public interface ChatRoomFactory
{
- Mono<ChatRoom> createChatRoom(UUID id, String name);
+ Mono<ChatRoomInfo> createChatRoom(UUID id, String name);
}
@Override
- public Mono<ChatRoom> createChatRoom(UUID id, String name)
+ public Mono<ChatRoomInfo> createChatRoom(UUID id, String name)
{
log.info("Creating ChatRoom with buffer-size {}", bufferSize);
int shard = shardingStrategy.selectShard(id);
--- /dev/null
+package de.juplo.kafka.chat.backend.persistence.kafka;
+
+import de.juplo.kafka.chat.backend.domain.ChatRoom;
+import de.juplo.kafka.chat.backend.domain.Message;
+import de.juplo.kafka.chat.backend.persistence.KafkaLikeShardingStrategy;
+import lombok.Getter;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.Consumer;
+import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.clients.consumer.ConsumerRecords;
+import org.apache.kafka.clients.producer.Producer;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.errors.RecordDeserializationException;
+import org.apache.kafka.common.errors.WakeupException;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import java.time.*;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import java.util.stream.IntStream;
+
+
+@Slf4j
+public class ChatMessageChannel implements Runnable, ConsumerRebalanceListener
+{
+ private final String topic;
+ private final Consumer<String, MessageTo> consumer;
+ private final Producer<String, MessageTo> producer;
+ private final ZoneId zoneId;
+ private final int numShards;
+ private final boolean[] isShardOwned;
+ private final long[] currentOffset;
+ private final long[] nextOffset;
+ private final Map<UUID, ChatRoom>[] chatrooms;
+ private final KafkaLikeShardingStrategy shardingStrategy;
+
+ private boolean running;
+ @Getter
+ private volatile boolean loadInProgress;
+
+
+ public ChatMessageChannel(
+ String topic,
+ Consumer<String, MessageTo> consumer,
+ Producer<String, MessageTo> producer,
+ ZoneId zoneId,
+ int numShards)
+ {
+ log.debug(
+ "Creating ChatMessageChannel for topic {} with {} partitions",
+ topic,
+ numShards);
+ this.topic = topic;
+ this.consumer = consumer;
+ this.producer = producer;
+ this.zoneId = zoneId;
+ this.numShards = numShards;
+ this.isShardOwned = new boolean[numShards];
+ this.currentOffset = new long[numShards];
+ this.nextOffset = new long[numShards];
+ this.chatrooms = new Map[numShards];
+ this.shardingStrategy = new KafkaLikeShardingStrategy(numShards);
+ }
+
+
+ @Override
+ public void onPartitionsAssigned(Collection<TopicPartition> partitions)
+ {
+ log.info("Newly assigned partitions! Pausing normal operations...");
+ loadInProgress = true;
+
+ consumer.endOffsets(partitions).forEach((topicPartition, currentOffset) ->
+ {
+ int partition = topicPartition.partition();
+ isShardOwned[partition] = true;
+ this.currentOffset[partition] = currentOffset;
+
+ log.info(
+ "Partition assigned: {} - loading messages: next={} -> current={}",
+ partition,
+ nextOffset[partition],
+ currentOffset);
+
+ consumer.seek(topicPartition, nextOffset[partition]);
+ });
+
+ consumer.resume(partitions);
+ }
+
+ @Override
+ public void onPartitionsRevoked(Collection<TopicPartition> partitions)
+ {
+ partitions.forEach(topicPartition ->
+ {
+ int partition = topicPartition.partition();
+ isShardOwned[partition] = false;
+ log.info("Partition revoked: {} - next={}", partition, nextOffset[partition]);
+ });
+ }
+
+ @Override
+ public void onPartitionsLost(Collection<TopicPartition> partitions)
+ {
+ log.warn("Lost partitions: {}, partitions");
+ // TODO: Muss auf den Verlust anders reagiert werden?
