io.r2dbc.postgresql.client.Client Maven / Gradle / Ivy
/*
* Copyright 2017-2020 the original author or authors.
*
* 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
*
* https://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.r2dbc.postgresql.client;
import io.netty.buffer.ByteBufAllocator;
import io.r2dbc.postgresql.message.backend.BackendMessage;
import io.r2dbc.postgresql.message.backend.NotificationResponse;
import io.r2dbc.postgresql.message.backend.ReadyForQuery;
import io.r2dbc.postgresql.message.frontend.FrontendMessage;
import io.r2dbc.spi.R2dbcNonTransientResourceException;
import org.reactivestreams.Publisher;
import org.reactivestreams.Subscriber;
import reactor.core.Disposable;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import java.util.Optional;
import java.util.function.Consumer;
import java.util.function.Predicate;
/**
* An abstraction that wraps the networking part of exchanging methods.
*/
public interface Client {
/**
* Add a consumer of notification messages. Notifications received by this connection are sent to the {@link Consumer notification consumer}. Note that connection errors and events such as
* disconnects are not visible to the {@link Consumer notification consumer}.
*
* @param consumer the consumer of notification messages
* @return a new {@link Disposable} that can be used to cancel the underlying subscription.
* @throws IllegalArgumentException if {@code consumer} is {@code null}
*/
Disposable addNotificationListener(Consumer consumer);
/**
* Add a consumer of notification messages. Notifications received by this connection are sent to the {@link Subscriber notification listener}. When the client gets {@link #close() closed}, the
* subscription {@link Subscriber#onComplete() completes normally}. Otherwise (transport connection disconnected unintentionally) with an {@link R2dbcNonTransientResourceException error}.
*
* @param consumer the consumer of notification messages
* @return a new {@link Disposable} that can be used to cancel the underlying subscription.
* @throws IllegalArgumentException if {@code consumer} is {@code null}
* @since 0.8.1
*/
Disposable addNotificationListener(Subscriber consumer);
/**
* Release any resources held by the {@link Client}.
*
* @return a {@link Mono} that indicates that a client has been closed
*/
Mono close();
/**
* Perform an exchange of messages. Note that the {@link ReadyForQuery} frame is not emitted through the resulting {@link Flux}.
*
* @param requests the publisher of outbound messages
* @return a {@link Flux} of incoming messages that ends with the end of conversation (i.e. reception of a {@link ReadyForQuery} message. Th
* @throws IllegalArgumentException if {@code requests} is {@code null}
*/
default Flux exchange(Publisher requests) {
return this.exchange(it -> it.getClass() == ReadyForQuery.class, requests);
}
/**
* Perform an exchange of messages.
*
* @param takeUntil the predicate that signals the resulting {@link Flux} to terminate. Typically a check if the {@link BackendMessage} is the last frame of a conversation. Note that the
* {@link BackendMessage} that matches the predicate is not emitted through the resulting {@link Flux}.
* @param requests the publisher of outbound messages
* @return a {@link Flux} of incoming messages that ends with the end of conversation matching {@code takeUntil}. (i.e. reception of a {@link ReadyForQuery} message.
* @throws IllegalArgumentException if {@code requests} is {@code null}
* @since 0.8.1
*/
Flux exchange(Predicate takeUntil, Publisher requests);
/**
* Send one message without waiting for response.
*
* @param message outbound message
* @throws IllegalArgumentException if {@code message} is {@code null}
* @since 0.8.1
*/
void send(FrontendMessage message);
/**
* Returns the {@link ByteBufAllocator}.
*
* @return the {@link ByteBufAllocator}
*/
ByteBufAllocator getByteBufAllocator();
/**
* Returns the connected process id if it has been communicated.
*
* @return the connected process id if it has been communicated
*/
Optional getProcessId();
/**
* Returns the connected process secret key if it has been communicated.
*
* @return the connected process secret key if it has been communicated
*/
Optional getSecretKey();
/**
* Returns the current transaction status.
*
* @return the current transaction status
*/
TransactionStatus getTransactionStatus();
/**
* Return the server version.
*
* @return the server version from {@code server_version}/{@code server_version_num} startup parameters.
*/
Version getVersion();
/**
* Returns whether the client is connected to a server.
*
* @return {@literal true} if the client is connected to a server.
*/
boolean isConnected();
}