mirror of
https://github.com/vanitasvitae/Smack.git
synced 2024-11-25 21:42:07 +01:00
f155cb4d07
Separated the reading of provider files from the ProviderManager. Manager now only manages. Added ability to add collections of providers to the manager via a ProviderLoader, of which there is one default implementation which loads from the default file format. Now provider files can be programmatically added at any time. Also updated the configuration abilities so that a provider file can also be set via VM arg, as well as the smack configuration itself. Introduced Java Util Logging as well. git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/branches/smack_3_4_0@13861 b35dd754-fafc-0310-a699-88a17e54d16e
282 lines
11 KiB
HTML
282 lines
11 KiB
HTML
<html>
|
|
<head>
|
|
<title>Smack: Provider Architecture - Jive Software</title>
|
|
<link rel="stylesheet" type="text/css" href="style.css" />
|
|
</head>
|
|
|
|
<body>
|
|
|
|
<div class="header">
|
|
Provider Architecture: Packet Extensions and Custom IQ's
|
|
</div>
|
|
|
|
<div class="nav">
|
|
« <a href="index.html">Table of Contents</a>
|
|
</div>
|
|
|
|
<p>
|
|
<p class="subheader">Introduction</p>
|
|
|
|
The Smack provider architecture is a system for plugging in
|
|
custom XML parsing of packet extensions and IQ packets. The
|
|
standard <a href="extensions/index.html">Smack Extensions</a>
|
|
are built using the provider architecture. There are two types of
|
|
providers:<ul>
|
|
<li><tt>IQProvider</tt> -- parses IQ requests into Java objects.
|
|
<li><tt>Extension Provider</tt> -- parses XML sub-documents attached to
|
|
packets into PacketExtension instances.</ul>
|
|
|
|
By default, Smack only knows how to process a few standard packets and sub-packets
|
|
that are in a few namespaces such as:<ul>
|
|
<li>jabber:iq:auth
|
|
<li>jabber:iq:roster
|
|
<li>jabber:iq:register</ul>
|
|
|
|
There are many more IQ types and extensions that are part of XMPP standards, and of
|
|
course an endless number that can be added as custom extensions. To support this, an
|
|
extensible parsing mechanism is provided via Smack and user build providers.
|
|
<p>
|
|
Whenever a packet extension is found in a packet, parsing will
|
|
be passed to the correct provider. Each provider can either implement the
|
|
PacketExtensionProvider interface or be a standard Java Bean. In the
|
|
former case, each extension provider is responsible for parsing the raw
|
|
XML stream, via the <a href="http://www.xmlpull.org/">XML Pull Parser</a>, to contruct an object. In the latter case, bean introspection
|
|
is used to try to automatically set the properties of the class using
|
|
the values in the packet extension sub-element.
|
|
<p>
|
|
When no extension provider is registered for an element name and
|
|
namespace combination, Smack will store all top-level elements of the
|
|
sub-packet in the DefaultPacketExtension object and then attach it to the packet.
|
|
|
|
<p>
|
|
Management of these providers is accomplished via the <a href="">ProviderManager</a>
|
|
class. There are multiple ways to add providers to the manager.<ul>
|
|
<li>Call addXXProvider methods - You can call the appropriate add methods directly.
|
|
<pre>
|
|
ProviderManager.getInstance().addIQProvider("element", "namespace", new MyIQProvider());
|
|
ProviderManager.getInstance().addExtensionProvider("element", "namespace", new MyExtProvider());
|
|
</pre>
|
|
<li>Add a loader - You can add a ProviderLoader which will inject a means of loading multiple
|
|
providers (both types) into the manager. This is the mechanism used by Smack to load from the
|
|
Smack specific file format (via ProviderFileLoader). Implementers can provide the means to load
|
|
providers from any source they wish, or simply reuse the ProviderFileLoader to load from
|
|
their own provider files.
|
|
<pre>
|
|
ProviderManager.getInstance().addLoader(new ProviderFileLoader(FileUtils.getStreamForUrl("classpath:com/myco/provider/myco_custom.providers", null)));
|
|
</pre>
|
|
<li>VM Argument - You can add a provider file via the VM argument <i>smack.provider.file</i>.
|
|
This will load the file at the specified URL during startup when Smack initializes.
|
|
This also assumes the default configuration, since it requires that the <b>VmArgInitializer</b> was
|
|
part of the startup configuration.
