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| <title>Send Messages to Remote Endpoint</title><link rel="stylesheet" type="text/css" href="css/docbook.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><meta name="keywords" content="jetty, servlet, servlet-api, cometd, http, websocket, eclipse, maven, java, server, software"><link rel="home" href="index.html" title="Jetty"><link rel="up" href="websocket-jetty.html" title="Chapter 27. Jetty Websocket API"><link rel="prev" href="jetty-websocket-api-session.html" title="WebSocket Session"><link rel="next" href="jetty-websocket-api-annotations.html" title="Using WebSocket Annotations"><link xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" rel="shortcut icon" href="images/favicon.ico"><link rel="stylesheet" href="css/highlighter/foundation.css"><script src="js/highlight.pack.js"></script><script> |
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| Version: 9.4.28-SNAPSHOT</span></td><td style="width: 50%"></td></tr></table><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Send Messages to Remote Endpoint</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="jetty-websocket-api-session.html"><i class="fa fa-chevron-left" aria-hidden="true"></i> Previous</a> </td><th width="60%" align="center">Chapter 27. Jetty Websocket API<br><a accesskey="p" href="index.html"><i class="fa fa-home" aria-hidden="true"></i> Home</a></th><td width="20%" align="right"> <a accesskey="n" href="jetty-websocket-api-annotations.html">Next <i class="fa fa-chevron-right" aria-hidden="true"></i></a></td></tr></table><hr></div><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="jetty-callout"><h5 class="callout"><a href="http://www.webtide.com/">Contact the core Jetty developers at |
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| </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="jetty-websocket-api-send-message"></a>Send Messages to Remote Endpoint</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="section"><a href="jetty-websocket-api-send-message.html#blocking">Blocking Send Message</a></span></dt><dt><span class="section"><a href="jetty-websocket-api-send-message.html#partial">Send Partial Message</a></span></dt><dt><span class="section"><a href="jetty-websocket-api-send-message.html#pingpong">Send Ping / Pong Control Frame</a></span></dt><dt><span class="section"><a href="jetty-websocket-api-send-message.html#async">Async Send Message</a></span></dt></dl></div><p>The most important feature of the Session is access to the <a class="link" href="http://www.eclipse.org/jetty/javadoc/9.4.28-SNAPSHOT/org/eclipse/jetty/websocket/api/RemoteEndpoint.html" target="_top"><code class="literal">org.eclipse.jetty.websocket.api.RemoteEndpoint</code></a> needed to send messages.</p><p>With RemoteEndpoint you can choose to send TEXT or BINARY WebSocket messages, or the WebSocket PING and PONG control frames.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="blocking"></a>Blocking Send Message</h3></div></div></div><p>Most calls are blocking in nature, and will not return until the send has completed (or has thrown an exception).</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Blocking Send of a BINARY message to remote endpoint |
| ByteBuffer buf = ByteBuffer.wrap(new byte[] { 0x11, 0x22, 0x33, 0x44 }); |
| try |
| { |
| remote.sendBytes(buf); |
| } |
| catch (IOException e) |
| { |
| e.printStackTrace(System.err); |
| }</code></pre><p>How to send a simple Binary message using the RemoteEndpoint. |
| This will block until the message is sent, possibly throwing an IOException if unable to send the message.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Blocking Send of a TEXT message to remote endpoint |
| try |
| { |
| remote.sendString("Hello World"); |
| } |
| catch (IOException e) |
| { |
| e.printStackTrace(System.err); |
| }</code></pre><p>How to send a simple Text message using the RemoteEndpoint. |
| This will block until the message is sent, possibly throwing an IOException if unable to send the message.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="partial"></a>Send Partial Message</h3></div></div></div><p>If you have a large message to send, and want to send it in pieces and parts, you can utilize the partial message sending methods of RemoteEndpoint. |
| Just be sure you finish sending your message (<code class="literal">isLast == true</code>).</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Blocking Send of a BINARY message to remote endpoint |
| // Part 1 |
| ByteBuffer buf1 = ByteBuffer.wrap(new byte[] { 0x11, 0x22 }); |
| // Part 2 (last part) |
| ByteBuffer buf2 = ByteBuffer.wrap(new byte[] { 0x33, 0x44 }); |
| try |
| { |
| remote.sendPartialBytes(buf1,false); |
| remote.sendPartialBytes(buf2,true); // isLast is true |
| } |
| catch (IOException e) |
| { |
| e.printStackTrace(System.err); |
| }</code></pre><p>How to send a Binary message in 2 parts, using the partial message support in RemoteEndpoint. |
| This will block until each part of the message is sent, possibly throwing an IOException if unable to send the partial message.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Blocking Send of a TEXT message to remote endpoint |
| String part1 = "Hello"; |
| String part2 = " World"; |
| try |
| { |
| remote.sendPartialString(part1,false); |
| remote.sendPartialString(part2,true); // last part |
| } |
| catch (IOException e) |
| { |
| e.printStackTrace(System.err); |
| }</code></pre><p>How to send a Text message in 2 parts, using the partial message support in RemoteEndpoint. |
| This will block until each part of the message is sent, possibly throwing an IOException if unable to send the partial message.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="pingpong"></a>Send Ping / Pong Control Frame</h3></div></div></div><p>You can also send Ping and Pong control frames using the RemoteEndpoint.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Blocking Send of a PING to remote endpoint |
