Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/4898#discussion_r148802300
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/rest/messages/JobAccumulatorsInfo.java
---
@@ -0,0 +1,128 @@
+/*
+ * 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.rest.messages;
+
+import org.apache.flink.runtime.rest.handler.job.JobAccumulatorsHandler;
+import org.apache.flink.util.Preconditions;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+import javax.annotation.Nullable;
+
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Response type of the {@link JobAccumulatorsHandler}.
+ */
+public class JobAccumulatorsInfo implements ResponseBody {
+ public static final String FIELD_NAME_JOB_ACCUMULATORS =
"job-accumulators";
+ public static final String FIELD_NAME_USER_TASK_ACCUMULATORS =
"user-task-accumulators";
+
+ @JsonProperty(FIELD_NAME_JOB_ACCUMULATORS)
+ private List<JobAccumulator> jobAccumulators;
+
+ @JsonProperty(FIELD_NAME_USER_TASK_ACCUMULATORS)
+ private List<UserTaskAccumulator> userAccumulators;
+
+ @JsonCreator
+ public JobAccumulatorsInfo(
+ @JsonProperty(FIELD_NAME_JOB_ACCUMULATORS) @Nullable
List<JobAccumulator> jobAccumulators,
--- End diff --
I would remove the `Nullable` and instead pass in an
`Collections.emptyList()` if there are no job accumulators at the moment.
---
