l?is-external=true" title="class or interface in java.io" class="externalLink">Serializable</a>&nbsp;user)</pre>
<div class="block">Sets the user identifier of the websocket channel, so that user-targeted push messages can be sent. All open
 websockets on the same channel and user will receive the same push message from the server. It must implement
 <code>Serializable</code> and preferably have low memory footprint. Suggestion: use
 <code>#{request.remoteUser}</code> or <code>#{someLoggedInUser.id}</code>.