Tweak thread names.

Especially the hook virtual threads, but also the mongo change receiver
thread and some test threads.

Author: prdoyle

bosk-core/src/main/java/works/bosk/Bosk.java

@@ -87,9 +87,13 @@ public class Bosk<R extends StateTreeNode> implements BoskInfo<R> {
 	private final ThreadLocal<R> rootSnapshot = new ThreadLocal<>();
 	private final HookRegistrar hookRegistrar;
 	private final Queue<HookRegistration<?>> hooks = new ConcurrentLinkedQueue<>();
-	private final ExecutorService hookExecutor = Executors.newVirtualThreadPerTaskExecutor();
 	private final PathCompiler pathCompiler;
 
+	private final Thread.Builder hookThreadBuilder = Thread
+		.ofVirtual()
+		.name("bosk-hook-", 1);
+	private final ExecutorService hookExecutor = Executors.newThreadPerTaskExecutor(hookThreadBuilder::unstarted);
+
 	// Mutable state
 	private volatile R currentRoot;
 

bosk-core/src/test/java/works/bosk/HooksTest.java

@@ -10,13 +10,15 @@
 import java.util.function.Consumer;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInfo;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.EnumSource;
 import org.junit.jupiter.params.provider.ValueSource;
 import works.bosk.annotations.Hook;
 import works.bosk.annotations.ReferencePath;
 import works.bosk.exceptions.InvalidTypeException;
 
+import static java.lang.Thread.currentThread;
 import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
@@ -64,6 +66,11 @@ void setupBosk() throws InvalidTypeException {
 		recorder = new HookRecorder();
 	}
 
+	@BeforeEach
+	void setThreadName(TestInfo testInfo) {
+		currentThread().setName("test: " + testInfo.getDisplayName());
+	}
+
 	@ParameterizedTest
 	@EnumSource(Variant.class)
 	void beforeRegistration_noHooks(Variant variant) {

bosk-mongo/src/main/java/works/bosk/drivers/mongo/internal/ChangeReceiver.java

@@ -55,7 +55,8 @@ class ChangeReceiver implements Closeable {
 	private final ChangeListener listener;
 	private final MongoDriverSettings settings;
 	private final MongoCollection<BsonDocument> collection;
-	private final ScheduledExecutorService ex = Executors.newScheduledThreadPool(1);
+	private final Thread.Builder threadBuilder = Thread.ofPlatform().name("bosk-mongo-change-receiver");
+	private final ScheduledExecutorService ex = Executors.newScheduledThreadPool(1, threadBuilder::unstarted);
 	private final Exception creationPoint;
 	private volatile @Nullable Thread thread = null;
 	private volatile boolean isClosed = false;
@@ -124,8 +125,6 @@ public void close() {
 	 * around the loop.
 	 */
 	private void connectionLoop() {
-		String oldThreadName = currentThread().getName();
-		currentThread().setName(getClass().getSimpleName() + " [" + boskName + "]");
 		try (MDCScope _ = setupMDC(boskName, boskID)) {
 			LOGGER.debug("Starting connectionLoop task");
 			try {
@@ -217,7 +216,6 @@ private void connectionLoop() {
 				}
 			} finally {
 				LOGGER.debug("Ending connectionLoop task; isClosed={}", isClosed);
-				currentThread().setName(oldThreadName);
 				thread = null;
 			}
 		} catch (RuntimeException e) {

bosk-testing/src/main/java/works/bosk/testing/drivers/AbstractDriverTest.java

@@ -36,15 +36,17 @@ public abstract class AbstractDriverTest {
 
 	@BeforeEach
 	void logStart(TestInfo testInfo) {
-		logTest("/=== Start", testInfo);
 		oldThreadName = Thread.currentThread().getName();
-		Thread.currentThread().setName(testInfo.getDisplayName());
+		String newThreadName = "test: " + testInfo.getDisplayName();
+		Thread.currentThread().setName(newThreadName);
+		logTest("/=== Start", testInfo);
+		LOGGER.debug("Old thread name was {}", oldThreadName);
 	}
 
 	@AfterEach
 	void logDone(TestInfo testInfo) {
-		Thread.currentThread().setName(oldThreadName);
 		logTest("\\=== Done", testInfo);
+		Thread.currentThread().setName(oldThreadName);
 	}
 
 	private static void logTest(String verb, TestInfo testInfo) {