+ onPartitionsRevoked(partitions);
+ }
+
+ @Override
+ public void run()
+ {
+ consumer.subscribe(List.of(topic));
+
+ running = true;
+
+ while (running)
+ {
+ try
+ {
+ ConsumerRecords<String, MessageTo> records = consumer.poll(Duration.ofMinutes(5));
+ log.info("Fetched {} messages", records.count());
+
+ if (loadInProgress)
+ {
+ loadMessages(records);
+
+ if (isLoadingCompleted())
+ {
+ log.info("Loading of messages completed! Pausing all owned partitions...");
+ pauseAllOwnedPartions();
+ log.info("Resuming normal operations...");
+ loadInProgress = false;
+ }
+ }
+ else
+ {
+ if (!records.isEmpty())
+ {
+ throw new IllegalStateException("All owned partitions should be paused, when no load is in progress!");
+ }
+ }
+ }
+ catch (WakeupException e)
+ {
+ }
+ catch (RecordDeserializationException e)
+ {
+ }
+ }
+ }
+
+ void loadMessages(ConsumerRecords<String, MessageTo> records)
+ {
+ for (ConsumerRecord<String, MessageTo> record : records)
+ {
+ nextOffset[record.partition()] = record.offset() + 1;
+ UUID chatRoomId = UUID.fromString(record.key());
+ MessageTo messageTo = record.value();
+
+ Message.MessageKey key = Message.MessageKey.of(messageTo.getUser(), messageTo.getId());
+
+ Instant instant = Instant.ofEpochSecond(record.timestamp());
+ LocalDateTime timestamp = LocalDateTime.ofInstant(instant, zoneId);
+
+ Message message = new Message(key, record.offset(), timestamp, messageTo.getText());
+
+ ChatRoom chatRoom = chatrooms[record.partition()].get(chatRoomId);
+ if (chatRoom == null)
+ {
+ // Alles pausieren und erst von putChatRoom wieder resumen lassen!
+ }
+ KafkaChatRoomService kafkaChatRoomService =
+ (KafkaChatRoomService) chatRoom.getChatRoomService();
+
+ kafkaChatRoomService.persistMessage(message);
+ }
+ }
+
+ boolean isLoadingCompleted()
+ {
+ return IntStream
+ .range(0, numShards)
+ .filter(shard -> isShardOwned[shard])
+ .mapToObj(shard -> nextOffset[shard] >= currentOffset[shard])
+ .collect(
+ () -> Boolean.TRUE, // TODO: Boolean is immutable
+ (acc, v) -> Boolean.valueOf(acc && v), // TODO: Boolean is immutable
+ (a, b) -> Boolean.valueOf(a && b)); // TODO: Boolean is immutable
+ }
+
+ void pauseAllOwnedPartions()
+ {
+ consumer.pause(IntStream
+ .range(0, numShards)
+ .filter(shard -> isShardOwned[shard])
+ .mapToObj(shard -> new TopicPartition(topic, shard))
+ .toList());
+ }
+
+ Mono<Message> sendMessage(
+ UUID chatRoomId,
+ Message.MessageKey key,
+ LocalDateTime timestamp,
+ String text)
+ {
+ int shard = this.shardingStrategy.selectShard(chatRoomId);
+ TopicPartition tp = new TopicPartition(topic, shard);
+ ZonedDateTime zdt = ZonedDateTime.of(timestamp, zoneId);
+ return Mono.create(sink ->
+ {
+ ProducerRecord<String, MessageTo> record =
+ new ProducerRecord<>(
+ tp.topic(),
+ tp.partition(),
+ zdt.toEpochSecond(),
+ chatRoomId.toString(),
+ MessageTo.of(key.getUsername(), key.getMessageId(), text));
+
+ producer.send(record, ((metadata, exception) ->
+ {
+ if (metadata != null)
+ {
+ // On successful send
+ Message message = new Message(key, metadata.offset(), timestamp, text);
+ log.info("Successfully send message {}", message);
+ sink.success(message);
+ }
+ else
+ {
+ // On send-failure
+ log.error(
+ "Could not send message for chat-room={}, key={}, timestamp={}, text={}: {}",
+ chatRoomId,
+ key,
+ timestamp,
+ text,
+ exception);
+ sink.error(exception);
+ }
+ }));
+ });
+ }
+
+
+ void putChatRoom(ChatRoom chatRoom)
+ {
+ chatrooms[chatRoom.getShard()].put(chatRoom.getId(), chatRoom);
+ }
+
+ Mono<ChatRoom> getChatRoom(int shard, UUID id)
+ {
+ return Mono.justOrEmpty(chatrooms[shard].get(id));
+ }
+
+ Flux<ChatRoom> getChatRooms(int shard)
+ {
+ return Flux.fromStream(chatrooms[shard].values().stream());
