/**
* $RCSfile$
* $Revision: 4538 $
* $Date: 2006-07-18 09:14:33 +0400 (Tue, 18 Jul 2006) $
*
* Copyright 2003-2004 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;
import org.jivesoftware.smack.filter.PacketFilter;
import org.jivesoftware.smack.filter.ThreadFilter;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.util.StringUtils;
import java.lang.ref.WeakReference;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
/**
* A chat is a series of messages sent between two users. Each chat has a unique
* thread ID, which is used to track which messages are part of a particular
* conversation. Some messages are sent without a thread ID, and some clients
* don't send thread IDs at all. Therefore, if a message without a thread ID
* arrives it is routed to the most recently created Chat with the message
* sender.
*
* @see XMPPConnection#createChat(String)
* @author Matt Tucker
*/
public class Chat {
/**
* A prefix helps to make sure that ID's are unique across mutliple instances.
*/
private static String prefix = StringUtils.randomString(5);
/**
* Keeps track of the current increment, which is appended to the prefix to
* forum a unique ID.
*/
private static long id = 0;
/**
* Returns the next unique id. Each id made up of a short alphanumeric
* prefix along with a unique numeric value.
*
* @return the next id.
*/
private static synchronized String nextID() {
return prefix + Long.toString(id++);
}
private XMPPConnection connection;
private String threadID;
private String participant;
private PacketFilter messageFilter;
private PacketCollector messageCollector;
private final Set<WeakReference<PacketListener>> listeners =
new HashSet<WeakReference<PacketListener>>();
/**
* Creates a new chat with the specified user.
*
* @param connection the connection the chat will use.
* @param participant the user to chat with.
*/
public Chat(XMPPConnection connection, String participant) {
// Automatically assign the next chat ID.
this(connection, participant, nextID());
}
/**
* Creates a new chat with the specified user and thread ID.
*
* @param connection the connection the chat will use.
* @param participant the user to chat with.
* @param threadID the thread ID to use.
*/
public Chat(XMPPConnection connection, String participant, String threadID) {
this.connection = connection;
this.participant = participant;
this.threadID = threadID;
// Register with the map of chats so that messages with no thread ID
// set will be delivered to this Chat.
connection.chats.put(StringUtils.parseBareAddress(participant),
new WeakReference<Chat>(this));
// Filter the messages whose thread equals Chat's id
messageFilter = new ThreadFilter(threadID);
messageCollector = connection.createPacketCollector(messageFilter);
}
/**
* Returns the thread id associated with this chat, which corresponds to the
* <tt>thread</tt> field of XMPP messages. This method may return <tt>null</tt>
* if there is no thread ID is associated with this Chat.
*
* @return the thread ID of this chat.
*/
public String getThreadID() {
return threadID;
}
/**
* Returns the name of the user the chat is with.
*
* @return the name of the user the chat is occuring with.
*/
public String getParticipant() {
return participant;
}
/**
* Sends the specified text as a message to the other chat participant.
* This is a convenience method for:
*
* <pre>
* Message message = chat.createMessage();
* message.setBody(messageText);
* chat.sendMessage(message);
* </pre>
*
* @param text the text to send.
* @throws XMPPException if sending the message fails.
*/
public void sendMessage(String text) throws XMPPException {
Message message = createMessage();
message.setBody(text);
connection.sendPacket(message);
}
/**
* Creates a new Message to the chat participant. The message returned
* will have its thread property set with this chat ID.
*
* @return a new message addressed to the chat participant and
* using the correct thread value.
* @see #sendMessage(Message)
*/
public Message createMessage() {
Message message = new Message(participant, Message.Type.CHAT);
message.setThread(threadID);
return message;
}
/**
* Sends a message to the other chat participant. The thread ID, recipient,
* and message type of the message will automatically set to those of this chat
* in case the Message was not created using the {@link #createMessage() createMessage}
* method.
*
* @param message the message to send.
* @throws XMPPException if an error occurs sending the message.
*/
public void sendMessage(Message message) throws XMPPException {
// Force the recipient, message type, and thread ID since the user elected
// to send the message through this chat object.
message.setTo(participant);
message.setType(Message.Type.CHAT);
message.setThread(threadID);
connection.sendPacket(message);
}
/**
* Polls for and returns the next message, or <tt>null</tt> if there isn't
* a message immediately available. This method provides significantly different
* functionalty than the {@link #nextMessage()} method since it's non-blocking.
* In other words, the method call will always return immediately, whereas the
* nextMessage method will return only when a message is available (or after
* a specific timeout).
*
* @return the next message if one is immediately available and
* <tt>null</tt> otherwise.
*/
public Message pollMessage() {
return (Message)messageCollector.pollResult();
}
/**
* Returns the next available message in the chat. The method call will block
* (not return) until a message is available.
*
* @return the next message.
*/
public Message nextMessage() {
return (Message)messageCollector.nextResult();
}
/**
* Returns the next available message in the chat. The method call will block
* (not return) until a packet is available or the <tt>timeout</tt> has elapased.
* If the timeout elapses without a result, <tt>null</tt> will be returned.
*
* @param timeout the maximum amount of time to wait for the next message.
* @return the next message, or <tt>null</tt> if the timeout elapses without a
* message becoming available.
*/
public Message nextMessage(long timeout) {
return (Message)messageCollector.nextResult(timeout);
}
/**
* Adds a packet listener that will be notified of any new messages in the
* chat.
*
* @param listener a packet listener.
*/
public void addMessageListener(PacketListener listener) {
connection.addPacketListener(listener, messageFilter);
// Keep track of the listener so that we can manually deliver extra
// messages to it later if needed.
synchronized (listeners) {
listeners.add(new WeakReference<PacketListener>(listener));
}
}
/**
* Delivers a message directly to this chat, which will add the message
* to the collector and deliver it to all listeners registered with the
* Chat. This is used by the XMPPConnection class to deliver messages
* without a thread ID.
*
* @param message the message.
*/
void deliver(Message message) {
// Because the collector and listeners are expecting a thread ID with
// a specific value, set the thread ID on the message even though it
// probably never had one.
message.setThread(threadID);
messageCollector.processPacket(message);
synchronized (listeners) {
for (Iterator<WeakReference<PacketListener>> i=listeners.iterator(); i.hasNext(); ) {
WeakReference<PacketListener> listenerRef = i.next();
PacketListener listener;
if ((listener = listenerRef.get()) != null) {
listener.processPacket(message);
}
// If the reference was cleared, remove it from the set.
else {
i.remove();
}
}
}
}
public void finalize() throws Throwable {
super.finalize();
try {
if (messageCollector != null) {
messageCollector.cancel();
}
}
catch (Exception e) {
// Ignore.
}
}
}