/**
* $RCSfile$
* $Revision: 13325 $
* $Date: 2012-10-26 03:47:55 -0700 (Fri, 26 Oct 2012) $
*
* Copyright 2003-2007 Jive Software.
*
* All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jivesoftware.smack.provider;
import org.jivesoftware.smack.packet.IQ;
import org.jivesoftware.smack.packet.PacketExtension;
import org.xmlpull.mxp1.MXParser;
import org.xmlpull.v1.XmlPullParser;
import java.io.InputStream;
import java.net.URL;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
/**
* Manages providers for parsing custom XML sub-documents of XMPP packets. Two types of
* providers exist:<ul>
* <li>IQProvider -- parses IQ requests into Java objects.
* <li>PacketExtension -- parses XML sub-documents attached to packets into
* PacketExtension instances.</ul>
*
* <b>IQProvider</b><p>
*
* By default, Smack only knows how to process IQ packets with sub-packets that
* are in a few namespaces such as:<ul>
* <li>jabber:iq:auth
* <li>jabber:iq:roster
* <li>jabber:iq:register</ul>
*
* 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:
*
* <pre>
* <?xml version="1.0"?>
* <smackProviders>
* <iqProvider>
* <elementName>query</elementName>
* <namespace>jabber:iq:time</namespace>
* <className>org.jivesoftware.smack.packet.Time</className>
* </iqProvider>
* </smackProviders></pre>
*
* 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:
* <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>
*
* 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.<p>
*
* 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:
*
* <pre>
* <?xml version="1.0"?>
* <smackProviders>
* <extensionProvider>
* <elementName>x</elementName>
* <namespace>jabber:iq:event</namespace>
* <className>org.jivesoftware.smack.packet.MessageEvent</className>
* </extensionProvider>
* </smackProviders></pre>
*
* 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.<p>
*
* It is possible to provide a custom provider manager instead of the default implementation
* provided by Smack. If you want to provide your own provider manager then you need to do it
* before creating any {@link org.jivesoftware.smack.Connection} by sending the static
* {@link #setInstance(ProviderManager)} message. Trying to change the provider manager after
* an Connection was created will result in an {@link IllegalStateException} error.
*
* @author Matt Tucker
*/
public class ProviderManager {
private static ProviderManager instance;
private Map<String, Object> extensionProviders = new ConcurrentHashMap<String, Object>();
private Map<String, Object> iqProviders = new ConcurrentHashMap<String, Object>();
/**
* Returns the only ProviderManager valid instance. Use {@link #setInstance(ProviderManager)}
* to configure your own provider manager. If non was provided then an instance of this
* class will be used.
*
* @return the only ProviderManager valid instance.
*/
public static synchronized ProviderManager getInstance() {
if (instance == null) {
instance = new ProviderManager();
}
return instance;
}
/**
* Sets the only ProviderManager valid instance to be used by all Connections. If you
* want to provide your own provider manager then you need to do it before creating
* any Connection. Otherwise an IllegalStateException will be thrown.
*
* @param providerManager the only ProviderManager valid instance to be used.
* @throws IllegalStateException if a provider manager was already configued.
*/
public static synchronized void setInstance(ProviderManager providerManager) {
if (instance != null) {
throw new IllegalStateException("ProviderManager singleton already set");
}
instance = providerManager;
}
protected void initialize() {
// Load IQ processing providers.
try {
// Get an array of class loaders to try loading the providers files from.
ClassLoader[] classLoaders = getClassLoaders();
for (ClassLoader classLoader : classLoaders) {
Enumeration<URL> providerEnum = classLoader.getResources(
"META-INF/smack.providers");
while (providerEnum.hasMoreElements()) {
URL url = providerEnum.nextElement();
InputStream providerStream = null;
try {
providerStream = url.openStream();
XmlPullParser parser = new MXParser();
parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
parser.setInput(providerStream, "UTF-8");
int eventType = parser.getEventType();
do {
if (eventType == XmlPullParser.START_TAG) {
if (parser.getName().equals("iqProvider")) {
parser.next();
parser.next();
String elementName = parser.nextText();
parser.next();
parser.next();
String namespace = parser.nextText();
parser.next();
parser.next();
String className = parser.nextText();
// Only add the provider for the namespace if one isn't
// already registered.
String key = getProviderKey(elementName, namespace);
if (!iqProviders.containsKey(key)) {
// Attempt to load the provider class and then create
// a new instance if it's an IQProvider. Otherwise, if it's
// an IQ class, add the class object itself, then we'll use
// reflection later to create instances of the class.
try {
// Add the provider to the map.
Class<?> provider = Class.forName(className);
if (IQProvider.class.isAssignableFrom(provider)) {
iqProviders.put(key, provider.newInstance());
}
else if (IQ.class.isAssignableFrom(provider)) {
iqProviders.put(key, provider);
}
}
catch (ClassNotFoundException cnfe) {
cnfe.printStackTrace();
}
}
}
else if (parser.getName().equals("extensionProvider")) {
parser.next();
parser.next();
String elementName = parser.nextText();
parser.next();
parser.next();
String namespace = parser.nextText();
parser.next();
parser.next();
String className = parser.nextText();
// Only add the provider for the namespace if one isn't
// already registered.
