Consumer (Pulsar Client Java API)

All Superinterfaces:

AutoCloseable, Closeable
```
public interface Consumer<T>
extends Closeable
```
An interface that abstracts behavior of Pulsar's consumer.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`acknowledge(Message<?> message)` Acknowledge the consumption of a single message
`void`	`acknowledge(MessageId messageId)` Acknowledge the consumption of a single message, identified by its MessageId
`CompletableFuture<Void>`	`acknowledgeAsync(Message<?> message)` Asynchronously acknowledge the consumption of a single message
`CompletableFuture<Void>`	`acknowledgeAsync(MessageId messageId)` Asynchronously acknowledge the consumption of a single message
`void`	`acknowledgeCumulative(Message<?> message)` Acknowledge the reception of all the messages in the stream up to (and including) the provided message.
`void`	`acknowledgeCumulative(MessageId messageId)` Acknowledge the reception of all the messages in the stream up to (and including) the provided message.
`CompletableFuture<Void>`	`acknowledgeCumulativeAsync(Message<?> message)` Asynchronously Acknowledge the reception of all the messages in the stream up to (and including) the provided message.
`CompletableFuture<Void>`	`acknowledgeCumulativeAsync(MessageId messageId)` Asynchronously Acknowledge the reception of all the messages in the stream up to (and including) the provided message.
`void`	`close()` Close the consumer and stop the broker to push more messages.
`CompletableFuture<Void>`	`closeAsync()` Asynchronously close the consumer and stop the broker to push more messages
`String`	`getConsumerName()` Get the name of consumer.
`ConsumerStats`	`getStats()` Get statistics for the consumer.
`String`	`getSubscription()` Get a subscription for the consumer
`String`	`getTopic()` Get a topic for the consumer
`boolean`	`hasReachedEndOfTopic()` Return true if the topic was terminated and this consumer has already consumed all the messages in the topic.
`boolean`	`isConnected()`
`Message<T>`	`receive()` Receives a single message.
`Message<T>`	`receive(int timeout, TimeUnit unit)` Receive a single message
`CompletableFuture<Message<T>>`	`receiveAsync()` Receive a single message
`void`	`redeliverUnacknowledgedMessages()` Redelivers all the unacknowledged messages.
`void`	`seek(MessageId messageId)` Reset the subscription associated with this consumer to a specific message id.
`CompletableFuture<Void>`	`seekAsync(MessageId messageId)` Reset the subscription associated with this consumer to a specific message id.
`void`	`unsubscribe()` Unsubscribe the consumer
`CompletableFuture<Void>`	`unsubscribeAsync()` Asynchronously unsubscribe the consumer

- Method Detail
  - getTopic
```
String getTopic()
```
    Get a topic for the consumer
    
    Returns:
    
    topic for the consumer
  - getSubscription
```
String getSubscription()
```
    Get a subscription for the consumer
    
    Returns:
    
    subscription for the consumer
  - unsubscribe
```
void unsubscribe()
          throws PulsarClientException
```
    Unsubscribe the consumer
    This call blocks until the consumer is unsubscribed.
    
    Throws:
    
    PulsarClientException
  - unsubscribeAsync
```
CompletableFuture<Void> unsubscribeAsync()
```
    Asynchronously unsubscribe the consumer
    
    Returns:
    
    CompletableFuture for this operation
  - receive
```
Message<T> receive()
            throws PulsarClientException
```
    Receives a single message.
    This calls blocks until a message is available.
    
    Returns:
    
    the received message
    
    Throws:
    
    PulsarClientException.AlreadyClosedException - if the consumer was already closed
    
    PulsarClientException.InvalidConfigurationException - if a message listener was defined in the configuration
    
    PulsarClientException
  - receiveAsync
```
CompletableFuture<Message<T>> receiveAsync()
```
    Receive a single message
    Retrieves a message when it will be available and completes CompletableFuture with received message.
    
    receiveAsync() should be called subsequently once returned CompletableFuture gets complete with received message. Else it creates backlog of receive requests in the application.
    
