If available, pass the changed path to the watch's onChange listener

src/main/java/play/dev/filewatch/DefaultFileWatchService.java

@@ -9,6 +9,9 @@
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.FileSystems;
+import java.nio.file.Path;
+import java.util.Optional;
+import java.util.function.Consumer;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
@@ -37,7 +40,7 @@ public DefaultFileWatchService(LoggerProxy logger, boolean isMac) {
   }
 
   @Override
-  public FileWatcher watch(Iterable<File> filesToWatch, Runnable onChange) {
+  public FileWatcher watch(Iterable<File> filesToWatch, Consumer<Optional<Path>> onChange) {
     var dirsToWatch =
         StreamSupport.stream(filesToWatch.spliterator(), false)
             .filter(
@@ -65,7 +68,7 @@ public FileWatcher watch(Iterable<File> filesToWatch, Runnable onChange) {
       var directoryWatcher =
           DirectoryWatcher.builder()
               .paths(dirsToWatch.map(File::toPath).collect(Collectors.toList()))
-              .listener(__ -> onChange.run())
+              .listener(dirChangeEvent -> onChange.accept(Optional.of(dirChangeEvent.path())))
               .fileHashing(!disableFileHashCheck)
               .watchService(watchService)
               .build();

src/main/java/play/dev/filewatch/FileWatchService.java

@@ -5,8 +5,11 @@
 package play.dev.filewatch;
 
 import java.io.File;
+import java.nio.file.Path;
 import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.Callable;
+import java.util.function.Consumer;
 
 /** A service that can watch files */
 public interface FileWatchService {
@@ -18,16 +21,16 @@ public interface FileWatchService {
    * @param onChange A callback that is executed whenever something changes.
    * @return A watcher
    */
-  FileWatcher watch(Iterable<File> filesToWatch, Runnable onChange);
+  FileWatcher watch(Iterable<File> filesToWatch, Consumer<Optional<Path>> onChange);
 
   /**
-   * @deprecated Use {@link #watch(Iterable, Runnable)} instead
+   * @deprecated Use {@link #watch(Iterable, Consumer)} instead
    */
   @Deprecated(since = "3.0.0", forRemoval = true)
   default FileWatcher watch(List<File> filesToWatch, Callable<Void> onChange) {
     return watch(
         filesToWatch,
-        () -> {
+        dirChangeEvent -> {
           try {
             onChange.call();
           } catch (RuntimeException e) {
@@ -112,7 +115,7 @@ static FileWatchService detect(
     return new FileWatchService() {
 
       @Override
-      public FileWatcher watch(Iterable<File> filesToWatch, Runnable onChange) {
+      public FileWatcher watch(Iterable<File> filesToWatch, Consumer<Optional<Path>> onChange) {
         return delegate.watch(filesToWatch, onChange);
       }
 

src/main/java/play/dev/filewatch/PollingFileWatchService.java

@@ -8,6 +8,8 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.Optional;
+import java.util.function.Consumer;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
@@ -36,7 +38,7 @@ private static Iterable<File> listRecursively(Iterable<File> files) {
   }
 
   @Override
-  public FileWatcher watch(Iterable<File> filesToWatch, Runnable onChange) {
+  public FileWatcher watch(Iterable<File> filesToWatch, Consumer<Optional<Path>> onChange) {
     stopped = false;
 
     var thread =
@@ -51,7 +53,7 @@ public FileWatcher watch(Iterable<File> filesToWatch, Runnable onChange) {
                         state,
                         () -> stopped);
                 if (result.isTriggered()) {
-                  onChange.run();
+                  onChange.accept(Optional.empty());
                 }
                 state = result.getState();
               }

src/test/scala/play/dev/filewatch/FileWatchServiceSpec.scala

@@ -100,7 +100,7 @@ abstract class FileWatchServiceSpec extends Specification {
   }
 
   private def watchFiles[T](files: File*)(block: => T): T = {
-    val watcher = watchService.watch(files.map(_.toJava).asJava, () => reportChange())
+    val watcher = watchService.watch(files.map(_.toJava).asJava, maybePath => reportChange())
     reset()
     try {
       block