Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/6283#discussion_r202071547
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/executiongraph/restart/RestartStrategyResolving.java
---
@@ -0,0 +1,74 @@
+/*
+ * 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.executiongraph.restart;
+
+import org.apache.flink.api.common.restartstrategy.RestartStrategies;
+
+import javax.annotation.Nullable;
+
+/**
+ * Utility method for resolving {@link RestartStrategy}.
+ */
+public final class RestartStrategyResolving {
+
+ private static final long DEFAULT_RESTART_DELAY = 0;
+
+ /**
+ * Resolves which {@link RestartStrategy} to use. It should be used
only on the server side.
+ * The resolving strategy is as follows:
+ * <ol>
+ * <li>Strategy set within job graph.</li>
+ * <li>Strategy set flink-conf.yaml on the server set, unless is set to
{@link NoRestartStrategy} and checkpointing is enabled.</li>
+ * <li>If no strategy was set on client and server side and
checkpointing was enabled then {@link FixedDelayRestartStrategy} is used</li>
+ * </ol>
+ *
+ * @param clientConfiguration restart configuration given within the
job graph
+ * @param serverStrategyFactory default server side strategy factory
+ * @param isCheckpointingEnabled if checkpointing was enabled for the
job
+ * @return resolved strategy
+ */
+ public static RestartStrategy resolve(
+ @Nullable
RestartStrategies.RestartStrategyConfiguration clientConfiguration,
--- End diff --
By setting the default restart strategy to
`FallbackRestartStrategyConfiguration` in the `ExecutionConfig` we could remove
the `@Nullable` annotation here and simplify the code by avoiding the null
checks.
---