+ }
+}
--- /dev/null
+package de.juplo.kafka.chat.backend.persistence.kafka;
+
+import de.juplo.kafka.chat.backend.domain.*;
+import de.juplo.kafka.chat.backend.persistence.KafkaLikeShardingStrategy;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.Consumer;
+import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.clients.consumer.ConsumerRecords;
+import org.apache.kafka.clients.producer.Producer;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.errors.RecordDeserializationException;
+import org.apache.kafka.common.errors.WakeupException;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import java.time.*;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import java.util.stream.IntStream;
+
+
+@Slf4j
+public class ChatRoomChannel implements Runnable
+{
+ private final String topic;
+ private final Consumer<Integer, ChatRoomTo> consumer;
+ private final Producer<Integer, ChatRoomTo> producer;
+ private final ShardingStrategy shardingStrategy;
+ private final ChatMessageChannel chatMessageChannel;
+
+ private boolean running;
+
+
+ public ChatRoomChannel(
+ String topic,
+ Consumer<Integer, ChatRoomTo> consumer,
+ Producer<Integer, ChatRoomTo> producer,
+ int numShards,
+ ChatMessageChannel chatMessageChannel)
+ {
+ log.debug(
+ "Creating ChatRoomChannel for topic {} with sharding for {} partitions",
+ topic,
+ numShards);
+ this.topic = topic;
+ this.consumer = consumer;
+ this.producer = producer;
+ this.shardingStrategy = new KafkaLikeShardingStrategy(numShards);
+ this.chatMessageChannel = chatMessageChannel;
+ }
+
+
+ @Override
+ public void run()
+ {
+ consumer.assign(List.of(new TopicPartition(topic, 0)));
+
+ running = true;
+
+ while (running)
+ {
+ try
+ {
+ ConsumerRecords<String, MessageTo> records = consumer.poll(Duration.ofMinutes(5));
+ log.info("Fetched {} messages", records.count());
+
+ }
+ catch (WakeupException e)
+ {
+ }
+ catch (RecordDeserializationException e)
+ {
+ }
+ }
+ }
+
+
+ Mono<ChatRoomInfo> sendCreateChatRoomRequest(
+ UUID chatRoomId,
+ String name)
+ {
+ int shard = this.shardingStrategy.selectShard(chatRoomId);
+ ChatRoomTo chatRoomTo = ChatRoomTo.of(chatRoomId, name, shard);
+ return Mono.create(sink ->
+ {
+ ProducerRecord<Integer, ChatRoomTo> record =
+ new ProducerRecord<>(
+ topic,
+ shard,
+ chatRoomTo);
+
+ producer.send(record, ((metadata, exception) ->
+ {
+ if (metadata != null)
+ {
+ log.info("Successfully send chreate-request {}", chatRoomTo);
+ sink.success(chatRoomTo.toChatRoomInfo());
+ }
+ else
+ {
+ // On send-failure
+ log.error(
+ "Could not create-request for chat-room={}, key={}, timestamp={}, text={}: {}",
+ chatRoomId,
+ key,
+ timestamp,
+ text,
+ exception);
+ sink.error(exception);
+ }
+ }));
+ });
+ }
+}
package de.juplo.kafka.chat.backend.persistence.kafka;
import de.juplo.kafka.chat.backend.domain.ChatRoom;
+import de.juplo.kafka.chat.backend.domain.ChatRoomInfo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
private String name;
private int shard;
- public ChatRoom toChatRoom(
- Clock clock,
- KafkaChatRoomService service,
- int bufferSize)
+ public ChatRoomInfo toChatRoomInfo()
{
- return new ChatRoom(id, name, shard, clock, service, bufferSize);
+ return new ChatRoomInfo(id, name, shard);
}
public static ChatRoomTo from(ChatRoom chatRoom)
import de.juplo.kafka.chat.backend.domain.ChatHomeService;
import de.juplo.kafka.chat.backend.domain.ChatRoom;
-import de.juplo.kafka.chat.backend.domain.Message;
import de.juplo.kafka.chat.backend.domain.ShardNotOwnedException;
-import de.juplo.kafka.chat.backend.persistence.KafkaLikeShardingStrategy;
import lombok.extern.slf4j.Slf4j;
-import org.apache.kafka.clients.consumer.Consumer;
-import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
