Test & fix for FileWatcher

- Test for modification listening
- Fix for Path resolution when calling a WatchedFile

Plan/common/src/main/java/com/djrapitops/plan/utilities/file/FileWatcher.java

@@ -42,22 +42,25 @@ public class FileWatcher extends Thread {
     private Path watchedPath;
     private Set<WatchedFile> watchedFiles;
 
-    public FileWatcher(File folder, ErrorHandler errorHandler) {
-        this(folder, errorHandler, new HashSet<>());
+    public FileWatcher(
+            File folder,
+            ErrorHandler errorHandler
+    ) {
+        this(folder.toPath(), errorHandler);
     }
 
     public FileWatcher(
-            File folder,
-            ErrorHandler errorHandler,
-            Set<WatchedFile> watchedFiles
+            Path watchedPath,
+            ErrorHandler errorHandler
     ) {
         this.errorHandler = errorHandler;
         this.running = false;
-        this.watchedFiles = watchedFiles;
+        this.watchedFiles = new HashSet<>();
 
-        Verify.isTrue(folder.isDirectory(), () -> new IllegalArgumentException("Given File " + folder.getAbsolutePath() + " was not a folder."));
 
-        watchedPath = folder.toPath();
+        Verify.isTrue(watchedPath.toFile().isDirectory(), () -> new IllegalArgumentException("Given File " + watchedPath.toString() + " was not a folder."));
+
+        this.watchedPath = watchedPath;
     }
 
     public void addToWatchlist(WatchedFile watchedFile) {
@@ -73,6 +76,7 @@ public class FileWatcher extends Thread {
             runLoop(watcher);
         } catch (IOException e) {
             errorHandler.log(L.ERROR, this.getClass(), e);
+            interrupt();
         } catch (InterruptedException e) {
             interrupt();
         }
@@ -107,7 +111,7 @@ public class FileWatcher extends Thread {
         } else {
             @SuppressWarnings("unchecked")
             Path modifiedFile = ((WatchEvent<Path>) event).context();
-            actOnModification(modifiedFile);
+            actOnModification(watchedPath.resolve(modifiedFile));
         }
     }
 
@@ -122,4 +126,8 @@ public class FileWatcher extends Thread {
         running = false;
         super.interrupt();
     }
+
+    public boolean isRunning() {
+        return running;
+    }
 }

Plan/common/src/main/java/com/djrapitops/plan/utilities/file/WatchedFile.java

@@ -23,22 +23,26 @@ import java.nio.file.Path;
 import java.util.Objects;
 
 /**
- * File with a consumer that is called if the file is modified.
+ * File or Path with a function that is called if the file is modified.
  *
  * @author Rsl1122
  */
 public class WatchedFile {
 
-    private final File file;
+    private final Path watchedPath;
     private final VoidFunction onChange;
 
     public WatchedFile(File file, VoidFunction onChange) {
-        this.file = file;
+        this(file.toPath(), onChange);
+    }
+
+    public WatchedFile(Path path, VoidFunction onChange) {
+        this.watchedPath = path;
         this.onChange = onChange;
     }
 
     public void modified(Path modifiedPath) {
-        if (modifiedPath != null && file.toPath().equals(modifiedPath)) {
+        if (watchedPath.equals(modifiedPath)) {
             onChange.apply();
         }
     }
@@ -48,11 +52,11 @@ public class WatchedFile {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
         WatchedFile that = (WatchedFile) o;
-        return Objects.equals(file, that.file);
+        return Objects.equals(watchedPath, that.watchedPath);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(file);
+        return Objects.hash(watchedPath);
     }
 }

Plan/common/src/test/java/com/djrapitops/plan/utilities/file/FileWatcherTest.java

@@ -0,0 +1,62 @@
+package com.djrapitops.plan.utilities.file;
+
+import com.jayway.awaitility.Awaitility;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.platform.runner.JUnitPlatform;
+import org.junit.runner.RunWith;
+import org.junitpioneer.jupiter.TempDirectory;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Collections;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+@RunWith(JUnitPlatform.class)
+@ExtendWith(TempDirectory.class)
+class FileWatcherTest {
+
+    private Path temporaryDir;
+
+    @BeforeEach
+    void setUpTemporaryDir(@TempDirectory.TempDir Path dir) {
+        temporaryDir = dir;
+    }
+
+    @Test
+    void fileWatcherCallsWatchedFile() throws IOException {
+        FileWatcher underTest = new FileWatcher(temporaryDir, null);
+        File modified = temporaryDir.resolve("modifiedFile").toFile();
+
+        AtomicBoolean methodWasCalled = new AtomicBoolean(false);
+        WatchedFile watchedFile = new WatchedFile(modified, () -> methodWasCalled.set(true));
+        underTest.addToWatchlist(watchedFile);
+
+        try {
+            underTest.start();
+            Awaitility.await()
+                    .atMost(5, TimeUnit.SECONDS)
+                    .until(underTest::isRunning);
+
+            // Modification should trigger a watch event here.
+            createAndModifyFile(modified);
+
+            Awaitility.await()
+                    .atMost(1, TimeUnit.SECONDS)
+                    .until(methodWasCalled::get);
+        } finally {
+            underTest.interrupt();
+        }
+    }
+
+    private void createAndModifyFile(File modified) throws IOException {
+        modified.createNewFile();
+        Files.write(modified.toPath(), Collections.singletonList("DataToWrite"), StandardCharsets.UTF_8);
+        Files.write(modified.toPath(), Collections.singletonList("OverWrite"), StandardCharsets.UTF_8);
+    }
+}