io.vertx.pgclient.pubsub

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 Summary

Modifier and Type	Method and Description
PgConnection	actualConnection()
PgChannel	channel(String name) Return a channel for the given name.
Future<Void>	close() Like close(Handler) but with a future of the result
void	close(Handler<AsyncResult<Void>> handler) Close the subscriber, the retry policy will not be invoked.
boolean	closed()
PgSubscriber	closeHandler(Handler<Void> handler) Set an handler called when the subscriber is closed.
Future<Void>	connect() Like connect(Handler) but with a future of the result
PgSubscriber	connect(Handler<AsyncResult<Void>> handler) Connect the subscriber to Postgres.
PgSubscriber	reconnectPolicy(java.util.function.Function<Integer,Long> policy) Set the reconnect policy that is executed when the subscriber is disconnected.
static PgSubscriber	subscriber(Vertx vertx, PgConnectOptions options) Create a subscriber.

Method Detail

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()

Like connect(Handler) but with a future of the result

connect

PgSubscriber connect(Handler<AsyncResult<Void>> handler)

Connect the subscriber to Postgres.

Parameters:

handler - the handler notified of the connection success or failure

Returns:

a reference to this, so the API can be used fluently

reconnectPolicy

PgSubscriber reconnectPolicy(java.util.function.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()

Like close(Handler) but with a future of the result

close

void close(Handler<AsyncResult<Void>> handler)

Close the subscriber, the retry policy will not be invoked.