org.apache.kafka.clients.consumer.internals.PartitionAssignorAdapter Maven / Gradle / Ivy
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* 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,
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* See the License for the specific language governing permissions and
* limitations under the License.
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package org.apache.kafka.clients.consumer.internals;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.kafka.clients.consumer.ConsumerGroupMetadata;
import org.apache.kafka.clients.consumer.ConsumerPartitionAssignor;
import org.apache.kafka.common.Cluster;
import org.apache.kafka.common.Configurable;
import org.apache.kafka.common.KafkaException;
import org.apache.kafka.common.utils.Utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This adapter class is used to ensure backwards compatibility for those who have implemented the {@link PartitionAssignor}
* interface, which has been deprecated in favor of the new {@link org.apache.kafka.clients.consumer.ConsumerPartitionAssignor}.
*
* Note that maintaining compatibility for an internal interface here is a special case, as {@code PartitionAssignor}
* was meant to be a public API although it was placed in the internals package. Users should not expect internal
* interfaces or classes to not be removed or maintain compatibility in any way.
*/
@SuppressWarnings("deprecation")
public class PartitionAssignorAdapter implements ConsumerPartitionAssignor {
private static final Logger LOG = LoggerFactory.getLogger(PartitionAssignorAdapter.class);
private final PartitionAssignor oldAssignor;
PartitionAssignorAdapter(PartitionAssignor oldAssignor) {
this.oldAssignor = oldAssignor;
}
@Override
public ByteBuffer subscriptionUserData(Set topics) {
return oldAssignor.subscription(topics).userData();
}
@Override
public GroupAssignment assign(Cluster metadata, GroupSubscription groupSubscription) {
return toNewGroupAssignment(oldAssignor.assign(metadata, toOldGroupSubscription(groupSubscription)));
}
@Override
public void onAssignment(Assignment assignment, ConsumerGroupMetadata metadata) {
oldAssignor.onAssignment(toOldAssignment(assignment), metadata.generationId());
}
@Override
public String name() {
return oldAssignor.name();
}
private static PartitionAssignor.Assignment toOldAssignment(Assignment newAssignment) {
return new PartitionAssignor.Assignment(newAssignment.partitions(), newAssignment.userData());
}
private static Map toOldGroupSubscription(GroupSubscription newSubscriptions) {
Map oldSubscriptions = new HashMap<>();
for (Map.Entry entry : newSubscriptions.groupSubscription().entrySet()) {
String member = entry.getKey();
Subscription newSubscription = entry.getValue();
oldSubscriptions.put(member, new PartitionAssignor.Subscription(
newSubscription.topics(), newSubscription.userData()));
}
return oldSubscriptions;
}
private static GroupAssignment toNewGroupAssignment(Map oldAssignments) {
Map newAssignments = new HashMap<>();
for (Map.Entry entry : oldAssignments.entrySet()) {
String member = entry.getKey();
PartitionAssignor.Assignment oldAssignment = entry.getValue();
newAssignments.put(member, new Assignment(oldAssignment.partitions(), oldAssignment.userData()));
}
return new GroupAssignment(newAssignments);
}
/**
* Get a list of configured instances of {@link org.apache.kafka.clients.consumer.ConsumerPartitionAssignor}
* based on the class names/types specified by {@link org.apache.kafka.clients.consumer.ConsumerConfig#PARTITION_ASSIGNMENT_STRATEGY_CONFIG}
* where any instances of the old {@link PartitionAssignor} interface are wrapped in an adapter to the new
* {@link org.apache.kafka.clients.consumer.ConsumerPartitionAssignor} interface
*/
public static List getAssignorInstances(List assignorClasses, Map configs) {
List assignors = new ArrayList<>();
if (assignorClasses == null)
return assignors;
for (Object klass : assignorClasses) {
// first try to get the class if passed in as a string
if (klass instanceof String) {
try {
klass = Class.forName((String) klass, true, Utils.getContextOrKafkaClassLoader());
} catch (ClassNotFoundException classNotFound) {
throw new KafkaException(klass + " ClassNotFoundException exception occurred", classNotFound);
}
}
if (klass instanceof Class) {
Object assignor = Utils.newInstance((Class) klass);
if (assignor instanceof Configurable)
((Configurable) assignor).configure(configs);
if (assignor instanceof ConsumerPartitionAssignor) {
assignors.add((ConsumerPartitionAssignor) assignor);
} else if (assignor instanceof PartitionAssignor) {
assignors.add(new PartitionAssignorAdapter((PartitionAssignor) assignor));
LOG.warn("The PartitionAssignor interface has been deprecated, "
+ "please implement the ConsumerPartitionAssignor interface instead.");
} else {
throw new KafkaException(klass + " is not an instance of " + PartitionAssignor.class.getName()
+ " or an instance of " + ConsumerPartitionAssignor.class.getName());
}
} else {
throw new KafkaException("List contains element of type " + klass.getClass().getName() + ", expected String or Class");
}
}
return assignors;
}
}