess.uci.UCIMove;
 import com.fathzer.jchess.uci.extended.MoveGeneratorSupplier;
 import com.fathzer.jchess.uci.extended.MoveToUCIConverter;
@@ -64,7 +64,8 @@ public abstract class AbstractEngine<M, B extends MoveGenerator<M>> implements E
 	 */
 	protected AbstractEngine(IterativeDeepeningEngine<M, B> engine, TimeManager<B> timeManager) {
 		this.engine = engine;
-		this.ttSizeInMB = engine.getTranspositionTable().getMemorySizeMB();
+		final TranspositionTable<M> transpositionTable = engine.getTranspositionTable();
+		this.ttSizeInMB = transpositionTable==null ? -1 : transpositionTable.getMemorySizeMB();
 		this.defaultThreads = engine.getParallelism();
 		this.defaultDepth = engine.getDeepeningPolicy().getDepth();
 		this.defaultMaxTime = engine.getDeepeningPolicy().getMaxTime();
@@ -85,8 +86,10 @@ public int getDefaultHashTableSize() {
 
 	@Override
 	public void setHashTableSize(int sizeInMB) {
-		if (engine.getTranspositionTable().getMemorySizeMB()!=sizeInMB) {
-			engine.setTranspositionTable(buildTranspositionTable(sizeInMB));
+		final TranspositionTable<M> transpositionTable = engine.getTranspositionTable();
+		final int currentSize = transpositionTable==null ? -1 : transpositionTable.getMemorySizeMB();
+		if (currentSize!=sizeInMB) {
+			engine.setTranspositionTable(sizeInMB<0 ? null : buildTranspositionTable(sizeInMB));
 		}
 	}
 
@@ -130,41 +133,43 @@ public void move(UCIMove move) {
 	}
 
 	@Override
-	public LongRunningTask<GoReply> go(GoParameters options) {
-		return new LongRunningTask<>() {
+	public StoppableTask<GoReply> go(GoParameters options) {
+		return new StoppableTask<>() {
 			@Override
-			public GoReply get() {
+			public GoReply call() {
 				final UCIEngineSearchConfiguration<M, B> c = new UCIEngineSearchConfiguration<>(timeManager);
 				final UCIEngineSearchConfiguration.EngineConfiguration previous = c.configure(engine, options, board);
-				final List<M> candidates = options.getMoveToSearch().stream().map(AbstractEngine.this::toMove).toList();
-				final SearchHistory<M> search = engine.getBestMoves(board, candidates.isEmpty() ? null : candidates);
-				c.set(engine, previous);
-				if (search.isEmpty()) {
-					return new GoReply(null);
+				try {
+					final List<M> candidates = options.getMoveToSearch().stream().map(AbstractEngine.this::toMove).toList();
+					final SearchHistory<M> search = engine.getBestMoves(board, candidates.isEmpty() ? null : candidates);
+					if (search.isEmpty()) {
+						return new GoReply(null);
+					}
+					final EvaluatedMove<M> move = getSelected(board, search);
+					final GoReply goReply = new GoReply(toUCI(move.getContent()));
+					final Info info = new Info(search.getDepth());
+					final TranspositionTable<M> tt = engine.getTranspositionTable();
+					final int entryCount = tt.getEntryCount();
+					if (entryCount>0) {
+						info.setHashFull((int)(1000L*entryCount/tt.getSize()));
+					}
+					final List<EvaluatedMove<M>> bestMoves = search.getBestMoves();
+					final Map<String, Optional<Score>> scores = bestMoves.stream().collect(Collectors.toMap(em -> toUCI(em.getContent()).toString(), em -> toScore(em.getEvaluation())));
+					info.setScoreBuilder(m -> scores.get(m.toString()));
+					info.setPvBuilder(m -> {
+						final List<UCIMove> list = tt.collectPV(board, toMove(m), info.getDepth()).stream().map(x -> toUCI(x)).toList();
+						return list.isEmpty() ? Optional.empty() : Optional.of(list);
+					});
+					info.setExtraMoves(bestMoves.stream().filter(em -> !move.getContent().equals(em.getContent())).limit(engine.getDeepeningPolicy().getSize()-1).map(em->toUCI(em.getContent())).toList());
+					goReply.setInfo(info);
+					return goReply;
+				} finally {
+					c.set(engine, previous);
 				}
-				final EvaluatedMove<M> move = getSelected(board, search);
-				final GoReply goReply = new GoReply(toUCI(move.getContent()));
-				final Info info = new Info(search.getDepth());
-				final TranspositionTable<M> tt = engine.getTranspositionTable();
-				final int entryCount = tt.getEntryCount();
-				if (entryCount>0) {
-					info.setHashFull((int)(1000L*entryCount/tt.getSize()));
-				}
-				final List<EvaluatedMove<M>> bestMoves = search.getBestMoves();
-				final Map<String, Optional<Score>> scores = bestMoves.stream().collect(Collectors.toMap(em -> toUCI(em.getContent()).toString(), em -> toScore(em.getEvaluation())));
-				info.setScoreBuilder(m -> scores.get(m.toString()));
-				info.setPvBuilder(m -> {
-					final List<UCIMove> list = tt.collectPV(board, toMove(m), info.getDepth()).stream().map(x -> toUCI(x)).toList();
-					return list.isEmpty() ? Optional.empty() : Optional.of(list);
-				});
-				info.setExtraMoves(bestMoves.stream().filter(em -> !move.getContent().equals(em.getContent())).limit(engine.getDeepeningPolicy().getSize()-1).map(em->toUCI(em.getContent())).toList());
-				goReply.setInfo(info);
-				return goReply;
 			}
 
 			@Override
 			public void stop() {
-				super.stop();
 				engine.interrupt();
 			}
 		};

src/test/java/com/fathzer/jchess/uci/UCITest.java

@@ -139,11 +139,15 @@ void bug20241123() {
 		engine.setPositionConsumer(s -> {});
 		assertTrue(uci.post("position fen toto", 10));
 
-		engine.setGoFunction(s -> new LongRunningTask<>() {
+		engine.setGoFunction(s -> new StoppableTask<>() {
 			@Override
-			public GoReply get() {
+			public GoReply call() {
 				throw new UnsupportedOperationException("I'm a buggy engine");
 			}
+
+			@Override
+			public void stop() {
+			}
 		});
 		uci.post("go", 10);
 		await().atMost(200, TimeUnit.MILLISECONDS).until(() -> uci.getExceptions().getOrDefault("go", new IllegalArgumentException()).getClass()==UnsupportedOperationException.class);