Package org.apache.sling.distribution.journal

Interface MessagingProvider

public interface MessagingProvider
Messaging abstraction for a journal based messaging like Apache Kafka. Messages are represented as json serialisable java classes. The API assumes that each MessagingProvider is mapped to exactly one partition, so positions in a topic can be represented as a single long offset.

  • Method Details

    • createSender

      <T> MessageSender<T> createSender(String topic)
      Create sender for a specific topic
      Type Parameters:
      T - type of the message
      Parameters:
      topic - topic name
      Returns:
      sender

    • createPoller

      default Closeable createPoller(String topicName, Reset reset, HandlerAdapter<?>... adapters)

    • createPoller

      Closeable createPoller(String topicName, Reset reset, String assign, HandlerAdapter<?>... adapters)
      Create a poller which listens to a topic and starts at a given reset or assigned offset.
      Parameters:
      topicName - name of the topic
      reset - fallback in case no assign is given or the assigned offset not valid
      assign - opaque implementation dependent assign string (can be null)
      adapters - list of listener adapters
      Returns:
      closeable handle of the poller

    • createPoller

      default Closeable createPoller(String topicName, Reset reset, String assign, Map<String,String> filterProperties, HandlerAdapter<?>... adapters)
      Create a poller which listens to a topic and starts at a given reset or assigned offset.
      Parameters:
      topicName - name of the topic
      reset - fallback in case no assign is given or the assigned offset not valid
      assign - opaque implementation dependent assign string (can be null)
      filterProperties - List of properties used to filter the topic messages. Only messages that match all filterProperties keys and values will be received.
      adapters - list of listener adapters
      Returns:
      closeable handle of the poller

    • assertTopic

      void assertTopic(String topic) throws MessagingException
      Validate that a topic is suitably set up for the messaging implementation
      Parameters:
      topic - topic name
      Throws:
      MessagingException - exception in case the topic is not suitable

    • retrieveOffset

      long retrieveOffset(String topicName, Reset reset)
      Retrieve earliest or latest offset for a topic
      Parameters:
      topicName - name of the topic
      reset - latest or earliest
      Returns:
      offset

    • assignTo

      String assignTo(long offset)
      Create assign String to feed into poller based on a given offset. The inner format of the assign string is implementation specific.
      Parameters:
      offset -
      Returns:
      assign String

    • assignTo

      String assignTo(Reset reset, long relativeOffset)
      Get assign String to feed into createPoller based on either earliest or latest and a relative offset. The inner format of the assign string is implementation specific.
      Parameters:
      reset - reference point
      relativeOffset - relative offset
      Returns:
      assign String

    • getServerUri

      URI getServerUri()
      Return the uri of the messaging system backend. The uri must be unique regarding the validity of per topic offsets.
      Returns:
      uri