Smack/documentation/extensions/filetransfer.html

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<div class="header">File Transfer</div><p>
The file transfer extension allows the user to transmit and receive files.
<ul>
<li><a href="#sendfile">Send a file to another user</a></li>
<li><a href="#recievefile">Recieving a file from another user</a></li>
<li><a href="#monitorprogress">Monitoring the progress of a file transfer</a></li>
</ul>
<b>XEP related:</b> <a href="http://www.xmpp.org/extensions/xep-0095.html">XEP-95</a>
<a href="http://www.xmpp.org/extensions/xep-0096.html">XEP-96</a>
<a href="http://www.xmpp.org/extensions/xep-0065.html">XEP-65</a>
<a href="http://www.xmpp.org/extensions/xep-0047.html">XEP-47</a>
<hr>
<div class="subheader"><a name="sendfile">Send a file to another user</a></div><p>
<b>Description</b><p>
A user may wish to send a file to another user. The other user has the option of acception,
rejecting, or ignoring the users request. Smack provides a simple interface in order
to enable the user to easily send a file.
<b>Usage</b><p>
In order to send a file you must first construct an instance of the <b><i>FileTransferManager</i></b>
class. This class has one constructor with one parameter which is your XMPPConnection.
In order to instantiate the manager you should call <i>new FileTransferManager(connection)</i>
<p>Once you have your <b><i>FileTransferManager</i></b> you will need to create an outgoing
file transfer to send a file. The method to use on the <b><i>FileTransferManager</i></b>
is the <b>createOutgoingFileTransfer(userID)</b> method. The userID you provide to this
method is the fully-qualified jabber ID of the user you wish to send the file to. A
fully-qualified jabber ID consists of a node, a domain, and a resource, the user
must be connected to the resource in order to be able to recieve the file transfer.
<p>Now that you have your <b><i>OutgoingFileTransfer</i></b> instance you will want
to send the file. The method to send a file is <b>sendFile(file, description)</b>. The file
you provide to this method should be a readable file on the local file system, and the description is a short
description of the file to help the user decide whether or not they would like to recieve the file.
<p>For information on monitoring the progress of a file transfer see the <a href="#monitorprogress">monitoring progress</a>
section of this document.
<p>Other means to send a file are also provided as part of the <b><i>OutgoingFileTransfer</i></b>. Please
consult the Javadoc for more information.
<b>Examples</b><p>
In this example we can see how to send a file: <br>
<blockquote>
<pre>
<font color="#3f7f5f">// Create the file transfer manager</font>
FileTransferManager manager = new FileTransferManager(connection);
<font color="#3f7f5f">// Create the outgoing file transfer</font>
OutgoingFileTransfer transfer = manager.createOutgoingFileTransfer(<font color="#0000FF">"romeo@montague.net"</font>);
<font color="#3f7f5f">// Send the file</font>
transfer.sendFile(new File(<font color="#0000FF">"shakespeare_complete_works.txt"</font>), <font color="#0000FF">"You won't believe this!"</font>);
</pre>
</blockquote>
<hr>
<div class="subheader"><a name="recievefile">Recieving a file from another user</a></div><p>
<b>Description</b><p>
The user may wish to recieve files from another user. The process of recieving a file is event driven,
new file transfer requests are recieved from other users via a listener registered with the file transfer
manager.</p>
<b>Usage</b><p>
In order to recieve a file you must first construct an instance of the <b><i>FileTransferManager</i></b>
class. This class has one constructor with one parameter which is your XMPPConnection.
In order to instantiate the manager you should call <i>new FileTransferManager(connection)</i>
<p>Once you have your <b><i>FileTransferManager</i></b> you will need to register a listener
with it. The FileTransferListner interface has one method, <b>fileTransferRequest(request)</b>.
When a request is recieved through this method, you can either accept or reject the
request. To help you make your decision there are several methods in the <b><i>FileTransferRequest</i></b>
class that return information about the transfer request.
<p>To accept the file transfer, call the <b>accept()</b>,
this method will create an <b><i>IncomingFileTransfer</i></b>. After you have the file transfer you may start
to transfer the file by calling the <b>recieveFile(file)</b> method.
The file provided to this method will be where the data from thefile transfer is saved.</p>
<p>Finally, to reject the file transfer the only method you need to call is <b>reject()</b>
on the <b><i>IncomingFileTransfer</i></b>.
<p>For information on monitoring the progress of a file transfer see the <a href="#monitorprogress">monitoring progress</a>
section of this document.
<p>Other means to recieve a file are also provided as part of the <b><i>IncomingFileTransfer</i></b>. Please
consult the Javadoc for more information.
<b>Examples</b><p>
In this example we can see how to approve or reject a file transfer request: <br>
<blockquote>
<pre> <font color="#3f7f5f">// Create the file transfer manager</font>
final FileTransferManager manager = new FileTransferManager(connection);
<font color="#3f7f5f">// Create the listener</font>
manager.addFileTransferListener(new FileTransferListener() {
public void fileTransferRequest(FileTransferRequest request) {
<font color="#3f7f5f">// Check to see if the request should be accepted</font>
if(shouldAccept(request)) {
<font color="#3f7f5f">// Accept it</font>
IncomingFileTransfer transfer = request.accept();
transfer.recieveFile(new File(<font color="#0000FF">"shakespeare_complete_works.txt"</font>));
} else {
<font color="#3f7f5f">// Reject it</font>
request.reject();
}
}
});
</pre>
</blockquote>
<hr>
<div class="subheader"><a name="monitorprogress">Monitoring the progress of a file transfer</a></div><p>
<b>Description</b><p>
While a file transfer is in progress you may wish to monitor the progress of a file transfer.</p>
<b>Usage</b><p>
<p>Both the <b><i>IncomingFileTransfer</i></b> and the <b><i>OutgoingFileTransfer</i></b>
extend the <b><i>FileTransfer</i></b> class which provides several methods to monitor
how a file transfer is progressing:
<ul>
<li><b>getStatus()</b> - The file transfer can be in several states, negotiating, rejected, canceled,
in progress, error, and complete. This method will return which state the file transfer is currently in.
<li><b>getProgress()</b> - if the status of the file transfer is in progress this
method will return a number between 0 and 1, 0 being the transfer has not yet started
and 1 being the transfer is complete. It may also return a -1 if the transfer is not in progress.
<li><b>isDone()</b> - Similar to getProgress() except it returns a <i>boolean</i>. If the state is
rejected, canceled, error, or complete then true will be returned and false otherwise.
<li><b>getError()</b> - If there is an error during the file transfer this method will
return the type of error that occured.
</ul>
<b>Examples</b><p>
In this example we can see how to monitor a file transfer: <br>
<blockquote>
<pre> while(!transfer.isDone()) {
if(transfer.getStatus().equals(Status.ERROR)) {
System.out.println(<font color="#0000FF">"ERROR!!! "</font> + transfer.getError());
} else {
System.out.println(transfer.getStatus());
System.out.println(transfer.getProgress());
}
sleep(1000);
}
</pre>
</blockquote>
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