public boolean retainAll(AbstractLongList other){
  if (other.size() == 0) {
    if (size == 0)     return false;
    setSize(0);
    return true;
  }
  int limit=other.size() - 1;
  int j=0;
  for (int i=0; i < size; i++) {
    if (other.indexOfFromTo(getQuick(i),0,limit) >= 0)     setQuick(j++,getQuick(i));
  }
  boolean modified=(j != size);
  setSize(j);
  return modified;
}

public boolean retainAll ( AbstractLongList other ) { if ( other . size ( ) == 0 ) { if ( size == 0 ) return false ; setSize ( 0 ) ; return true ; } int limit = other . size ( ) - 1 ; int j = 0 ; for ( int i = 0 ; i < size ; i ++ ) { if ( other . indexOfFromTo ( getQuick ( i ) , 0 , limit ) >= 0 ) setQuick ( j ++ , getQuick ( i ) ) ; } boolean modified = ( j != size ) ; setSize ( j ) ; return modified ; }
retains ( keeps ) only the elements in the receiver that are contained in the specified other list . in other words , removes from the receiver all of its elements that are not contained in the specified other list .
