1 files changed, 35 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/notedb/rebuild/NotesMigrationStateListener.java b/java/com/google/gerrit/server/notedb/rebuild/NotesMigrationStateListener.java
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index 0000000000..aef30a2a51
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+++ b/java/com/google/gerrit/server/notedb/rebuild/NotesMigrationStateListener.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.notedb.rebuild;
+
+import com.google.gerrit.extensions.annotations.ExtensionPoint;
+import com.google.gerrit.server.notedb.NotesMigrationState;
+import java.io.IOException;
+
+/** Listener for state changes performed by {@link OnlineNoteDbMigrator}. */
+@ExtensionPoint
+public interface NotesMigrationStateListener {
+  /**
+   * Invoked just before saving the new migration state.
+   *
+   * @param oldState state prior to this state change.
+   * @param newState state after this state change.
+   * @throws IOException if an error occurred, which will cause the migration to abort. Exceptions
+   *     that should be considered non-fatal must be caught (and ideally logged) by the
+   *     implementation rather than thrown.
+   */
+  void preStateChange(NotesMigrationState oldState, NotesMigrationState newState)
+      throws IOException;
+}