    Returns:
    
    CompletableFuture<Message> will be completed when message is available
  - receive
```
Message<T> receive(int timeout,
                   TimeUnit unit)
            throws PulsarClientException
```
    Receive a single message
    Retrieves a message, waiting up to the specified wait time if necessary.
    
    Parameters:
    
    timeout - 0 or less means immediate rather than infinite
    
    unit -
    
    Returns:
    
    the received Message or null if no message available before timeout
    
    Throws:
    
    PulsarClientException.AlreadyClosedException - if the consumer was already closed
    
    PulsarClientException.InvalidConfigurationException - if a message listener was defined in the configuration
    
    PulsarClientException
  - acknowledge
```
void acknowledge(Message<?> message)
          throws PulsarClientException
```
    Acknowledge the consumption of a single message
    
    Parameters:
    
    message - The Message to be acknowledged
    
    Throws:
    
    PulsarClientException.AlreadyClosedException - if the consumer was already closed
    
    PulsarClientException
  - acknowledge
```
void acknowledge(MessageId messageId)
          throws PulsarClientException
```
    Acknowledge the consumption of a single message, identified by its MessageId
    
    Parameters:
    
    messageId - The MessageId to be acknowledged
    
    Throws:
    
    PulsarClientException.AlreadyClosedException - if the consumer was already closed
    
    PulsarClientException
  - acknowledgeCumulative
```
void acknowledgeCumulative(Message<?> message)
                    throws PulsarClientException
```
    Acknowledge the reception of all the messages in the stream up to (and including) the provided message. This method will block until the acknowledge has been sent to the broker. After that, the messages will not be re-delivered to this consumer. Cumulative acknowledge cannot be used when the consumer type is set to ConsumerShared. It's equivalent to calling asyncAcknowledgeCumulative(Message) and waiting for the callback to be triggered.
    
    Parameters:
    
    message - The Message to be cumulatively acknowledged
    
    Throws:
    
    PulsarClientException.AlreadyClosedException - if the consumer was already closed
    
    PulsarClientException
  - acknowledgeCumulative
```
void acknowledgeCumulative(MessageId messageId)
                    throws PulsarClientException
```
    Acknowledge the reception of all the messages in the stream up to (and including) the provided message. This method will block until the acknowledge has been sent to the broker. After that, the messages will not be re-delivered to this consumer. Cumulative acknowledge cannot be used when the consumer type is set to ConsumerShared. It's equivalent to calling asyncAcknowledgeCumulative(MessageId) and waiting for the callback to be triggered.
    
    Parameters:
    
    messageId - The MessageId to be cumulatively acknowledged
    
    Throws:
    
    PulsarClientException.AlreadyClosedException - if the consumer was already closed
    
    PulsarClientException
  - acknowledgeAsync
```
CompletableFuture<Void> acknowledgeAsync(Message<?> message)
```
    Asynchronously acknowledge the consumption of a single message
    
    Parameters:
    
    message - The Message to be acknowledged
    
    Returns:
    
    a future that can be used to track the completion of the operation
  - acknowledgeAsync
```
CompletableFuture<Void> acknowledgeAsync(MessageId messageId)
```
    Asynchronously acknowledge the consumption of a single message
    
    Parameters:
    
    messageId - The MessageId to be acknowledged
    
    Returns:
    
    a future that can be used to track the completion of the operation
  - acknowledgeCumulativeAsync
```
CompletableFuture<Void> acknowledgeCumulativeAsync(Message<?> message)
```
    Asynchronously Acknowledge the reception of all the messages in the stream up to (and including) the provided message. Cumulative acknowledge cannot be used when the consumer type is set to ConsumerShared.
    
    Parameters:
    
    message - The Message to be cumulatively acknowledged
    
    Returns:
    
    a future that can be used to track the completion of the operation
  - acknowledgeCumulativeAsync
```
CompletableFuture<Void> acknowledgeCumulativeAsync(MessageId messageId)
```
    Asynchronously Acknowledge the reception of all the messages in the stream up to (and including) the provided message. Cumulative acknowledge cannot be used when the consumer type is set to ConsumerShared.
    