|
|
|
|
<pre>
|
|
-Dsmack.provider.file=classpath:com/myco/provider/myco_custom.providers
|
|
or
|
|
-Dsmack.provider.file=file:///c:/myco/provider/myco_custom.providers
|
|
</pre>
|
|
</ul>
|
|
|
|
<p class="subheader">IQ Providers</p>
|
|
|
|
The IQ provider class can either implement the IQProvider
|
|
interface, or extend the IQ class. In the former case, each IQProvider is
|
|
responsible for parsing the raw XML stream to create an IQ instance. In
|
|
the latter case, bean introspection is used to try to automatically set
|
|
properties of the IQ instance using the values found in the IQ packet XML.
|
|
For example, an XMPP time packet resembles the following:
|
|
|
|
<p>
|
|
<i>Introspection</i>
|
|
<p>
|
|
<u>Time Packet</u>
|
|
<pre>
|
|
<iq type='result' to='joe@example.com' from='mary@example.com' id='time_1'>
|
|
<query xmlns='jabber:iq:time'>
|
|
<utc>20020910T17:58:35</utc>
|
|
<tz>MDT</tz>
|
|
<display>Tue Sep 10 12:58:35 2002</display>
|
|
</query>
|
|
</iq>
|
|
</pre>
|
|
|
|
<p>
|
|
<u>Time IQ Class</u>
|
|
<pre>
|
|
class Time extends IQ {
|
|
private Date utc;
|
|
private TimeZone timeZone;
|
|
private String display;
|
|
|
|
@Override
|
|
public String getChildElementXML() {
|
|
return null;
|
|
}
|
|
|
|
public void setUtc(String utcString) {
|
|
try {
|
|
utc = StringUtils.parseDate(utcString);
|
|
} catch (ParseException e) {
|
|
}
|
|
}
|
|
|
|
public void setTimeZone(String zone) {
|
|
timeZone = TimeZone.getTimeZone(zone);
|
|
}
|
|
|
|
public void setDisplay(String timeDisplay) {
|
|
display = timeDisplay;
|
|
}
|
|
}
|
|
</pre>
|
|
|
|
The introspection service will automatically try to convert the String
|
|
value from the XML into a boolean, int, long, float, double, or Class depending on the
|
|
type the IQ instance expects.
|
|
|
|
<p>
|
|
<i>IQProvider Implementation</i>
|
|
<p>
|
|
<u>Disco Items Packet</u>
|
|
<pre>
|
|
<iq type='result' from='shakespeare.lit' to='romeo@montague.net/orchard' id='items1'>
|
|
<query xmlns='http://jabber.org/protocol/disco#items'>
|
|
<item jid='people.shakespeare.lit' name='Directory of Characters'/>
|
|
<item jid='plays.shakespeare.lit' name='Play-Specific Chatrooms'/>
|
|
<item jid='mim.shakespeare.lit' name='Gateway to Marlowe IM'/>
|
|
<item jid='words.shakespeare.lit' name='Shakespearean Lexicon'/>
|
|
<item jid='globe.shakespeare.lit' name='Calendar of Performances'/>
|
|
<item jid='headlines.shakespeare.lit' name='Latest Shakespearean News'/>
|
|
<item jid='catalog.shakespeare.lit' name='Buy Shakespeare Stuff!'/>
|
|
<item jid='en2fr.shakespeare.lit' name='French Translation Service'/>
|
|
</query>
|
|
</iq>
|
|
</pre>
|
|
|
|
<p>
|
|
<u>Disco Items IQProvider</u>
|
|
<pre>
|
|
public class DiscoverItemsProvider implements IQProvider {
|
|
|
|
public IQ parseIQ(XmlPullParser parser) throws Exception {
|
|
DiscoverItems discoverItems = new DiscoverItems();
|
|
boolean done = false;
|
|
DiscoverItems.Item item;
|
|
String jid = "";
|
|
String name = "";
|
|
String action = "";
|
|
String node = "";
|
|
discoverItems.setNode(parser.getAttributeValue("", "node"));
|
|
while (!done) {
|
|
int eventType = parser.next();
|
|
|
|
if (eventType == XmlPullParser.START_TAG && "item".equals(parser.getName())) {
|
|
// Initialize the variables from the parsed XML
|
|
jid = parser.getAttributeValue("", "jid");
|
|
name = parser.getAttributeValue("", "name");
|
|
node = parser.getAttributeValue("", "node");
|
|
action = parser.getAttributeValue("", "action");
|
|
}
|
|
else if (eventType == XmlPullParser.END_TAG && "item".equals(parser.getName())) {
|
|
// Create a new Item and add it to DiscoverItems.
