129 lines
4.3 KiB
HTML
129 lines
4.3 KiB
HTML
<html>
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<head>
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<title>Smack: Chat - Jive Software</title>
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<link rel="stylesheet" type="text/css" href="style.css"/>
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</head>
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<body>
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<div class="header">
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Messaging using Chats
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</div>
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<div class="nav">
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« <a href="index.html">Table of Contents</a>
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</div>
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<p>
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Sending messages back and forth is at the core of instant messaging. Although individual
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messages
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can be sent and received as packets, it's generally easier to treat the string of messages
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as a chat using the <tt>org.jivesoftware.smack.Chat</tt> class.
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</p>
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<p class="subheader">
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Chat
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</p>
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A chat creates a new thread of messages (using a thread ID) between two users. The
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following code snippet demonstrates how to create a new Chat with a user and then send
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them a text message:<p>
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<div class="code"><pre><font color="gray"><i>// Assume we've created a XMPPConnection name "connection".</i></font>
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ChatManager chatmanager = connection.getChatManager();
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Chat newChat = chatmanager.createChat(<font
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color="green">"jsmith@jivesoftware.com"</font>, new MessageListener() {
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public void processMessage(Chat chat, Message message) {
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System.out.println(<font color="green">"Received message: "</font> + message);
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}
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});
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try {
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newChat.sendMessage(<font color="green">"Howdy!"</font>);
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}
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catch (XMPPException e) {
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System.out.println(<font color="green">"Error Delivering block"</font>);
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}
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</pre>
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</div>
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<p>
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The <tt>Chat.sendMessage(String)</tt> method is a convenience method that creates a Message
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object, sets the body using the String parameter, then sends the message. In the case
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that you wish to set additional values on a Message before sending it, use the
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<tt>Chat.createMessage()</tt> and <tt>Chat.sendMessage(Message)</tt> methods, as in the
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following code snippet:
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<p>
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<div class="code"><pre>
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Message newMessage = new Message();
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newMessage.setBody(<font color="green">"Howdy!"</font>);
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message.setProperty(<font color="green">"favoriteColor"</font>, <font color="green">"red"</font>);
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newChat.sendMessage(newMessage);
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</pre>
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</div>
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<p>
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You'll also notice in the example above that we specified a MessageListener when creating a
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chat.
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The listener is notified any time a new message arrives from the other user in the chat.
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The following code snippet uses the listener as a parrot-bot -- it echoes back everything the
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other user types.
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<p>
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<div class="code"><pre>
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<font color="gray"><i> // Assume a MessageListener we've setup with a chat.</i></font>
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public void processMessage(Chat chat, Message message) {
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<font color="gray"><i>// Send back the same text the other user sent us.</i></font>
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chat.sendMessage(message.getBody());
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}
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</pre>
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</div>
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<p class="subheader">
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Incoming Chat
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</p>
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When chats are prompted by another user, the setup is slightly different since
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you are receiving a chat message first. Instead of explicitly creating a chat to send
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messages, you need to register to handle newly created Chat instances when the ChatManager
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creates them.
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</br>
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</br>
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The ChatManager will already find a matching chat (by thread id) and if none exists, then it
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will create a new one that does match. To get this new chat, you have to register to be
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notified when it happens. You can register a message listener to receive all future messages as
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part of this handler.<p>
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<div class="code"><pre><font color="gray"><i>// Assume we've created a XMPPConnection name "connection".</i></font>
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ChatManager chatmanager = connection.getChatManager().addChatListener(
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new ChatManagerListener() {
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@Override
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public void chatCreated(Chat chat, boolean createdLocally)
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{
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if (!createdLocally)
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chat.addMessageListener(new MyNewMessageListener());;
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}
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});
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</pre>
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</div>
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In addition to thread based chat messages, there are some clients that
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do not send a thread id as part of the chat. To handle this scenario,
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Smack will attempt match the incoming messages to the best fit existing
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chat, based on the JID. It will attempt to find a chat with the same full
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JID, failing that, it will try the base JID. If no existing chat to the
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user can found, then a new one is created.
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<p>
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<br clear="all"/><br><br>
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<div class="footer">
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Copyright © Jive Software 2002-2008
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</div>
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</body>
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</html>
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