Joomla redirection

Example of URL Redirection in joomla:
Suppose the user visits our component view page without logging in.
Then we want to force the user to login page (if he is not already logged in) and then redirect back to our page after logging in, and show a custom logout button.

This is a sample code in our component view:

<?php
$user =& JFactory::getUser();
global $mainframe;

if($user->id == 0)
{
$return_url = 'index.php?option=com_comments';
$return_url = urlencode(base64_encode($return_url));
$redirect_url = '&return='.$return_url;
$login_url = 'index.php?option=com_user&view=login';
$finalUrl = $login_url . $redirect_url;
$mainframe->redirect( $finalUrl, 'Please login or register before you post comment' );
}
else
{
 ?>
<table width="800">
<tr><td><?php echo 'Welcome <b>'.$user->name; ?></b></td>
<td align="right">
<form id="login" name="login" method="post" action="index.php?option=com_user">
<div class="readon">
        <input type="submit" value="Logout" class="button" name="Submit">
    </div>

<input type="hidden" value="com_user" name="option">
<input type="hidden" value="logout" name="task">
<input type="hidden" value="aW5kZXgucGhwP29wdGlvbj1jb21fY2Nhdg==" name="return">
</form>
</td>
</tr>
</table>
<?php
}
?>