Add row with empty fields in a JTable

I have a AbstractTableModel only that I do not know how to add blank lines, when I hit the add line button in my frame I want it to call a method called addLine () from my TableTable, can anyone help me?

    public class ModeloTabela2 extends AbstractTableModel {
    private ArrayList linhas = new ArrayList();
    private String[] colunas = {"DATA", "EVOLUÇÃO"};

    public boolean isCellEditable(int linha, int coluna) {
        return true;
    }

    public ArrayList getLinhas(){
        return linhas;
    }
    public void setLinhas(ArrayList dados){
        linhas = dados;
    }
    public String[] getColunas(){
        return colunas;
    }
    public void setColunas(String[] nomes){
        colunas = nomes;
    }
    public int getColumnCount(){
        return colunas.length;
    }
    public int getRowCount(){
        return linhas.size();
    }
    public String getColumnName(int numCol){
        return colunas[numCol];
    }
    public Object getValueAt(int numLin, int numCol){
        Object[] linha = (Object[])getLinhas().get(numLin);
        return linha[numCol];
    }
    public Class<?> getColumnClass(int coluna) {
        switch(coluna){
        case 0:
            return String.class;
        case 1:
            return String.class;
        default:
            return String.class;
        }

    }
    public void addLinha(){       //Aqui eu adicionaria a linha em branco...

    }

}