|
|
item = new DiscoverItems.Item(jid);
|
|
item.setName(name);
|
|
item.setNode(node);
|
|
item.setAction(action);
|
|
discoverItems.addItem(item);
|
|
}
|
|
else if (eventType == XmlPullParser.END_TAG && "query".equals(parser.getName())) {
|
|
done = true;
|
|
}
|
|
}
|
|
return discoverItems;
|
|
}
|
|
}
|
|
</pre>
|
|
|
|
<p class="subheader">Extension Providers</p>
|
|
|
|
Packet extension providers are responsible for parsing packet extensions, which are
|
|
child elements in a custom namespace of IQ, message and presence packets.
|
|
<p>
|
|
<u>Pubsub Subscription Packet</u>
|
|
|
|
<pre>
|
|
<iq type='result' from='pubsub.shakespeare.lit' to='francisco@denmark.lit/barracks' id='sub1'>
|
|
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
|
|
<subscription node='princely_musings' jid='francisco@denmark.lit' subscription='unconfigured'>
|
|
<subscribe-options>
|
|
<required/>
|
|
</subscribe-options>
|
|
</subscription>
|
|
</pubsub>
|
|
</iq>
|
|
</pre>
|
|
|
|
<p>
|
|
<u>Subscription PacketExtensionProvider Implementation</u>
|
|
|
|
<pre>
|
|
public class SubscriptionProvider implements PacketExtensionProvider {
|
|
public PacketExtension parseExtension(XmlPullParser parser) throws Exception {
|
|
String jid = parser.getAttributeValue(null, "jid");
|
|
String nodeId = parser.getAttributeValue(null, "node");
|
|
String subId = parser.getAttributeValue(null, "subid");
|
|
String state = parser.getAttributeValue(null, "subscription");
|
|
boolean isRequired = false;
|
|
|
|
int tag = parser.next();
|
|
|
|
if ((tag == XmlPullParser.START_TAG) && parser.getName().equals("subscribe-options")) {
|
|
tag = parser.next();
|
|
|
|
if ((tag == XmlPullParser.START_TAG) && parser.getName().equals("required"))
|
|
isRequired = true;
|
|
|
|
while (parser.next() != XmlPullParser.END_TAG && parser.getName() != "subscribe-options");
|
|
}
|
|
while (parser.getEventType() != XmlPullParser.END_TAG) parser.next();
|
|
return new Subscription(jid, nodeId, subId, (state == null ? null : Subscription.State.valueOf(state)), isRequired);
|
|
}
|
|
}
|
|
</pre>
|
|
|
|
<p class="subheader">Provider file format</p>
|
|
|
|
This is the format for a provider file which can be parsed by the <b>ProviderFileLoader</b>.
|
|
<pre>
|
|
<?xml version="1.0"?>
|
|
<smackProviders>
|
|
<iqProvider>
|
|
<elementName>query</elementName>
|
|
<namespace>jabber:iq:time</namespace>
|
|
<className>org.jivesoftware.smack.packet.Time</className>
|
|
</iqProvider>
|
|
|
|
<iqProvider>
|
|
<elementName>query</elementName>
|
|
<namespace>http://jabber.org/protocol/disco#items</namespace>
|
|
<className>org.jivesoftware.smackx.provider.DiscoverItemsProvider</className>
|
|
</iqProvider>
|
|
|
|
<extensionProvider>
|
|
<elementName>subscription</elementName>
|
|
<namespace>http://jabber.org/protocol/pubsub</namespace>
|
|
<className>org.jivesoftware.smackx.pubsub.provider.SubscriptionProvider</className>
|
|
</extensionProvider>
|
|
</smackProviders></pre>
|
|
|
|
Each provider is associated with an element name and a namespace. If multiple provider entries attempt to register to
|
|
handle the same namespace, the last entry added to the <b>ProviderManager</b> will overwrite any other that was loaded
|
|
before it.
|
|
<p>
|
|
|
|
|
|
|
|
<br clear="all" /><br><br>
|
|
|
|
<div class="footer">
|
|
Copyright © Jive Software 2002-2008
|
|
</div>
|
|
|
|
</body>
|
|
</html>
|