Merge pull request #6 from mnlipp/fix/vthreads-conf

Allow usage of virtual threads to be disabled.
mnlipp · Oct 2, 2024 · 4921109 · 4921109
2 parents 92348d1 + 67724d1
commit 4921109
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Showing 8 changed files with 91 additions and 49 deletions.
diff --git a/org.jgrapes.core/src/org/jgrapes/core/Components.java b/org.jgrapes.core/src/org/jgrapes/core/Components.java
@@ -34,6 +34,7 @@
 import java.util.WeakHashMap;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.logging.Level;
 import org.jgrapes.core.annotation.ComponentManager;
@@ -53,11 +54,37 @@
 public class Components {
 
     private static ExecutorService defaultExecutorService
-        = Executors.newVirtualThreadPerTaskExecutor();
+        = useVirtualThreads() ? Executors.newVirtualThreadPerTaskExecutor()
+            : Executors.newCachedThreadPool(
+                new ThreadFactory() {
+                    @SuppressWarnings({ "PMD.CommentRequired",
+                        "PMD.MissingOverride" })
+                    public Thread newThread(Runnable runnable) {
+                        Thread thread
+                            = Executors.defaultThreadFactory()
+                                .newThread(runnable);
+                        thread.setDaemon(true);
+                        return thread;
+                    }
+                });
 
     private static ExecutorService timerExecutorService
         = defaultExecutorService;
 
+    /**
+     * JGrapes uses virtual thread by default. However, as of
+     * 2024, some debuggers still have problems with virtual
+     * threads. Therefore it is possible to switch back to
+     * platform threads by starting the JVM with property
+     * `-Djgrapes.useVirtualThreads=false`.
+     *
+     * @return true, if successful
+     */
+    public static boolean useVirtualThreads() {
+        return Boolean.parseBoolean(
+            System.getProperty("jgrapes.useVirtualThreads", "true"));
+    }
+
     private Components() {
     }
 
@@ -452,7 +479,8 @@ private static class Scheduler extends Thread {
          */
         @SuppressWarnings("PMD.ConstructorCallsOverridableMethod")
         public Scheduler() {
-            ofVirtual().name("Components.Scheduler").start(this);
+            (useVirtualThreads() ? ofVirtual() : ofPlatform())
+                .name("Components.Scheduler").start(this);
         }
 
         /**

diff --git a/org.jgrapes.io/src/org/jgrapes/io/InputStreamMonitor.java b/org.jgrapes.io/src/org/jgrapes/io/InputStreamMonitor.java
@@ -144,8 +144,9 @@ public void onStart(Start event) {
                 () -> {
                     return ByteBuffer.allocateDirect(bufferSize);
                 }, 2);
-            runner = Thread.ofVirtual().name(Components.simpleObjectName(this))
-                .start(this);
+            runner = (Components.useVirtualThreads() ? Thread.ofVirtual()
+                : Thread.ofPlatform()).name(Components.simpleObjectName(this))
+                    .start(this);
         }
     }
 

diff --git a/org.jgrapes.io/src/org/jgrapes/io/NioDispatcher.java b/org.jgrapes.io/src/org/jgrapes/io/NioDispatcher.java
@@ -63,8 +63,9 @@ public void onStart(Start event) {
             if (runner != null && !runner.isInterrupted()) {
                 return;
             }
-            runner = Thread.ofVirtual().name(Components.simpleObjectName(this))
-                .start(this);
+            runner = (Components.useVirtualThreads() ? Thread.ofVirtual()
+                : Thread.ofPlatform()).name(Components.simpleObjectName(this))
+                    .start(this);
         }
     }
 

diff --git a/org.jgrapes.io/src/org/jgrapes/io/util/ManagedBufferStreamer.java b/org.jgrapes.io/src/org/jgrapes/io/util/ManagedBufferStreamer.java
@@ -23,6 +23,8 @@
 import java.nio.Buffer;
 import java.nio.charset.Charset;
 import java.util.function.Consumer;
+
+import org.jgrapes.core.Components;
 import org.jgrapes.io.events.Input;
 
 /**
@@ -42,9 +44,10 @@ public class ManagedBufferStreamer implements InputConsumer {
      * @param processor the processor
      */
     public ManagedBufferStreamer(Consumer<Reader> processor) {
-        Thread thread = Thread.ofVirtual().start(() -> {
-            processor.accept(reader);
-        });
+        Thread thread = (Components.useVirtualThreads() ? Thread.ofVirtual()
+            : Thread.ofPlatform()).start(() -> {
+                processor.accept(reader);
+            });
         ThreadCleaner.watch(this, thread);
     }
 

diff --git a/org.jgrapes.io/src/org/jgrapes/io/util/ThreadCleaner.java b/org.jgrapes.io/src/org/jgrapes/io/util/ThreadCleaner.java
@@ -23,6 +23,8 @@
 import java.util.HashSet;
 import java.util.Set;
 
