default boolean logModified(Logger log){
  if (isModified()) {
    log.finer(this + " is modified");
    return true;
  }
 else {
    return false;
  }
}

default boolean logModified ( Logger log ) { if ( isModified ( ) ) { log . finer ( this + " is modified" ) ; return true ; } else { return false ; } }
log the reason for a modification , returning true if this dependency was modified .
