Smack

org.jivesoftware.smack.provider
Class ProviderManager

java.lang.Object
  extended by org.jivesoftware.smack.provider.ProviderManager

public class ProviderManager
extends Object

Manages providers for parsing custom XML sub-documents of XMPP packets. Two types of providers exist:

IQProvider

By default, Smack only knows how to process IQ packets with sub-packets that are in a few namespaces such as:

Because many more IQ types are part of XMPP and its extensions, a pluggable IQ parsing mechanism is provided. IQ providers are registered programatically or by creating a smack.providers file in the META-INF directory of your JAR file. The file is an XML document that contains one or more iqProvider entries, as in the following example:
 <?xml version="1.0"?>
 <smackProviders>
     <iqProvider>
         <elementName>query</elementName>
         <namespace>jabber:iq:time</namespace>
         <className>org.jivesoftware.smack.packet.Time</className>
     </iqProvider>
 </smackProviders>
Each IQ provider is associated with an element name and a namespace. If multiple provider entries attempt to register to handle the same namespace, the first entry loaded from the classpath will take precedence. 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:
 <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>
In order for this packet to be automatically mapped to the Time object listed in the providers file above, it must have the methods setUtc(String), setTz(String), and setDisplay(String). 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.

A pluggable system for packet extensions, child elements in a custom namespace for message and presence packets, also exists. Each extension provider is registered with a name space in the smack.providers file as in the following example:

 <?xml version="1.0"?>
 <smackProviders>
     <extensionProvider>
         <elementName>x</elementName>
         <namespace>jabber:iq:event</namespace>
         <className>org.jivesoftware.smack.packet.MessageEvent</className>
     </extensionProvider>
 </smackProviders>
If multiple provider entries attempt to register to handle the same element name and namespace, the first entry loaded from the classpath will take precedence. 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 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. When an extension provider is not registered for an element name and namespace combination, Smack will store all top-level elements of the sub-packet in DefaultPacketExtension object and then attach it to the packet.

Author:
Matt Tucker

Method Summary
static void addExtensionProvider(String elementName, String namespace, Object provider)
          Adds an extension provider with the specified element name and name space.
static void addIQProvider(String elementName, String namespace, Object provider)
          Adds an IQ provider (must be an instance of IQProvider or Class object that is an IQ) with the specified element name and name space.
static Object getExtensionProvider(String elementName, String namespace)
          Returns the packet extension provider registered to the specified XML element name and namespace.
static Iterator getExtensionProviders()
          Returns an Iterator for all PacketExtensionProvider instances.
static Object getIQProvider(String elementName, String namespace)
          Returns the IQ provider registered to the specified XML element name and namespace.
static Iterator getIQProviders()
          Returns an Iterator for all IQProvider instances.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

getIQProvider

public static Object getIQProvider(String elementName,
                                   String namespace)
Returns the IQ provider registered to the specified XML element name and namespace. For example, if a provider was registered to the element name "query" and the namespace "jabber:iq:time", then the following packet would trigger the provider:
 <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>

Note: this method is generally only called by the internal Smack classes.

Parameters:
elementName - the XML element name.
namespace - the XML namespace.
Returns:
the IQ provider.

getIQProviders

public static Iterator getIQProviders()
Returns an Iterator for all IQProvider instances.

Returns:
an Iterator for all IQProvider instances.

addIQProvider

public static void addIQProvider(String elementName,
                                 String namespace,
                                 Object provider)
Adds an IQ provider (must be an instance of IQProvider or Class object that is an IQ) with the specified element name and name space. The provider will override any providers loaded through the classpath.

Parameters:
elementName - the XML element name.
namespace - the XML namespace.
provider - the IQ provider.

getExtensionProvider

public static Object getExtensionProvider(String elementName,
                                          String namespace)
Returns the packet extension provider registered to the specified XML element name and namespace. For example, if a provider was registered to the element name "x" and the namespace "jabber:x:event", then the following packet would trigger the provider:
 <message to='romeo@montague.net' id='message_1'>
     <body>Art thou not Romeo, and a Montague?</body>
     <x xmlns='jabber:x:event'>
         <composing/>
     </x>
 </message>

Note: this method is generally only called by the internal Smack classes.

Parameters:
elementName -
namespace -
Returns:
the extenion provider.

addExtensionProvider

public static void addExtensionProvider(String elementName,
                                        String namespace,
                                        Object provider)
Adds an extension provider with the specified element name and name space. The provider will override any providers loaded through the classpath. The provider must be either a PacketExtensionProvider instance, or a Class object of a Javabean.

Parameters:
elementName - the XML element name.
namespace - the XML namespace.
provider - the extension provider.

getExtensionProviders

public static Iterator getExtensionProviders()
Returns an Iterator for all PacketExtensionProvider instances.

Returns:
an Iterator for all PacketExtensionProvider instances.

Smack

Copyright © 2003 Jive Software.