Java tutorial
/* * Copyright 2015 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 * * 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.atomix.catalyst.transport.netty; import io.atomix.catalyst.concurrent.ComposableFuture; import io.atomix.catalyst.concurrent.ThreadContext; import io.atomix.catalyst.transport.Address; import io.atomix.catalyst.transport.Client; import io.atomix.catalyst.transport.Connection; import io.atomix.catalyst.util.Assert; import io.netty.bootstrap.Bootstrap; import io.netty.buffer.ByteBufAllocator; import io.netty.buffer.PooledByteBufAllocator; import io.netty.channel.*; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioSocketChannel; import io.netty.handler.codec.LengthFieldBasedFrameDecoder; import io.netty.handler.codec.LengthFieldPrepender; import io.netty.handler.ssl.SslHandler; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.Map; import java.util.concurrent.CompletableFuture; import java.util.concurrent.ConcurrentHashMap; /** * Netty client. * * @author <a href="http://github.com/kuujo">Jordan Halterman</a> */ public class NettyClient implements Client { private static final Logger LOGGER = LoggerFactory.getLogger(NettyClient.class); private static final ByteBufAllocator ALLOCATOR = new PooledByteBufAllocator(true); private static final ChannelHandler FIELD_PREPENDER = new LengthFieldPrepender(4); private final NettyTransport transport; private final Map<Channel, NettyConnection> connections = new ConcurrentHashMap<>(); /** * @throws NullPointerException if {@code id} or {@code eventLoopGroup} are null */ public NettyClient(NettyTransport transport) { this.transport = Assert.notNull(transport, "transport"); } @Override public CompletableFuture<Connection> connect(Address address) { Assert.notNull(address, "address"); ThreadContext context = ThreadContext.currentContextOrThrow(); CompletableFuture<Connection> future = new ComposableFuture<>(); LOGGER.info("Connecting to {}", address); Bootstrap bootstrap = new Bootstrap(); bootstrap.group(transport.eventLoopGroup()).channel(NioSocketChannel.class) .handler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(SocketChannel channel) throws Exception { ChannelPipeline pipeline = channel.pipeline(); if (transport.properties().sslEnabled()) { pipeline.addFirst( new SslHandler(new NettyTls(transport.properties()).initSslEngine(true))); } pipeline.addLast(FIELD_PREPENDER); pipeline.addLast(new LengthFieldBasedFrameDecoder(transport.properties().maxFrameSize(), 0, 4, 0, 4)); pipeline.addLast( new NettyHandler(connections, future::complete, context, transport.properties())); } }); bootstrap.option(ChannelOption.TCP_NODELAY, transport.properties().tcpNoDelay()); bootstrap.option(ChannelOption.SO_KEEPALIVE, transport.properties().tcpKeepAlive()); bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, transport.properties().connectTimeout()); bootstrap.option(ChannelOption.ALLOCATOR, ALLOCATOR); if (transport.properties().sendBufferSize() != -1) { bootstrap.option(ChannelOption.SO_SNDBUF, transport.properties().sendBufferSize()); } if (transport.properties().receiveBufferSize() != -1) { bootstrap.option(ChannelOption.SO_RCVBUF, transport.properties().receiveBufferSize()); } bootstrap.connect(address.socketAddress()).addListener(channelFuture -> { if (channelFuture.isSuccess()) { LOGGER.info("Connected to {}", address); } else { context.execute(() -> future.completeExceptionally(channelFuture.cause())); } }); return future; } @Override public CompletableFuture<Void> close() { ThreadContext.currentContextOrThrow(); int i = 0; CompletableFuture<?>[] futures = new CompletableFuture[connections.size()]; for (Connection connection : connections.values()) { futures[i++] = connection.close(); } return CompletableFuture.allOf(futures); } }