Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/5239#discussion_r168473127
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/state/CheckpointStreamWithResultProvider.java
---
@@ -0,0 +1,175 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 org.apache.flink.runtime.state;
+
+import org.apache.flink.core.fs.Path;
+import
org.apache.flink.runtime.state.filesystem.FixFileFsStateOutputStream;
+import org.apache.flink.util.ExceptionUtils;
+import org.apache.flink.util.Preconditions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.Closeable;
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Interface that provides access to a CheckpointStateOutputStream and a
method to provide the {@link SnapshotResult}.
+ * This abstracts from different ways that a result is obtained from
checkpoint output streams.
+ */
+public interface CheckpointStreamWithResultProvider extends Closeable {
+
+ SnapshotResult<KeyedStateHandle> closeAndFinalizeCheckpointStreamResult(
+ KeyGroupRangeOffsets kgOffs) throws IOException;
+
+ CheckpointStreamFactory.CheckpointStateOutputStream
getCheckpointOutputStream();
+
+ @Override
+ default void close() throws IOException {
+ CheckpointStreamFactory.CheckpointStateOutputStream
outputStream = getCheckpointOutputStream();
+ if (outputStream != null) {
--- End diff --
Under which conditions is `outputStream` `null`? Maybe we could annotate
`getCheckpointOutputStream` with `Nullable`.
---
