Java tutorial
/** * $RCSfile$ * $Revision: 1701 $ * $Date: 2005-07-26 02:23:45 -0300 (Tue, 26 Jul 2005) $ * * Copyright (C) 2005-2008 B5Chat Community. 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.b5chat.crossfire.xmpp.disco; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.locks.Lock; import org.b5chat.crossfire.core.util.cache.Cache; import org.b5chat.crossfire.core.util.cache.CacheFactory; import org.b5chat.crossfire.xmpp.handler.IQHandler; import org.b5chat.crossfire.xmpp.handler.IQHandlerInfo; import org.b5chat.crossfire.xmpp.roster.RosterItem; import org.b5chat.crossfire.xmpp.server.XmppServer; import org.b5chat.crossfire.xmpp.session.ISession; import org.b5chat.crossfire.xmpp.session.SessionManager; import org.b5chat.crossfire.xmpp.user.IUserItemsProvider; import org.b5chat.crossfire.xmpp.user.User; import org.b5chat.crossfire.xmpp.user.UserManager; import org.b5chat.crossfire.xmpp.user.UserNotFoundException; import org.dom4j.DocumentHelper; import org.dom4j.Element; import org.dom4j.QName; import org.xmpp.packet.IQ; import org.xmpp.packet.JID; import org.xmpp.packet.PacketError; import org.xmpp.resultsetmanagement.ResultSet; import org.xmpp.resultsetmanagement.ResultSetImpl; /** * IQDiscoItemsHandler is responsible for handling disco#items requests. This class holds a map with * the main entities and the associated IDiscoItemsProvider. We are considering the host of the * recipient JIDs as main entities. It's the IDiscoItemsProvider responsibility to provide the items * associated with the JID's name together with any possible requested node.<p> * <p/> * For example, let's have in the entities map the following entries: "localhost" and * "conference.localhost". Associated with each entry we have different IDiscoItemsProvider. Now we * receive a disco#items request for the following JID: "room@conference.localhost" which is a disco * request for a MUC room. So IQDiscoItemsHandler will look for the IDiscoItemsProvider associated * with the JID's host which in this case is "conference.localhost". Once we have located the * provider we will delegate to the provider the responsibility to provide the items specific to * the JID's name which in this case is "room". Depending on the implementation, the items could be * the list of existing occupants if that information is publicly available. Finally, after we have * collected all the items provided by the provider we will add them to the reply. On the other * hand, if no provider was found or the provider has no information for the requested name/node * then a not-found error will be returned.<p> * <p/> * Publishing of client items is still not supported. * * @author Gaston Dombiak */ public class IQDiscoItemsHandler extends IQHandler implements IServerFeaturesProvider, IUserItemsProvider { public static final String NAMESPACE_DISCO_ITEMS = "http://jabber.org/protocol/disco#items"; private Map<String, IDiscoItemsProvider> entities = new HashMap<String, IDiscoItemsProvider>(); private Map<String, Element> localServerItems = new HashMap<String, Element>(); private Cache<String, Element> serverItems; private Map<String, IDiscoItemsProvider> serverNodeProviders = new ConcurrentHashMap<String, IDiscoItemsProvider>(); private IQHandlerInfo info; private IQDiscoInfoHandler infoHandler; public IQDiscoItemsHandler() { super("XMPP Disco Items Handler"); info = new IQHandlerInfo("query", NAMESPACE_DISCO_ITEMS); } @Override public IQHandlerInfo getInfo() { return info; } @Override public IQ handleIQ(IQ packet) { // Create a copy of the sent pack that will be used as the reply // we only need to add the requested items to the reply if any otherwise add // a not found error IQ reply = IQ.createResultIQ(packet); // TODO Implement publishing client items if (IQ.Type.set == packet.getType()) { reply.setChildElement(packet.getChildElement().createCopy()); reply.setError(PacketError.Condition.feature_not_implemented); return reply; } // Look for a IDiscoItemsProvider associated with the requested entity. // We consider the host of the recipient JID of the packet as the entity. It's the // IDiscoItemsProvider responsibility to provide the items associated with the JID's name // together with any possible requested node. IDiscoItemsProvider itemsProvider = getProvider( packet.getTo() == null ? XmppServer.getInstance().getServerInfo().getXMPPDomain() : packet.getTo().getDomain()); if (itemsProvider != null) { // Get the JID's name String name = packet.getTo() == null ? null : packet.getTo().getNode(); if (name == null || name.trim().length() == 0) { name = null; } // Get the requested node Element iq = packet.getChildElement(); String node = iq.attributeValue("node"); // Check if we have items associated with the requested name and node Iterator<DiscoItem> itemsItr = itemsProvider.getItems(name, node, packet.getFrom()); if (itemsItr != null) { reply.setChildElement(iq.createCopy()); Element queryElement = reply.getChildElement(); // See if the requesting entity would like to apply 'result set // management' final Element rsmElement = packet.getChildElement() .element(QName.get("set", ResultSet.NAMESPACE_RESULT_SET_MANAGEMENT)); // apply RSM only if the element exists, and the (total) results // set is not empty. final boolean applyRSM = rsmElement != null && itemsItr.hasNext(); if (applyRSM) { if (!ResultSet.isValidRSMRequest(rsmElement)) { reply.setError(PacketError.Condition.bad_request); return reply; } // Calculate which results to include. final List<DiscoItem> rsmResults; final List<DiscoItem> allItems = new ArrayList<DiscoItem>(); while (itemsItr.hasNext()) { allItems.add(itemsItr.next()); } final ResultSet<DiscoItem> rs = new ResultSetImpl<DiscoItem>(allItems); try { rsmResults = rs.applyRSMDirectives(rsmElement); } catch (NullPointerException e) { final IQ itemNotFound = IQ.createResultIQ(packet); itemNotFound.setError(PacketError.Condition.item_not_found); return itemNotFound; } // add the applicable results to the IQ-result for (DiscoItem item : rsmResults) { final Element resultElement = item.getElement(); resultElement.setQName(new QName(resultElement.getName(), queryElement.getNamespace())); queryElement.add(resultElement.createCopy()); } // overwrite the 'set' element. queryElement.remove( queryElement.element(QName.get("set", ResultSet.NAMESPACE_RESULT_SET_MANAGEMENT))); queryElement.add(rs.generateSetElementFromResults(rsmResults)); } else { // don't apply RSM: // Add to the reply all the items provided by the IDiscoItemsProvider Element item; while (itemsItr.hasNext()) { item = itemsItr.next().getElement(); item.setQName(new QName(item.getName(), queryElement.getNamespace())); queryElement.add(item.createCopy()); } } } else { // If the IDiscoItemsProvider has no items for the requested name and node // then answer a not found error reply.setChildElement(packet.getChildElement().createCopy()); reply.setError(PacketError.Condition.item_not_found); } } else { // If we didn't find a IDiscoItemsProvider then answer a not found error reply.setChildElement(packet.getChildElement().createCopy()); reply.setError(PacketError.Condition.item_not_found); } return reply; } /** * Returns the IDiscoItemsProvider responsible for providing the items related to a given entity * or null if none was found. * * @param name the name of the identity. * @return the IDiscoItemsProvider responsible for providing the items related to a given entity * or null if none was found. */ private IDiscoItemsProvider getProvider(String name) { return entities.get(name); } /** * Sets that a given IDiscoItemsProvider will provide the items related to a given entity. This * message must be used when new modules (e.g. MUC) are implemented and need to provide * the items related to them. * * @param name the name of the entity. * @param provider the IDiscoItemsProvider that will provide the entity's items. */ protected void setProvider(String name, IDiscoItemsProvider provider) { entities.put(name, provider); } /** * Removes the IDiscoItemsProvider related to a given entity. * * @param name the name of the entity. */ protected void removeProvider(String name) { entities.remove(name); } /** * Adds the items provided by the new service that implements the IServerItemsProvider * interface. This information will be used whenever a disco for items is made against * the server (i.e. the packet's target is the server). * Example of item is: <item jid='conference.localhost' name='Public chatrooms'/> * * @param provider the IServerItemsProvider that provides new server items. */ public void addServerItemsProvider(IServerItemsProvider provider) { DiscoServerItem discoItem; Iterator<DiscoServerItem> items = provider.getItems(); if (items == null) { // Do nothing return; } while (items.hasNext()) { discoItem = items.next(); // Add the element to the list of items related to the server addComponentItem(discoItem.getJID().toString(), discoItem.getNode(), discoItem.getName()); // Add the new item as a valid entity that could receive info and items disco requests String host = discoItem.getJID().getDomain(); infoHandler.setProvider(host, discoItem.getDiscoInfoProvider()); setProvider(host, discoItem.getDiscoItemsProvider()); } } /** * Removes the provided items as a service of the service. * * @param provider The provider that is being removed. */ public void removeServerItemsProvider(IServerItemsProvider provider) { DiscoServerItem discoItem; Iterator<DiscoServerItem> items = provider.getItems(); if (items == null) { // Do nothing return; } while (items.hasNext()) { discoItem = items.next(); // Remove the item from the server items list removeComponentItem(discoItem.getJID().toString()); // Remove the item as a valid entity that could receive info and items disco requests String host = discoItem.getJID().getDomain(); infoHandler.removeProvider(host); removeProvider(host); } } /** * Sets the IDiscoItemsProvider to use when a disco#items packet is sent to the server itself * and the specified node. For instance, if node matches "http://jabber.org/protocol/offline" * then a special IDiscoItemsProvider should be use to return information about offline messages. * * @param node the node that the provider will handle. * @param provider the IDiscoItemsProvider that will handle disco#items packets sent with the * specified node. */ public void setServerNodeInfoProvider(String node, IDiscoItemsProvider provider) { serverNodeProviders.put(node, provider); } /** * Removes the IDiscoItemsProvider to use when a disco#items packet is sent to the server itself * and the specified node. * * @param node the node that the provider was handling. */ public void removeServerNodeInfoProvider(String node) { serverNodeProviders.remove(node); } /** * Registers a new disco item for a component. The jid attribute of the item will match the jid * of the component and the name should be the name of the component discovered using disco. * * @param jid the jid of the component. * @param name the discovered name of the component. */ public void addComponentItem(String jid, String name) { addComponentItem(jid, null, name); } /** * Registers a new disco item for a component. The jid attribute of the item will match the jid * of the component and the name should be the name of the component discovered using disco. * * @param jid the jid of the component. * @param node the node that complements the jid address. * @param name the discovered name of the component. */ public void addComponentItem(String jid, String node, String name) { Lock lock = CacheFactory.getLock(jid, serverItems); try { lock.lock(); Element item = serverItems.get(jid); if (item == null) { // First time a node registers a server item for this component item = DocumentHelper.createElement("item"); item.addAttribute("jid", jid); item.addAttribute("node", node); item.addAttribute("name", name); } // Update the cache with latest info serverItems.put(jid, item); // Keep track of the new server item added by this JVM localServerItems.put(jid, item); } finally { lock.unlock(); } } /** * Removes a disco item for a component that has been removed from the server. * * @param jid the jid of the component being removed. */ public void removeComponentItem(String jid) { if (serverItems == null) { // Safety check return; } Lock lock = CacheFactory.getLock(jid, serverItems); try { lock.lock(); Element item = serverItems.get(jid); if (item != null) { // Update the cache with latest info serverItems.remove(jid); } } finally { lock.unlock(); } // Remove locally added server item localServerItems.remove(jid); } @Override public void initialize(XmppServer server) { super.initialize(server); serverItems = CacheFactory.createCache("Disco Server Items"); // Track the implementors of IServerItemsProvider so that we can collect the items // provided by the server infoHandler = server.getIQDiscoInfoHandler(); setProvider(server.getServerInfo().getXMPPDomain(), getServerItemsProvider()); // Listen to cluster events } @Override public void start() throws IllegalStateException { super.start(); for (IServerItemsProvider provider : XmppServer.getInstance().getServerItemsProviders()) { addServerItemsProvider(provider); } } public Iterator<String> getFeatures() { List<String> features = new ArrayList<String>(); features.add("http://jabber.org/protocol/disco#items"); // TODO Comment out this line when publishing of client items is implemented //features.add("http://jabber.org/protocol/disco#publish"); return features.iterator(); } private IDiscoItemsProvider getServerItemsProvider() { return new IDiscoItemsProvider() { public Iterator<DiscoItem> getItems(String name, String node, JID senderJID) { if (node != null) { // Check if there is a provider for the requested node if (serverNodeProviders.get(node) != null) { return serverNodeProviders.get(node).getItems(name, node, senderJID); } return null; } if (name == null) { List<DiscoItem> answer = new ArrayList<DiscoItem>(); for (Element item : serverItems.values()) { answer.add(new DiscoItem(item)); } return answer.iterator(); } else { // If addressed to user@domain, add items from UserItemsProviders to // the reply. List<IUserItemsProvider> itemsProviders = XmppServer.getInstance().getUserItemsProviders(); if (itemsProviders.isEmpty()) { // If we didn't find any UserItemsProviders, then answer a not found error return null; } List<DiscoItem> answer = new ArrayList<DiscoItem>(); for (IUserItemsProvider itemsProvider : itemsProviders) { // Check if we have items associated with the requested name Iterator<Element> itemsItr = itemsProvider.getUserItems(name, senderJID); if (itemsItr != null) { // Add to the reply all the items provided by the IUserItemsProvider Element item; while (itemsItr.hasNext()) { item = itemsItr.next(); JID itemJid = new JID(item.attributeValue("jid")); String itemName = item.attributeValue("name"); String itemNode = item.attributeValue("node"); String itemAction = item.attributeValue("action"); answer.add(new DiscoItem(itemJid, itemName, itemNode, itemAction)); } } } return answer.iterator(); } } }; } public Iterator<Element> getUserItems(String name, JID senderJID) { List<Element> answer = new ArrayList<Element>(); try { User user = UserManager.getInstance().getUser(name); RosterItem item = user.getRoster().getRosterItem(senderJID); // If the requesting entity is subscribed to the account's presence then // answer the user's "available resources" if (item.getSubStatus() == RosterItem.SUB_FROM || item.getSubStatus() == RosterItem.SUB_BOTH) { for (ISession session : SessionManager.getInstance().getSessions(name)) { Element element = DocumentHelper.createElement("item"); element.addAttribute("jid", session.getAddress().toString()); answer.add(element); } } return answer.iterator(); } catch (UserNotFoundException e) { return answer.iterator(); } } }