-import org.apache.kafka.clients.consumer.ConsumerRecord;
-import org.apache.kafka.clients.consumer.ConsumerRecords;
-import org.apache.kafka.clients.producer.Producer;
-import org.apache.kafka.clients.producer.ProducerRecord;
-import org.apache.kafka.common.TopicPartition;
-import org.apache.kafka.common.errors.RecordDeserializationException;
-import org.apache.kafka.common.errors.WakeupException;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
-import java.time.*;
import java.util.*;
-import java.util.stream.IntStream;
@Slf4j
-public class KafkaChatHomeService implements ChatHomeService, Runnable, ConsumerRebalanceListener
+public class KafkaChatHomeService implements ChatHomeService
{
- private final String chatRoomsTopic;
- private final Consumer<Integer, ChatRoomTo> chatRoomsConsumer;
- private final Producer<Integer, ChatRoomTo> chatRoomsProducer;
- private final String chatMessagesTopic;
- private final Consumer<String, MessageTo> chatMessagesConsumer;
- private final Producer<String, MessageTo> chatMessagesProducer;
- private final ZoneId zoneId;
- private final int numShards;
- private final boolean[] isShardOwned;
- private final long[] currentOffset;
- private final long[] nextOffset;
- private final Map<UUID, ChatRoom>[] chatrooms;
- private final KafkaLikeShardingStrategy shardingStrategy;
+ private final ChatMessageChannel chatMessageChanel;
- private boolean running;
- private volatile boolean loadInProgress;
-
- public KafkaChatHomeService(
- String chatRoomsTopic,
- Consumer<Integer, ChatRoomTo> chatRoomsConsumer,
- Producer<Integer, ChatRoomTo> chatRoomsProducer,
- String chatMessagesTopic,
- Consumer<String, MessageTo> chatMessagesConsumer,
- Producer<String, MessageTo> chatMessagesProducer,
- ZoneId zoneId,
- int numShards)
+ public KafkaChatHomeService(ChatMessageChannel chatMessageChannel)
{
log.debug("Creating KafkaChatHomeService");
- this.chatRoomsTopic = chatRoomsTopic;
- this.chatRoomsConsumer = chatRoomsConsumer;
- this.chatRoomsProducer = chatRoomsProducer;
- this.chatMessagesTopic = chatMessagesTopic;
- this.chatMessagesConsumer = chatMessagesConsumer;
- this.chatMessagesProducer = chatMessagesProducer;
- this.zoneId = zoneId;
- this.numShards = numShards;
- this.isShardOwned = new boolean[numShards];
- this.currentOffset = new long[numShards];
- this.nextOffset = new long[numShards];
- this.chatrooms = new Map[numShards];
- this.shardingStrategy = new KafkaLikeShardingStrategy(numShards);
- }
-
-
- @Override
- public void onPartitionsAssigned(Collection<TopicPartition> partitions)
- {
- log.info("Newly assigned partitions! Pausing normal operations...");
- loadInProgress = true;
-
- chatMessagesConsumer.endOffsets(partitions).forEach((topicPartition, currentOffset) ->
- {
- int partition = topicPartition.partition();
- isShardOwned[partition] = true;
- this.currentOffset[partition] = currentOffset;
-
- log.info(
- "Partition assigned: {} - loading messages: next={} -> current={}",
- partition,
- nextOffset[partition],
- currentOffset);
-
- chatMessagesConsumer.seek(topicPartition, nextOffset[partition]);
- });
-
- chatMessagesConsumer.resume(partitions);
- }
-
- @Override
- public void onPartitionsRevoked(Collection<TopicPartition> partitions)
- {
- partitions.forEach(topicPartition ->
- {
- int partition = topicPartition.partition();
- isShardOwned[partition] = false;
- log.info("Partition revoked: {} - next={}", partition, nextOffset[partition]);
- });
+ this.chatMessageChanel = chatMessageChannel;
}
- @Override
- public void onPartitionsLost(Collection<TopicPartition> partitions)
- {
- log.warn("Lost partitions: {}, partitions");
- // TODO: Muss auf den Verlust anders reagiert werden?
