Convert FileWatchListener to an interface

Original commit: elastic/x-pack-elasticsearch@da9f6eddc1

elasticsearch/license/base/src/main/java/org/elasticsearch/license/core/OperationModeFileWatcher.java

@@ -26,7 +26,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
  * In case of failure to read a valid operation mode from <code>licenseModePath</code>,
  * the operation mode will default to PLATINUM
  */
-public final class OperationModeFileWatcher extends FileChangesListener {
+public final class OperationModeFileWatcher implements FileChangesListener {
     private final ResourceWatcherService resourceWatcherService;
     private final Path licenseModePath;
     private final AtomicBoolean initialized = new AtomicBoolean();

elasticsearch/x-pack/security/src/main/java/org/elasticsearch/xpack/security/authc/file/FileUserPasswdStore.java

@@ -185,7 +185,7 @@ public class FileUserPasswdStore {
         }
     }
 
-    private class FileListener extends FileChangesListener {
+    private class FileListener implements FileChangesListener {
         @Override
         public void onFileCreated(Path file) {
             onFileChanged(file);

elasticsearch/x-pack/security/src/main/java/org/elasticsearch/xpack/security/authc/file/FileUserRolesStore.java

@@ -217,7 +217,7 @@ public class FileUserRolesStore {
         }
     }
 
-    private class FileListener extends FileChangesListener {
+    private class FileListener implements FileChangesListener {
         @Override
         public void onFileCreated(Path file) {
             onFileChanged(file);

elasticsearch/x-pack/security/src/main/java/org/elasticsearch/xpack/security/authc/support/DnRoleMapper.java

@@ -184,7 +184,7 @@ public class DnRoleMapper {
         }
     }
 
-    private class FileListener extends FileChangesListener {
+    private class FileListener implements FileChangesListener {
         @Override
         public void onFileCreated(Path file) {
             onFileChanged(file);

elasticsearch/x-pack/security/src/main/java/org/elasticsearch/xpack/security/authz/store/FileRolesStore.java

@@ -287,7 +287,7 @@ public class FileRolesStore extends AbstractLifecycleComponent implements RolesS
         return segments;
     }
 
-    private class FileListener extends FileChangesListener {
+    private class FileListener implements FileChangesListener {
 
         @Override
         public void onFileCreated(Path file) {

elasticsearch/x-pack/security/src/main/java/org/elasticsearch/xpack/security/ssl/TrustConfig.java

@@ -264,7 +264,7 @@ abstract class TrustConfig {
         }
     }
 
-    protected static class ChangeListener extends FileChangesListener {
+    protected static class ChangeListener implements FileChangesListener {
 
         private final List<Path> paths;
         private final Reloadable reloadable;