if(log.isDebugEnabled()) log.debug(local_addr + ": changed role to " + new_impl.getClass().getName());
if(log.isDebugEnabled()) { String msg=(local_addr != null? local_addr.toString()+" " : "") + "changed role to " + new_impl.getClass().getName(); log.debug(msg); }
    public void setImpl(GmsImpl new_impl) {        synchronized(impl_mutex) {            impl=new_impl;            if(log.isDebugEnabled())                log.debug(local_addr + ": changed role to " + new_impl.getClass().getName());        }    }