Problems with Rowfilter output

Question

I’m working with Documentlistener and Rowfilter, and I realized that my filter is taking the data that I type, and searching for correspondence in all the columns of my table. I would like to know, how could I choose the column that he should compare, and also, how should I make it so that he takes only the words that the beginning equals what was typed.

Example query:

Ukraine begins with U

Brazil

Portugal Has the letter U, however, does not start with the letter U, should ignore - la

USA starts with U

Type U, he would only show me USA and Ukraine.

Code example:

package teste;

import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.RowFilter;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;
import javax.swing.table.TableRowSorter;

public class TestX extends JFrame {

    private String[] colunas
            = {"Country", "Capital", "Population in Millions", "Democracy"};

    private Object[][] dados = {
        {"USA", "Washington DC", 280, true},
        {"Canada", "Ottawa", 32, true},
        {"United Kingdom", "London", 60, true},
        {"Germany", "Berlin", 83, true},
        {"France", "Paris", 60, true},
        {"Norway", "Oslo", 4.5, true},
        {"India", "New Delhi", 1046, true}
    };

    private DefaultTableModel model = new DefaultTableModel(dados, colunas);
    private JTable tabela = new JTable(model);

    private TableRowSorter<TableModel> rowSorter = new TableRowSorter<>(tabela.getModel());

    private JTextField barraPesquisa = new JTextField();
    private JButton botao = new JButton("OK");

    private JPanel painel = new JPanel();
    private JLabel label = new JLabel();

    public TestX() {
        add(x());
        setSize(600, 400);
        setLocationRelativeTo(null);
        setVisible(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

    public JComponent x() {
        JPanel painelX = new JPanel();
        painelX.setLayout(null);

        painelX.add(barraPesquisa);
        barraPesquisa.setBounds(20, 10, 270, 27);
        painelX.add(botao);
        botao.setBounds(300, 10, 65, 27);

        barraPesquisa.getDocument().addDocumentListener(new DocumentListener() {
            @Override
            public void insertUpdate(DocumentEvent e) {
                String text = barraPesquisa.getText();

                //model.setRowCount(0); // limpar as linhas
                if (text.trim().length() == 0) {
                    barraPesquisa.setText("Digite aqui..");
                    rowSorter.setRowFilter(null);
                } else {
                    rowSorter.setRowFilter(RowFilter.regexFilter("(?i)" + text));
                    model.getRowCount();
                }
                label.setText(rowSorter.getViewRowCount() + " resultados encontrados");
            }

            @Override
            public void removeUpdate(DocumentEvent e) {
                String text = barraPesquisa.getText();
                if (text.trim().length() == 0) {
                    rowSorter.setRowFilter(null);
                } else {
                    rowSorter.setRowFilter(RowFilter.regexFilter("(?i)" + text));
                }
                label.setText(rowSorter.getViewRowCount() + " resultados encontrados");
            }

            @Override
            public void changedUpdate(DocumentEvent e) {

            }
        });

        tabela.setRowSorter(rowSorter);

        painelX.add(tabela);
        tabela.setBounds(5, 100, 500, 150);

        painelX.add(label);
        label.setBounds(10, 250, 150, 30);
        label.setText(model.getRowCount() + " resultados encontrados!");

        painelX.setBounds(1, 1, 600, 400);
        return painelX;
    }

    public static void main(String[] args) {
        TestX t = new TestX();
    }
}

Answer 1

If it’s just to limit the filter to search from the initial words of the table, just change your filter to:

rowSorter.setRowFilter(RowFilter.regexFilter("^(?i)" + text));

The ^ will cause the filter to be applied from the beginning of the line, and not at any position that the searched term is found.

Other Patterns can be consulted on this page

---

You can also create different filters for each column or limit it to just a few, using some class methods RowFilter.Starting from the code presented in the question, to restrict the search only to the first column, just inform the column index in the RowFilter.regexFilter():

// o indice 0 filtrará apenas a primeira coluna
rowSorter.setRowFilter(RowFilter.regexFilter("^(?i)" + text, 0));