org.apache.kafka.common.utils.CollectionUtils Maven / Gradle / Ivy
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* 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.kafka.common.utils;
import org.apache.kafka.common.TopicPartition;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Collection;
import java.util.stream.Collectors;
public final class CollectionUtils {
private CollectionUtils() {}
/**
* Given two maps (A, B), returns all the key-value pairs in A whose keys are not contained in B
*/
public static Map subtractMap(Map minuend, Map subtrahend) {
return minuend.entrySet().stream()
.filter(entry -> !subtrahend.containsKey(entry.getKey()))
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
}
/**
* group data by topic
*
* @param data Data to be partitioned
* @param Partition data type
* @return partitioned data
*/
public static Map> groupPartitionDataByTopic(Map data) {
Map> dataByTopic = new HashMap<>();
for (Map.Entry entry : data.entrySet()) {
String topic = entry.getKey().topic();
int partition = entry.getKey().partition();
Map topicData = dataByTopic.computeIfAbsent(topic, t -> new HashMap<>());
topicData.put(partition, entry.getValue());
}
return dataByTopic;
}
/**
* Group a list of partitions by the topic name.
*
* @param partitions The partitions to collect
* @return partitions per topic
*/
public static Map> groupPartitionsByTopic(Collection partitions) {
Map> partitionsByTopic = new HashMap<>();
for (TopicPartition tp : partitions) {
String topic = tp.topic();
List topicData = partitionsByTopic.computeIfAbsent(topic, t -> new ArrayList<>());
topicData.add(tp.partition());
}
return partitionsByTopic;
}
}