code: public boolean setWriter(TransactionImpl tx, Object obj)
  	{
  		try
  		{
  			LockEntry lock = new LockEntry(new Identity(obj,getBroker()).toString(),
  					tx.getGUID(),
  					System.currentTimeMillis(),
  					LockStrategyFactory.getIsolationLevel(obj),
  					LockEntry.LOCK_WRITE);
  
  			setWriterRemote(lock);
  			return true;
  		}
  		catch (Throwable t)
  		{
  			log.error("Cannot set LockEntry for object " + obj + " in transaction " + tx);
  			return false;
  		}
  	}
docs: generate a writer lock entry for transaction tx on object obj
  and write it to the persistent storage.