| String data = "You There?"; |
| ByteBuffer payload = ByteBuffer.wrap(data.getBytes()); |
| try |
| { |
| remote.sendPing(payload); |
| } |
| catch (IOException e) |
| { |
| e.printStackTrace(System.err); |
| }</code></pre><p>How to send a Ping control frame, with a payload of <code class="literal">"You There?"</code> (arriving at Remote Endpoint as a byte array payload). |
| This will block until the message is sent, possibly throwing an IOException if unable to send the ping frame.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Blocking Send of a PONG to remote endpoint |
| String data = "Yup, I'm here"; |
| ByteBuffer payload = ByteBuffer.wrap(data.getBytes()); |
| try |
| { |
| remote.sendPong(payload); |
| } |
| catch (IOException e) |
| { |
| e.printStackTrace(System.err); |
| }</code></pre><p>How to send a Pong control frame, with a payload of <code class="literal">"Yup I'm here"</code> (arriving at Remote Endpoint as a byte array payload). |
| This will block until the message is sent, possibly throwing an IOException if unable to send the pong frame.</p><p>To be correct in your usage of Pong frames, you should return the same byte array data that you received in the Ping frame.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="async"></a>Async Send Message</h3></div></div></div><p>However there are also 2 Async send message methods available:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><a class="link" href="http://www.eclipse.org/jetty/javadoc/9.4.28-SNAPSHOT/org/eclipse/jetty/websocket/api/RemoteEndpoint.html#sendBytesByFuture(java.nio.ByteBuffer)" target="_top"><code class="literal">RemoteEndpoint.sendBytesByFuture(ByteBuffer message)</code></a></li><li class="listitem"><a class="link" href="http://www.eclipse.org/jetty/javadoc/9.4.28-SNAPSHOT/org/eclipse/jetty/websocket/api/RemoteEndpoint.html#sendStringByFuture(java.lang.String)" target="_top"><code class="literal">RemoteEndpoint.sendStringByFuture(String message)</code></a></li></ul></div><p>Both return a <code class="literal">Future<Void></code> that can be used to test for success and failure of the message send using standard <a class="link" href="http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/Future.html" target="_top"><code class="literal">java.util.concurrent.Future</code></a> behavior.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Async Send of a BINARY message to remote endpoint |
| ByteBuffer buf = ByteBuffer.wrap(new byte[] { 0x11, 0x22, 0x33, 0x44 }); |
| remote.sendBytesByFuture(buf);</code></pre><p>How to send a simple Binary message using the RemoteEndpoint. |
| The message will be enqueued for outgoing write, but you will not know if it succeeded or failed.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Async Send of a BINARY message to remote endpoint |
| ByteBuffer buf = ByteBuffer.wrap(new byte[] { 0x11, 0x22, 0x33, 0x44 }); |
| try |
| { |
| Future<Void> fut = remote.sendBytesByFuture(buf); |
| // wait for completion (forever) |
| fut.get(); |
| } |
| catch (ExecutionException | InterruptedException e) |
| { |
| // Send failed |
| e.printStackTrace(); |
| }</code></pre><p>How to send a simple Binary message using the RemoteEndpoint, tracking the <code class="literal">Future<Void></code> to know if the send succeeded or failed.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Async Send of a BINARY message to remote endpoint |
| ByteBuffer buf = ByteBuffer.wrap(new byte[] { 0x11, 0x22, 0x33, 0x44 }); |
| Future<Void> fut = null; |
| try |
| { |
| fut = remote.sendBytesByFuture(buf); |
| // wait for completion (timeout) |
| fut.get(2,TimeUnit.SECONDS); |
| } |
| catch (ExecutionException | InterruptedException e) |
| { |
| // Send failed |
| e.printStackTrace(); |
| } |
| catch (TimeoutException e) |
| { |
| // timeout |
| e.printStackTrace(); |
| if (fut != null) |
| { |
| // cancel the message |
| fut.cancel(true); |
| } |
| }</code></pre><p>How to send a simple Binary message using the RemoteEndpoint, tracking the <code class="literal">Future<Void></code> and waiting only prescribed amount of time for the send to complete, cancelling the message if the timeout occurs.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Async Send of a TEXT message to remote endpoint |
| remote.sendStringByFuture("Hello World");</code></pre><p>How to send a simple Text message using the RemoteEndpoint. |
| The message will be enqueued for outgoing write, but you will not know if it succeeded or failed.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Async Send of a TEXT message to remote endpoint |
| try |
| { |
| Future<Void> fut = remote.sendStringByFuture("Hello World"); |
| // wait for completion (forever) |
| fut.get(); |
| } |
| catch (ExecutionException | InterruptedException e) |
| { |
| // Send failed |
| e.printStackTrace(); |
| }</code></pre><p>How to send a simple Binary message using the RemoteEndpoint, tracking the <code class="literal">Future<Void></code> to know if the send succeeded or failed.</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>RemoteEndpoint remote = session.getRemote(); |
| |
| // Async Send of a TEXT message to remote endpoint |
| Future<Void> fut = null; |
| try |
| { |
| fut = remote.sendStringByFuture("Hello World"); |
| // wait for completion (timeout) |
| fut.get(2,TimeUnit.SECONDS); |
| } |
| catch (ExecutionException | InterruptedException e) |
| { |
| // Send failed |
| e.printStackTrace(); |
| } |
| catch (TimeoutException e) |
| { |
| // timeout |
| e.printStackTrace(); |
| if (fut != null) |
| { |
| // cancel the message |
| fut.cancel(true); |
| } |
| }</code></pre><p>How to send a simple Binary message using the RemoteEndpoint, tracking the <code class="literal">Future<Void></code> and waiting only prescribed amount of time for the send to complete, cancelling the message if the timeout occurs.</p></div></div><script type="text/javascript"> |
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