<html> <head> <title>Smack: Getting Started - Jive Software</title> <link rel="stylesheet" type="text/css" href="style.css" / </head> <body> <div class="header"> Getting Started With Smack </div> <div class="nav"> « <a href="index.html">Table of Contents</a> </div> <p> This document will introduce you to the Smack API and provide an overview of important classes and concepts. </p> <p class="subheader"> Requirements </p> The only requirement for Smack is JDK 1.2 or later<sup> <a style="text-decoration:none;" href="#ssenote">1</a></sup>. An XML parser is embedded in the smack.jar file and no other third party libraries are required.<p> <sup>1</sup> <font size="-1"><i>JDK 1.2 and 1.3 users that wish to use SSL connections must have the <a href="http://java.sun.com/products/jsse/index-103.html">JSSE</a> library in their classpath.</i></font> <p class="subheader"> Establishing a Connection </p> The <tt>XMPPConnection</tt> class is used to create a connection to an XMPP server. To create an SSL connection, use the SSLXMPPConnection class. Below are code examples for making a connection:<p> <div class="code"> <pre> <font color="gray"><i>// Create a connection to the jabber.org server.</i></font> XMPPConnection conn1 = <font color="navy"><b>new</b></font> XMPPConnection(<font color="green">"jabber.org"</font>); <font color="gray"><i>// Create a connection to the jabber.org server on a specific port.</i></font> XMPPConnection conn2 = <font color="navy"><b>new</b></font> XMPPConnection(<font color="green">"jabber.org"</font>, 5222); <font color="gray"><i>// Create an SSL connection to jabber.org.</i></font> XMPPConnection connection = <font color="navy"><b>new</b></font> SSLXMPPConnection(<font color="green">"jabber.org"</font>); </pre></div> <p>Once you've created a connection, you should login using a username and password with the <tt>XMPPConnection.login(String username, String password)</tt> method. Once you've logged in, you can being chatting with other users by creating new <tt>Chat</tt> or <tt>GroupChat</tt> objects. <p class="subheader"> Working with the Roster </p> The roster lets you keep track of the availability (presence) of other users. Users can be organized into groups such as "Friends" and "Co-workers", and then you discover whether each user is online or offline.<p> Retrieve the roster using the <tt>XMPPConnection.getRoster()</tt> method. The roster class allows you to find all the roster entries, the groups they belong to, and the current presence status of each entry. <p class="subheader"> Reading and Writing Packets </p> Each message to the XMPP server from a client is called a packet and is sent as XML. The <tt>org.jivesoftware.smack.packet</tt> package contains classes that encapsulate the three different basic packet types allowed by XMPP (message, presence, and IQ). Classes such as <tt>Chat</tt> and <tt>GroupChat</tt> provide higher-level constructs that manage creating and sending packets automatically, but you can also create and send packets directly. Below is a code example for changing your presence to let people know you're unavailable and "out fishing":<p> <div class="code"> <pre> <font color="gray"><i>// Create a new presence. Pass in false to indicate we're unavailable.</i></font> Presence presence = new Presence(Presence.Type.UNAVAILABLE); presence.setStatus(<font color="green">"Gone fishing"</font>); <font color="gray"><i>// Send the packet (assume we have a XMPPConnection instance called "con").</i></font> con.sendPacket(presence); </pre></div> <p> Smack provides two ways to read incoming packets: <tt>PacketListener</tt>, and <tt>PacketCollector</tt>. Both use <tt>PacketFilter</tt> instances to determine which packets should be processed. A packet listener is used for event style programming, while a packet collector has a result queue of packets that you can do polling and blocking operations on. So, a packet listener is useful when you want to take some action whenever a packet happens to come in, while a packet collector is useful when you want to wait for a specific packet to arrive. Packet collectors and listeners can be created using an XMPPConnection instance. <p><div class="footer"> Copyright © Jive Software 2002-2004 </div> </body> </html>