Improved watch goal

Author: adrienlauer

src/license/THIRD-PARTY.properties

@@ -13,7 +13,7 @@
 # Please fill the missing licenses for dependencies :
 #
 #
-#Mon Nov 20 23:13:24 CET 2017
+#Tue Nov 21 14:05:44 CET 2017
 classworlds--classworlds--1.1-alpha-2=
 commons-collections--commons-collections--3.1=
 dom4j--dom4j--1.6.1=

src/main/java/org/seedstack/maven/WatchMojo.java

@@ -40,7 +40,7 @@
 import org.objectweb.asm.ClassVisitor;
 import org.objectweb.asm.FieldVisitor;
 import org.objectweb.asm.MethodVisitor;
-import org.seedstack.maven.classloader.HotSwapURLClassLoader;
+import org.seedstack.maven.classloader.ReloadingClassLoader;
 import org.seedstack.maven.runnables.DefaultLauncherRunnable;
 import org.seedstack.maven.watcher.AggregatingFileChangeListener;
 import org.seedstack.maven.watcher.DirectoryWatcher;
@@ -57,7 +57,7 @@ public class WatchMojo extends AbstractExecutableMojo {
     private Thread watcherThread;
     private AggregatingFileChangeListener fileChangeListener;
     private List<String> compileSourceRoots;
-    private HotSwapURLClassLoader hotSwapURLClassLoader;
+    private ReloadingClassLoader reloadingClassLoader;
     private DefaultLauncherRunnable launcherRunnable;
 
     @Override
@@ -106,26 +106,37 @@ public void run() {
 
     @Override
     URLClassLoader getClassLoader(final URL[] classPathUrls) {
-        hotSwapURLClassLoader = AccessController.doPrivileged(new PrivilegedAction<HotSwapURLClassLoader>() {
-            public HotSwapURLClassLoader run() {
-                return new HotSwapURLClassLoader(getLog(), classPathUrls);
+        reloadingClassLoader = AccessController.doPrivileged(new PrivilegedAction<ReloadingClassLoader>() {
+            public ReloadingClassLoader run() {
+                return new ReloadingClassLoader(getLog(), classPathUrls);
             }
         });
-        return hotSwapURLClassLoader;
+        return reloadingClassLoader;
     }
 
     private class WatchFileChangeListener extends AggregatingFileChangeListener {
         @Override
         public void onAggregatedChanges(Set<FileEvent> fileEvents) {
-
             try {
+                if (getLog().isDebugEnabled()) {
+                    for (FileEvent fileEvent : fileEvents) {
+                        getLog().debug(fileEvent.getKind().name() + ": " + fileEvent.getFile().getAbsolutePath());
+                    }
+                }
+
                 Set<File> compiledFilesToRemove = new HashSet<>();
                 Set<File> compiledFilesToUpdate = new HashSet<>();
+
                 analyzeEvents(fileEvents, compiledFilesToRemove, compiledFilesToUpdate);
-                hotSwapURLClassLoader.invalidateClasses(analyzeClasses(compiledFilesToRemove, compiledFilesToUpdate));
-                removeFiles(compiledFilesToRemove);
-                recompile();
-                launcherRunnable.refresh();
+
+                if (!compiledFilesToRemove.isEmpty() || !compiledFilesToUpdate.isEmpty()) {
+                    reloadingClassLoader.invalidateClasses(
+                            analyzeClasses(compiledFilesToRemove, compiledFilesToUpdate)
+                    );
+                    removeFiles(compiledFilesToRemove);
+                    recompile();
+                    launcherRunnable.refresh();
+                }
             } catch (Exception e) {
                 Throwable toLog = e.getCause();
                 if (toLog == null || !toLog.getClass().getName()

src/main/java/org/seedstack/maven/classloader/DisposableClassLoader.java

@@ -5,17 +5,20 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
-
 package org.seedstack.maven.classloader;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
 import java.io.IOException;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.nio.ByteBuffer;
 import java.security.AccessControlContext;
 import java.security.AccessController;
+import java.security.CodeSigner;
+import java.security.CodeSource;
 import java.security.PrivilegedExceptionAction;
+import java.security.SecureClassLoader;
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.HashMap;
@@ -26,15 +29,15 @@
 import sun.misc.Resource;
 import sun.misc.URLClassPath;
 
