0cb4cc4e49
Motivation: We wish to separate these two into clearer write/read interfaces. In particular, we don't want to be able to add listeners to promises, because it makes it easy to add them out of order. We can't prevent it entirely, because any promise can be freely converted to a future where listeners can be added. We can, however, discourage this in the API. Modification: The Promise interface no longer extends the Future interface. Numerous changes to make the project compile and its tests run. Result: Clearer separation of concerns in the code.
91 lines
3.4 KiB
Java
91 lines
3.4 KiB
Java
/*
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* Copyright 2020 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License, version 2.0 (the
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* "License"); you may not use this file except in compliance with the License. You may obtain a
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* copy of the License at:
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software distributed under the License
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* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
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* or implied. See the License for the specific language governing permissions and limitations under
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* the License.
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*/
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package io.netty.example.smtp;
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import io.netty.buffer.ByteBuf;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.SimpleChannelInboundHandler;
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import io.netty.handler.codec.smtp.DefaultLastSmtpContent;
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import io.netty.handler.codec.smtp.SmtpRequest;
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import io.netty.handler.codec.smtp.SmtpResponse;
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import io.netty.util.concurrent.EventExecutor;
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import io.netty.util.concurrent.FutureCompletionStage;
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import io.netty.util.concurrent.Promise;
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import java.util.concurrent.atomic.AtomicReference;
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/**
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* An example smtp client handler
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*/
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public class SmtpClientHandler extends SimpleChannelInboundHandler<SmtpResponse> {
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private ChannelHandlerContext ctx;
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private final AtomicReference<Promise<SmtpResponse>> responseFuture = new AtomicReference<>();
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@Override
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public void channelActive(ChannelHandlerContext ctx) throws Exception {
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this.ctx = ctx;
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}
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@Override
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protected void messageReceived(ChannelHandlerContext ctx, SmtpResponse response) throws Exception {
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Promise<SmtpResponse> promise = responseFuture.get();
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if (promise == null) {
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throw new RuntimeException("Unexpected response received: " + response);
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} else {
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if (response.code() >= 500) {
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throw new RuntimeException("receive an error: " + response);
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}
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printResponse(response);
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promise.setSuccess(response);
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responseFuture.set(null);
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}
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}
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private static void printResponse(SmtpResponse response) {
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System.out.println(response);
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}
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@Override
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public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
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cause.printStackTrace();
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responseFuture.get().setFailure(cause);
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ctx.close();
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}
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public FutureCompletionStage<SmtpResponse> send(SmtpRequest request) {
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FutureCompletionStage<SmtpResponse> future = createResponseFuture(ctx.executor());
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ctx.writeAndFlush(request);
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return future;
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}
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public FutureCompletionStage<SmtpResponse> sendMailContent(ByteBuf content) {
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FutureCompletionStage<SmtpResponse> future = createResponseFuture(ctx.executor());
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ctx.writeAndFlush(new DefaultLastSmtpContent(content));
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return future;
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}
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public FutureCompletionStage<SmtpResponse> createResponseFuture(EventExecutor executor) {
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Promise<SmtpResponse> promise = executor.newPromise();
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while (!responseFuture.compareAndSet(null, promise)) {
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Promise<SmtpResponse> previousFuture = responseFuture.get();
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if (previousFuture != null) {
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throw new RuntimeException("Still waiting for the past response");
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}
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}
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return promise.asFuture().asStage();
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}
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}
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