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The Reactive PostgreSQL Client
/*
* Copyright (C) 2017 Julien Viet
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package io.vertx.pgclient.pubsub;
import io.vertx.core.Future;
import io.vertx.pgclient.PgConnectOptions;
import io.vertx.pgclient.PgConnection;
import io.vertx.pgclient.impl.pubsub.PgSubscriberImpl;
import io.vertx.codegen.annotations.Fluent;
import io.vertx.codegen.annotations.VertxGen;
import io.vertx.core.AsyncResult;
import io.vertx.core.Handler;
import io.vertx.core.Vertx;
import java.util.function.Function;
/**
* A class for managing subscriptions using {@code LISTEN/UNLISTEN} to Postgres channels.
*
* The subscriber manages a single connection to Postgres.
*/
@VertxGen
public interface PgSubscriber {
/**
* Create a subscriber.
*
* @param vertx the vertx instance
* @param options the connect options
* @return the subscriber
*/
static PgSubscriber subscriber(Vertx vertx, PgConnectOptions options) {
return new PgSubscriberImpl(vertx, options);
}
/**
* Return a channel for the given {@code name}.
*
* @param 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 {@code (NAMEDATALEN = 64) - 1 == 63} characters, and prepared
* as a quoted identifier without unicode escape sequence support for use in
* {@code LISTEN/UNLISTEN} commands. Examples of channel names and corresponding
* {@code NOTIFY} commands:
*
* - when {@code name == "the_channel"}: {@code NOTIFY the_channel, 'msg'},
* {@code NOTIFY The_Channel, 'msg'}, or {@code NOTIFY "the_channel", 'msg'}
* succeed in delivering a message to the created channel
*
* - when {@code name == "The_Channel"}: {@code NOTIFY "The_Channel", 'msg'},
* succeeds in delivering a message to the created channel
*
*
*
* @return the channel
*/
PgChannel channel(String name);
/**
* Like {@link #connect(Handler)} but with a future of the result
*/
Future connect();
/**
* Connect the subscriber to Postgres.
*
* @param handler the handler notified of the connection success or failure
* @return a reference to this, so the API can be used fluently
*/
@Fluent
PgSubscriber connect(Handler> handler);
/**
* Set the reconnect policy that is executed when the subscriber is disconnected.
*
* When the subscriber is disconnected, the {@code policy} function is called with the actual
* number of retries and returns an {@code amountOfTime} value:
*
* - when {@code amountOfTime < 0}: the subscriber is closed and there is no retry
* - when {@code amountOfTime == 0}: the subscriber retries to connect immediately
* - when {@code amountOfTime > 0}: the subscriber retries after {@code amountOfTime} milliseconds
*
*
* The default policy does not perform any retries.
*
* @param policy the policy to set
* @return a reference to this, so the API can be used fluently
*/
@Fluent
PgSubscriber reconnectPolicy(Function policy);
/**
* Set an handler called when the subscriber is closed.
*
* @param handler the handler
* @return a reference to this, so the API can be used fluently
*/
@Fluent
PgSubscriber closeHandler(Handler handler);
/**
* @return the actual connection to Postgres, it might be {@code null}
*/
PgConnection actualConnection();
/**
* @return whether the subscriber is closed
*/
boolean closed();
/**
* Like {@link #close(Handler)} but with a future of the result
*/
Future close();
/**
* Close the subscriber, the retry policy will not be invoked.
*/
void close(Handler> handler);
}
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