public void addLineContent(final ZyLineContent line){
  Preconditions.checkNotNull(line,"Internal Error: Line content can't be null");
  m_content.add(line);
}

public void addLineContent ( final ZyLineContent line ) { Preconditions . checkNotNull ( line , "Internal Error: Line content can't be null" ) ; m_content . add ( line ) ; }
adds another line add the end of the label content .
