Smack/documentation/gettingstarted.html

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<title>Smack: Getting Started - Jive Software</title>
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<div class="header">
Getting Started With Smack
</div>
<div class="nav">
&laquo; <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>
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<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 &copy; Jive Software 2002-2003
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