IPullChannel channel = getChannel(channelId);
if (channel == null) {
return null;
}
IChannelPreferences cPrefs = channel.newDefaultPreferences();
IParams fullParams = new Params().setAll(cPrefs.getParams()).setAll(params);
StringBuilder buf = new StringBuilder(_baseUrl);
buf.append(_mountPath).append(_pullPrefix).append(channelId).append("/").append(userId);