Interface PgSubscriber

public interface PgSubscriber
A class for managing subscriptions using LISTEN/UNLISTEN to Postgres channels.

The subscriber manages a single connection to Postgres.

  • Method Details

    • subscriber

      static PgSubscriber subscriber(Vertx vertx, PgConnectOptions options)
      Create a subscriber.
      Parameters:
      vertx - the vertx instance
      options - the connect options
      Returns:
      the subscriber

    • channel

      PgChannel channel(String name)
      Return a channel for the given name.
      Parameters:
      name - the channel name

      This will be the name of the channel exactly as held by Postgres for sending notifications. Internally this name will be truncated to the Postgres identifier maxiumum length of (NAMEDATALEN = 64) - 1 == 63 characters, and prepared as a quoted identifier without unicode escape sequence support for use in LISTEN/UNLISTEN commands. Examples of channel names and corresponding NOTIFY commands:

      • when name == "the_channel": NOTIFY the_channel, 'msg', NOTIFY The_Channel, 'msg', or NOTIFY "the_channel", 'msg' succeed in delivering a message to the created channel
      • when name == "The_Channel": NOTIFY "The_Channel", 'msg', succeeds in delivering a message to the created channel
      Returns:
      the channel

    • connect

      Future<Void> connect()
      Connect the subscriber to Postgres.
      Returns:
      a future notified of the connection success or failure

    • reconnectPolicy

      PgSubscriber reconnectPolicy(Function<Integer,Long> policy)
      Set the reconnect policy that is executed when the subscriber is disconnected.

      When the subscriber is disconnected, the policy function is called with the actual number of retries and returns an amountOfTime value:

      • when amountOfTime < 0: the subscriber is closed and there is no retry
      • when amountOfTime == 0: the subscriber retries to connect immediately
      • when amountOfTime > 0: the subscriber retries after amountOfTime milliseconds

      The default policy does not perform any retries.

      Parameters:
      policy - the policy to set
      Returns:
      a reference to this, so the API can be used fluently

    • closeHandler

      PgSubscriber closeHandler(Handler<Void> handler)
      Set an handler called when the subscriber is closed.
      Parameters:
      handler - the handler
      Returns:
      a reference to this, so the API can be used fluently

    • actualConnection

      PgConnection actualConnection()
      Returns:
      the actual connection to Postgres, it might be null

    • closed

      boolean closed()
      Returns:
      whether the subscriber is closed

    • close

      Future<Void> close()
      Close the subscriber, the retry policy will not be invoked.