ReadOnlyState: Use NIO file API

Change-Id: I19e4efabcf2f435a178a165ae865b239f68d4930

src/main/java/com/googlesource/gerrit/plugins/readonly/ReadOnlyState.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/readonly/ReadOnlyState.java b/src/main/java/com/googlesource/gerrit/plugins/readonly/ReadOnlyState.java
index 05c7a91..b6c4def 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/readonly/ReadOnlyState.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/readonly/ReadOnlyState.java
@@ -17,31 +17,31 @@
 import com.google.gerrit.server.config.SitePaths;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
-import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 
 @Singleton
 public class ReadOnlyState {
   private static final String GERRIT_READONLY = "gerrit.readonly";
 
-  private final File marker;
+  private final Path marker;
 
   @Inject
   ReadOnlyState(SitePaths sitePaths) {
-    this.marker = sitePaths.etc_dir.resolve(GERRIT_READONLY).toFile();
+    this.marker = sitePaths.etc_dir.resolve(GERRIT_READONLY);
   }
 
   public boolean isReadOnly() {
-    return marker.exists();
+    return Files.exists(marker);
   }
 
   public void setReadOnly(boolean readOnly) throws IOException {
-    if (readOnly && !marker.exists()) {
-      Files.newOutputStream(marker.toPath(), StandardOpenOption.CREATE).close();
-    } else if (!readOnly && marker.exists()) {
-      Files.delete(marker.toPath());
+    if (readOnly && !Files.exists(marker)) {
+      Files.newOutputStream(marker, StandardOpenOption.CREATE).close();
+    } else if (!readOnly && Files.exists(marker)) {
+      Files.delete(marker);
     }
   }
 }