-public class HotSwapURLClassLoader extends URLClassLoader {
+public class ReloadingClassLoader extends URLClassLoader {
     private final AccessControlContext acc = AccessController.getContext();
     private final URLClassPath ucp;
     private final ObjectMapper objectMapper;
     private final Set<String> packagesToScan;
     private final Map<String, DisposableClassLoader> classLoaders = new HashMap<>();
     private final Log log;
 
-    public HotSwapURLClassLoader(Log log, URL[] urls) {
+    public ReloadingClassLoader(Log log, URL[] urls) {
         super(urls);
         this.log = log;
         this.ucp = new URLClassPath(urls);
@@ -77,7 +80,7 @@ public DisposableClassLoader run() throws ClassNotFoundException {
                             String path = name.replace('.', '/').concat(".class");
                             Resource res = ucp.getResource(path, false);
                             if (res != null) {
-                                return new DisposableClassLoader(HotSwapURLClassLoader.this, name, res);
+                                return new DisposableClassLoader(name, res);
                             } else {
                                 return null;
                             }
@@ -127,4 +130,49 @@ private Set<String> resolvePackagesToScan(URL url) {
                     "Unable to retrieve content of application configuration file: " + url.toExternalForm(), e);
         }
     }
+
+    private class DisposableClassLoader extends SecureClassLoader {
+        private final Resource res;
+        private final String name;
+
+        DisposableClassLoader(String name, Resource res) {
+            this.name = name;
+            this.res = res;
+        }
+
+        @Override
+        public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
+            if (this.name.equals(name)) {
+                synchronized (getClassLoadingLock(name)) {
+                    // First, check if the class has already been loaded
+                    Class<?> c = findLoadedClass(name);
+                    if (c == null) {
+                        try {
+                            ByteBuffer byteBuffer = res.getByteBuffer();
+                            if (byteBuffer != null) {
+                                // Use (direct) ByteBuffer:
+                                CodeSigner[] signers = res.getCodeSigners();
+                                CodeSource cs = new CodeSource(res.getURL(), signers);
+                                c = defineClass(name, byteBuffer, cs);
+                            } else {
+                                byte[] b = res.getBytes();
+                                // must read certificates AFTER reading bytes.
+                                CodeSigner[] signers = res.getCodeSigners();
+                                CodeSource cs = new CodeSource(res.getURL(), signers);
+                                c = defineClass(name, b, 0, b.length, cs);
+                            }
+                        } catch (IOException e) {
+                            throw new ClassNotFoundException(name, e);
+                        }
+                        if (resolve) {
+                            resolveClass(c);
+                        }
+                    }
+                    return c;
+                }
+            } else {
+                return ReloadingClassLoader.this.loadClass(name, resolve);
+            }
+        }
+    }
 }

…n/classloader/HotSwapURLClassLoader.java …en/classloader/ReloadingClassLoader.javasrc/main/java/org/seedstack/maven/classloader/HotSwapURLClassLoader.java renamed to src/main/java/org/seedstack/maven/classloader/ReloadingClassLoader.java src/main/java/org/seedstack/maven/classloader/HotSwapURLClassLoader.java renamed to src/main/java/org/seedstack/maven/classloader/ReloadingClassLoader.java

@@ -16,26 +16,27 @@
 
 public abstract class AggregatingFileChangeListener implements FileChangeListener {
     private final ArrayBlockingQueue<FileEvent> pending = new ArrayBlockingQueue<>(10000);
-    private final Timer timer = new Timer();
+    private Timer timer;
     private boolean stop;
 
-    protected AggregatingFileChangeListener() {
-        this.timer.scheduleAtFixedRate(new TimerTask() {
-            @Override
-            public void run() {
-                Set<FileEvent> aggregatedChangedFiles = new HashSet<>();
-                pending.drainTo(aggregatedChangedFiles);
-                if (!aggregatedChangedFiles.isEmpty()) {
-                    onAggregatedChanges(aggregatedChangedFiles);
-                }
-            }
-        }, 0, 250);
-    }
-
     @Override
-    public void onChange(Set<FileEvent> fileEvents) {
+    public void onChange(final Set<FileEvent> fileEvents) {
         if (!stop) {
+            if (this.timer != null) {
+                this.timer.cancel();
+            }
+
             pending.addAll(fileEvents);
+
+            this.timer = new Timer();
+            this.timer.schedule(new TimerTask() {
+                @Override
+                public void run() {
+                    HashSet<FileEvent> aggregatedFileEvents = new HashSet<>();
+                    pending.drainTo(aggregatedFileEvents);
+                    onAggregatedChanges(aggregatedFileEvents);
+                }
+            }, 500);
         }
     }