- onPartitionsRevoked(partitions);
- }
-
- @Override
- public void run()
- {
- chatMessagesConsumer.subscribe(List.of(chatMessagesTopic));
-
- running = true;
-
- while (running)
- {
- try
- {
- ConsumerRecords<String, MessageTo> records = chatMessagesConsumer.poll(Duration.ofMinutes(5));
- log.info("Fetched {} messages", records.count());
-
- if (loadInProgress)
- {
- loadMessages(records);
-
- if (isLoadingCompleted())
- {
- log.info("Loading of messages completed! Pausing all owned partitions...");
- pauseAllOwnedPartions();
- log.info("Resuming normal operations...");
- loadInProgress = false;
- }
- }
- else
- {
- if (!records.isEmpty())
- {
- throw new IllegalStateException("All owned partitions should be paused, when no load is in progress!");
- }
- }
- }
- catch (WakeupException e)
- {
- }
- catch (RecordDeserializationException e)
- {
- }
- }
- }
-
- void loadMessages(ConsumerRecords<String, MessageTo> records)
- {
- for (ConsumerRecord<String, MessageTo> record : records)
- {
- nextOffset[record.partition()] = record.offset() + 1;
- UUID chatRoomId = UUID.fromString(record.key());
- MessageTo messageTo = record.value();
-
- Message.MessageKey key = Message.MessageKey.of(messageTo.getUser(), messageTo.getId());
-
- Instant instant = Instant.ofEpochSecond(record.timestamp());
- LocalDateTime timestamp = LocalDateTime.ofInstant(instant, zoneId);
-
- Message message = new Message(key, record.offset(), timestamp, messageTo.getText());
-
- ChatRoom chatRoom = chatrooms[record.partition()].get(chatRoomId);
- KafkaChatRoomService kafkaChatRoomService =
- (KafkaChatRoomService) chatRoom.getChatRoomService();
-
- kafkaChatRoomService.persistMessage(message);
- }
- }
-
- boolean isLoadingCompleted()
- {
- return IntStream
- .range(0, numShards)
- .filter(shard -> isShardOwned[shard])
- .mapToObj(shard -> nextOffset[shard] >= currentOffset[shard])
- .collect(
- () -> Boolean.TRUE,
- (acc, v) -> Boolean.valueOf(acc && v),
- (a, b) -> Boolean.valueOf(a && b));
- }
-
- void pauseAllOwnedPartions()
- {
- chatMessagesConsumer.pause(IntStream
- .range(0, numShards)
- .filter(shard -> isShardOwned[shard])
- .mapToObj(shard -> new TopicPartition(chatMessagesTopic, shard))
- .toList());
- }
-
- Mono<Message> sendMessage(
- UUID chatRoomId,
- Message.MessageKey key,
- LocalDateTime timestamp,
- String text)
- {
- int shard = this.shardingStrategy.selectShard(chatRoomId);
- TopicPartition tp = new TopicPartition(chatMessagesTopic, shard);
- ZonedDateTime zdt = ZonedDateTime.of(timestamp, zoneId);
- return Mono.create(sink ->
- {
- ProducerRecord<String, MessageTo> record =
- new ProducerRecord<>(
- tp.topic(),
- tp.partition(),
- zdt.toEpochSecond(),
- chatRoomId.toString(),
- MessageTo.of(key.getUsername(), key.getMessageId(), text));
-
- chatMessagesProducer.send(record, ((metadata, exception) ->
- {
- if (metadata != null)
- {
- // On successful send
- Message message = new Message(key, metadata.offset(), timestamp, text);
- log.info("Successfully send message {}", message);
- sink.success(message);
- }
- else
- {
- // On send-failure
- log.error(
- "Could not send message for chat-room={}, key={}, timestamp={}, text={}: {}",
- chatRoomId,
- key,
- timestamp,
- text,
- exception);
- sink.error(exception);
- }
- }));
- });
- }
-
-
- public void putChatRoom(ChatRoom chatRoom)
- {
-
- ProducerRecord<Integer, ChatRoomTo> record = new ProducerRecord<>(chatRoom.getShard(), );
- // TODO: Nachricht senden!