    Parameters:
    
    messageId - The MessageId to be cumulatively acknowledged
    
    Returns:
    
    a future that can be used to track the completion of the operation
  - getStats
```
ConsumerStats getStats()
```
    Get statistics for the consumer.
    - numMsgsReceived : Number of messages received in the current interval
    - numBytesReceived : Number of bytes received in the current interval
    - numReceiveFailed : Number of messages failed to receive in the current interval
    - numAcksSent : Number of acks sent in the current interval
    - numAcksFailed : Number of acks failed to send in the current interval
    - totalMsgsReceived : Total number of messages received
    - totalBytesReceived : Total number of bytes received
    - totalReceiveFailed : Total number of messages failed to receive
    - totalAcksSent : Total number of acks sent
    - totalAcksFailed : Total number of acks failed to sent
    Returns:
    
    statistic for the consumer
  - close
```
void close()
    throws PulsarClientException
```
    Close the consumer and stop the broker to push more messages.
    
    Specified by:
    
    close in interface AutoCloseable
    
    Specified by:
    
    close in interface Closeable
    
    Throws:
    
    PulsarClientException
  - closeAsync
```
CompletableFuture<Void> closeAsync()
```
    Asynchronously close the consumer and stop the broker to push more messages
    
    Returns:
    
    a future that can be used to track the completion of the operation
  - hasReachedEndOfTopic
```
boolean hasReachedEndOfTopic()
```
    Return true if the topic was terminated and this consumer has already consumed all the messages in the topic. Please note that this does not simply mean that the consumer is caught up with the last message published by producers, rather the topic needs to be explicitly "terminated".
  - redeliverUnacknowledgedMessages
```
void redeliverUnacknowledgedMessages()
```
    Redelivers all the unacknowledged messages. In Failover mode, the request is ignored if the consumer is not active for the given topic. In Shared mode, the consumers messages to be redelivered are distributed across all the connected consumers. This is a non blocking call and doesn't throw an exception. In case the connection breaks, the messages are redelivered after reconnect.
  - seek
```
void seek(MessageId messageId)
   throws PulsarClientException
```
    Reset the subscription associated with this consumer to a specific message id.
    The message id can either be a specific message or represent the first or last messages in the topic.
    - MessageId.earliest : Reset the subscription on the earliest message available in the topic
    - MessageId.latest : Reset the subscription on the latest message in the topic
    Note: this operation can only be done on non-partitioned topics. For these, one can rather perform the seek() on the individual partitions.
    Parameters:
    
    messageId - the message id where to reposition the subscription
    
    Throws:
    
    PulsarClientException
  - seekAsync
```
CompletableFuture<Void> seekAsync(MessageId messageId)
```
    Reset the subscription associated with this consumer to a specific message id.
    The message id can either be a specific message or represent the first or last messages in the topic.
    - MessageId.earliest : Reset the subscription on the earliest message available in the topic
    - MessageId.latest : Reset the subscription on the latest message in the topic
    Note: this operation can only be done on non-partitioned topics. For these, one can rather perform the seek() on the individual partitions.
    Parameters:
    
    messageId - the message id where to reposition the subscription
    
    Returns:
    
    a future to track the completion of the seek operation
  - isConnected
```
boolean isConnected()
```
    Returns:
    
    Whether the consumer is connected to the broker
  - getConsumerName
```
String getConsumerName()
```
    Get the name of consumer.
    
    Returns:
    
    consumer name.

Interface Consumer<T>

Method Summary

Method Detail

getTopic

getSubscription

unsubscribe

unsubscribeAsync

receive

receiveAsync

receive

acknowledge

acknowledge

acknowledgeCumulative

acknowledgeCumulative

acknowledgeAsync

acknowledgeAsync

acknowledgeCumulativeAsync

acknowledgeCumulativeAsync

getStats

close

closeAsync

hasReachedEndOfTopic

redeliverUnacknowledgedMessages

seek

seekAsync

isConnected

getConsumerName