+import org.jgrapes.core.Components;
+
 /**
  * Cleans up threads if some object has been garbage collected.
  * 
@@ -71,18 +73,19 @@ public RefWithThread(Object referent, Thread thread) {
     }
 
     static {
-        Thread.ofVirtual().name("ThreadCleaner").start(() -> {
-            while (true) {
-                try {
-                    ThreadCleaner.RefWithThread ref
-                        = (ThreadCleaner.RefWithThread) abandoned.remove();
-                    ref.watched.interrupt();
-                    watched.remove(ref);
-                } catch (InterruptedException e) { // NOPMD
-                    // Nothing to do
+        (Components.useVirtualThreads() ? Thread.ofVirtual()
+            : Thread.ofPlatform()).name("ThreadCleaner").start(() -> {
+                while (true) {
+                    try {
+                        ThreadCleaner.RefWithThread ref
+                            = (ThreadCleaner.RefWithThread) abandoned.remove();
+                        ref.watched.interrupt();
+                        watched.remove(ref);
+                    } catch (InterruptedException e) { // NOPMD
+                        // Nothing to do
+                    }
                 }
-            }
-        });
+            });
     }
 
     /**

diff --git a/org.jgrapes.io/src/org/jgrapes/net/SocketServer.java b/org.jgrapes.io/src/org/jgrapes/net/SocketServer.java
@@ -417,7 +417,8 @@ public void onRegistered(NioRegistration.Completed event)
                 return;
             }
             registration = event.event().get();
-            purger = Thread.ofVirtual().start(new Purger());
+            purger = (Components.useVirtualThreads() ? Thread.ofVirtual()
+                : Thread.ofPlatform()).start(new Purger());
             fire(new Ready(serverSocketChannel.getLocalAddress()));
             return;
         }

diff --git a/org.jgrapes.util/src/org/jgrapes/util/FileSystemWatcher.java b/org.jgrapes.util/src/org/jgrapes/util/FileSystemWatcher.java
@@ -41,6 +41,7 @@
 import java.util.stream.StreamSupport;
 import org.jgrapes.core.Channel;
 import org.jgrapes.core.Component;
+import org.jgrapes.core.Components;
 import org.jgrapes.core.Event;
 import org.jgrapes.core.Manager;
 import org.jgrapes.core.annotation.Handler;
@@ -195,25 +196,26 @@ private Watcher(FileSystem fileSystem) throws IOException {
                 .stream(fileSystem.getRootDirectories().spliterator(), false)
                 .map(Path::toString)
                 .collect(Collectors.joining(File.pathSeparator));
-            Thread.ofVirtual().name(roots + " watcher")
-                .start(() -> {
-                    while (true) {
-                        try {
-                            WatchKey key = watchService.take();
-                            // Events have to be consumed
-                            key.pollEvents();
-                            if (!(key.watchable() instanceof Path)) {
+            (Components.useVirtualThreads() ? Thread.ofVirtual()
+                : Thread.ofPlatform()).name(roots + " watcher")
+                    .start(() -> {
+                        while (true) {
+                            try {
+                                WatchKey key = watchService.take();
+                                // Events have to be consumed
+                                key.pollEvents();
+                                if (!(key.watchable() instanceof Path)) {
+                                    key.reset();
+                                    continue;
+                                }
+                                handleWatchEvent((Path) key.watchable());
                                 key.reset();
-                                continue;
+                            } catch (InterruptedException e) {
+                                logger.log(Level.WARNING, e,
+                                    () -> "No WatchKey: " + e.getMessage());
                             }
-                            handleWatchEvent((Path) key.watchable());
-                            key.reset();
-                        } catch (InterruptedException e) {
-                            logger.log(Level.WARNING, e,
-                                () -> "No WatchKey: " + e.getMessage());
                         }
-                    }
-                });
+                    });
         }
     }
 

diff --git a/org.jgrapes.util/src/org/jgrapes/util/Password.java b/org.jgrapes.util/src/org/jgrapes/util/Password.java
@@ -24,6 +24,8 @@
 import java.util.Arrays;
 import java.util.Optional;
 
+import org.jgrapes.core.Components;
+
 /**
  * Stores a password in such a way that it can be cleared. Automatically 
  * clears the storage if an object of this type becomes weakly reachable.
@@ -50,19 +52,20 @@ public class Password {
     public Password(char[] password) {
         synchronized (Password.class) {
             if (purger == null) {
-                purger = Thread.ofVirtual().name("PasswordPurger").start(() -> {
-                    while (true) {
-                        try {
-                            Reference<? extends Password> passwordRef
-                                = toBeCleared.remove();
-                            Optional.ofNullable(passwordRef.get())
-                                .ifPresent(Password::clear);
-                            passwordRef.clear();
-                        } catch (InterruptedException e) {
-                            break;
+                purger = (Components.useVirtualThreads() ? Thread.ofVirtual()
+                    : Thread.ofPlatform()).name("PasswordPurger").start(() -> {
+                        while (true) {
+                            try {
+                                Reference<? extends Password> passwordRef
+                                    = toBeCleared.remove();
+                                Optional.ofNullable(passwordRef.get())
+                                    .ifPresent(Password::clear);
+                                passwordRef.clear();
+                            } catch (InterruptedException e) {
+                                break;
+                            }
                         }
-                    }
-                });
+                    });
             }
         }
         this.password = password;