- chatrooms[chatRoom.getShard()].put(chatRoom.getId(), chatRoom);
- }
@Override
public Mono<ChatRoom> getChatRoom(int shard, UUID id)
{
- if (loadInProgress)
+ if (chatMessageChanel.isLoadInProgress())
{
throw new ShardNotOwnedException(shard);
}
else
{
- return Mono.justOrEmpty(chatrooms[shard].get(id));
+ return chatMessageChanel.getChatRoom(shard, id);
}
}
@Override
public Flux<ChatRoom> getChatRooms(int shard)
{
- if (loadInProgress)
+ if (chatMessageChanel.isLoadInProgress())
{
throw new ShardNotOwnedException(shard);
}
else
{
- return Flux.fromStream(chatrooms[shard].values().stream());
+ return chatMessageChanel.getChatRooms(shard);
}
}
}
import de.juplo.kafka.chat.backend.domain.ChatRoom;
import de.juplo.kafka.chat.backend.domain.ChatRoomFactory;
-import de.juplo.kafka.chat.backend.domain.ChatRoomService;
+import de.juplo.kafka.chat.backend.domain.ChatRoomInfo;
import de.juplo.kafka.chat.backend.domain.ShardingStrategy;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
@Slf4j
public class KafkaChatRoomFactory implements ChatRoomFactory
{
- private final KafkaChatHomeService kafkaChatHomeService;
- private final ShardingStrategy shardingStrategy;
- private final Clock clock;
- private final int bufferSize;
+ private final ChatRoomChannel chatRoomChannel;
@Override
- public Mono<ChatRoom> createChatRoom(UUID id, String name)
+ public Mono<ChatRoomInfo> createChatRoom(UUID id, String name)
{
log.info("Creating ChatRoom with buffer-size {}", bufferSize);
- int shard = shardingStrategy.selectShard(id);
- KafkaChatRoomService service = new KafkaChatRoomService(kafkaChatHomeService, id);
+ KafkaChatRoomService service = new KafkaChatRoomService(chatRoomChannel, id);
ChatRoom chatRoom = new ChatRoom(id, name, shard, clock, service, bufferSize);
- kafkaChatHomeService.putChatRoom(chatRoom);
+ chatRoomChannel.putChatRoom(chatRoom);
+ return Mono.just(chatRoom);
}
}
@Slf4j
public class KafkaChatRoomService implements ChatRoomService
{
- private final KafkaChatHomeService kafkaChatHomeService;
+ private final ChatMessageChannel chatMessageChannel;
private final UUID chatRoomId;
private final LinkedHashMap<Message.MessageKey, Message> messages = new LinkedHashMap<>();
LocalDateTime timestamp,
String text)
{
- return kafkaChatHomeService
+ return chatMessageChannel
.sendMessage(chatRoomId, key, timestamp, text)
.doOnSuccess(message -> persistMessage(message));
}
public void persistMessage(Message message)
{
- messages.put(message.getKey(), message)
+ messages.put(message.getKey(), message);
}
@Override
synchronized public Mono<Message> getMessage(Message.MessageKey key)
{
- // TODO: Aufrufe, auf eine Nachricht (einge gewisse Zeit) warten lassen
- // und dann bedienen, wenn der der Callback vom Producer aufgerufen wird?
return Mono.fromSupplier(() -> messages.get(key));
}
projects / demos / kafka / chat / commitdiff