if (dialogLocks == null) {
dialogLocks = new HashSet<SipApplicationSessionImpl>();
}
if (dialogLocks.add(sas)) {
sas.lockForegroundWithRetry();
}
} else {
if (logger.isLoggable(Level.FINE)) {
logger.log(Level.FINE, "attempted to lock df {0} but it has no sas. Not obtaining the lock", new Object[] {
df