| /* |
| * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package jdk.incubator.http.internal.websocket; |
| |
| import java.io.IOException; |
| import java.nio.channels.SelectionKey; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| import java.util.function.Consumer; |
| |
| import static java.util.Objects.requireNonNull; |
| |
| /* |
| * Sends messages one at a time, in an asynchronous and non-blocking fashion. |
| * |
| * No matter whether the message has been fully sent or an error has occurred, |
| * the transmitter reports the outcome to the supplied handler and becomes ready |
| * to accept a new message. Until then, the transmitter is considered "busy" and |
| * an IllegalStateException will be thrown on each attempt to invoke send. |
| */ |
| final class Transmitter { |
| |
| /* This flag is used solely for assertions */ |
| private final AtomicBoolean busy = new AtomicBoolean(); |
| private OutgoingMessage message; |
| private Consumer<Exception> completionHandler; |
| private final RawChannel channel; |
| private final RawChannel.RawEvent event; |
| |
| Transmitter(RawChannel channel) { |
| this.channel = requireNonNull(channel); |
| this.event = createHandler(); |
| } |
| |
| /** |
| * The supplied handler may be invoked in the calling thread. |
| * A {@code StackOverflowError} may thus occur if there's a possibility |
| * that this method is called again by the supplied handler. |
| */ |
| void send(OutgoingMessage message, Consumer<Exception> completionHandler) { |
| requireNonNull(message); |
| requireNonNull(completionHandler); |
| if (!busy.compareAndSet(false, true)) { |
| throw new IllegalStateException(); |
| } |
| send0(message, completionHandler); |
| } |
| |
| private RawChannel.RawEvent createHandler() { |
| return new RawChannel.RawEvent() { |
| |
| @Override |
| public int interestOps() { |
| return SelectionKey.OP_WRITE; |
| } |
| |
| @Override |
| public void handle() { |
| // registerEvent(e) happens-before subsequent e.handle(), so |
| // we're fine reading the stored message and the completionHandler |
| send0(message, completionHandler); |
| } |
| }; |
| } |
| |
| private void send0(OutgoingMessage message, Consumer<Exception> handler) { |
| boolean b = busy.get(); |
| assert b; // Please don't inline this, as busy.get() has memory |
| // visibility effects and we don't want the program behaviour |
| // to depend on whether the assertions are turned on |
| // or turned off |
| try { |
| boolean sent = message.sendTo(channel); |
| if (sent) { |
| busy.set(false); |
| handler.accept(null); |
| } else { |
| // The message has not been fully sent, the transmitter needs to |
| // remember the message until it can continue with sending it |
| this.message = message; |
| this.completionHandler = handler; |
| try { |
| channel.registerEvent(event); |
| } catch (IOException e) { |
| this.message = null; |
| this.completionHandler = null; |
| busy.set(false); |
| handler.accept(e); |
| } |
| } |
| } catch (IOException e) { |
| busy.set(false); |
| handler.accept(e); |
| } |
| } |
| } |