Github user HeartSaVioR commented on a diff in the pull request:
https://github.com/apache/metron/pull/1039#discussion_r192274429
--- Diff:
metron-platform/metron-storm-kafka-override/src/main/java/org/apache/storm/kafka/spout/KafkaSpoutRetryExponentialBackoff.java
---
@@ -0,0 +1,328 @@
+/*
+ * 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.storm.kafka.spout;
+
+import org.apache.kafka.common.TopicPartition;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.Serializable;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.concurrent.TimeUnit;
+import org.apache.commons.lang.Validate;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+
+/**
+ * Implementation of {@link KafkaSpoutRetryService} using the exponential
backoff formula. The time of the nextRetry is set as follows:
+ * nextRetry = failCount == 1 ? currentTime + initialDelay : currentTime +
delayPeriod*2^(failCount-1) where failCount = 1, 2, 3, ...
+ * nextRetry = Min(nextRetry, currentTime + maxDelay)
+ */
+public class KafkaSpoutRetryExponentialBackoff implements
KafkaSpoutRetryService {
--- End diff --
Added comment.
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