String key = getProviderKey(elementName, namespace);
if (!extensionProviders.containsKey(key)) {
// Attempt to load the provider class and then create
// a new instance if it's a Provider. Otherwise, if it's
// a PacketExtension, add the class object itself and
// then we'll use reflection later to create instances
// of the class.
try {
// Add the provider to the map.
Class<?> provider = Class.forName(className);
if (PacketExtensionProvider.class.isAssignableFrom(
provider)) {
extensionProviders.put(key, provider.newInstance());
}
else if (PacketExtension.class.isAssignableFrom(
provider)) {
extensionProviders.put(key, provider);
}
}
catch (ClassNotFoundException cnfe) {
cnfe.printStackTrace();
}
}
}
}
eventType = parser.next();
}
while (eventType != XmlPullParser.END_DOCUMENT);
}
finally {
try {
providerStream.close();
}
catch (Exception e) {
// Ignore.
}
}
}
}
}
catch (Exception e) {
e.printStackTrace();
}
}
/**
* 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:
*
* <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>Note: this method is generally only called by the internal Smack classes.
*
* @param elementName the XML element name.
* @param namespace the XML namespace.
* @return the IQ provider.
*/
public Object getIQProvider(String elementName, String namespace) {
String key = getProviderKey(elementName, namespace);
return iqProviders.get(key);
}
/**
* Returns an unmodifiable collection of all IQProvider instances. Each object
* in the collection will either be an IQProvider instance, or a Class object
* that implements the IQProvider interface.
*
* @return all IQProvider instances.
*/
public Collection<Object> getIQProviders() {
return Collections.unmodifiableCollection(iqProviders.values());
}
/**
* 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.
*
* @param elementName the XML element name.
* @param namespace the XML namespace.
* @param provider the IQ provider.
*/
public void addIQProvider(String elementName, String namespace,
Object provider)
{
if (!(provider instanceof IQProvider || (provider instanceof Class &&
IQ.class.isAssignableFrom((Class<?>)provider))))
{
throw new IllegalArgumentException("Provider must be an IQProvider " +
"or a Class instance.");
}
String key = getProviderKey(elementName, namespace);
iqProviders.put(key, provider);
}
/**
* Removes an IQ provider with the specified element name and namespace. This
* method is typically called to cleanup providers that are programatically added
* using the {@link #addIQProvider(String, String, Object) addIQProvider} method.
*
* @param elementName the XML element name.
* @param namespace the XML namespace.
*/
public void removeIQProvider(String elementName, String namespace) {
String key = getProviderKey(elementName, namespace);
iqProviders.remove(key);
}
/**
* 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:
*
* <pre>
* <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></pre>
*
* <p>Note: this method is generally only called by the internal Smack classes.
*
* @param elementName element name associated with extension provider.
* @param namespace namespace associated with extension provider.
* @return the extenion provider.
*/
public Object getExtensionProvider(String elementName, String namespace) {
String key = getProviderKey(elementName, namespace);
return extensionProviders.get(key);
}
/**
* 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.
*
* @param elementName the XML element name.
* @param namespace the XML namespace.
* @param provider the extension provider.
*/
public void addExtensionProvider(String elementName, String namespace,
Object provider)
{
if (!(provider instanceof PacketExtensionProvider || provider instanceof Class)) {
throw new IllegalArgumentException("Provider must be a PacketExtensionProvider " +
"or a Class instance.");
}
String key = getProviderKey(elementName, namespace);
extensionProviders.put(key, provider);
}
/**
* Removes an extension provider with the specified element name and namespace. This
* method is typically called to cleanup providers that are programatically added
* using the {@link #addExtensionProvider(String, String, Object) addExtensionProvider} method.
*
* @param elementName the XML element name.
* @param namespace the XML namespace.
*/
public void removeExtensionProvider(String elementName, String namespace) {
String key = getProviderKey(elementName, namespace);
extensionProviders.remove(key);
}
/**
* Returns an unmodifiable collection of all PacketExtensionProvider instances. Each object
* in the collection will either be a PacketExtensionProvider instance, or a Class object
* that implements the PacketExtensionProvider interface.
*
* @return all PacketExtensionProvider instances.
*/
public Collection<Object> getExtensionProviders() {
return Collections.unmodifiableCollection(extensionProviders.values());
}
/**
* Returns a String key for a given element name and namespace.
*
* @param elementName the element name.
* @param namespace the namespace.
* @return a unique key for the element name and namespace pair.
*/
private String getProviderKey(String elementName, String namespace) {
StringBuilder buf = new StringBuilder();
buf.append("<").append(elementName).append("/><").append(namespace).append("/>");
return buf.toString();
}
/**
* Returns an array of class loaders to load resources from.
*
* @return an array of ClassLoader instances.
*/
private ClassLoader[] getClassLoaders() {
ClassLoader[] classLoaders = new ClassLoader[2];
classLoaders[0] = ProviderManager.class.getClassLoader();
classLoaders[1] = Thread.currentThread().getContextClassLoader();
// Clean up possible null values. Note that #getClassLoader may return a null value.
List<ClassLoader> loaders = new ArrayList<ClassLoader>();
for (ClassLoader classLoader : classLoaders) {
if (classLoader != null) {
loaders.add(classLoader);
}
}
return loaders.toArray(new ClassLoader[loaders.size()]);
}
private ProviderManager() {
super();
initialize();
}
}