Component for filtering a list

What is the Java Swing component that would be suitable for creating a filterable list like seen below?

This type of filtering is most easily done using a single column JTable. A table has inbuilt functionality to add a RowSorter which:

..provides the basis for sorting and filtering.

See also How to Use Tables: Sorting and Filtering.

Here is an example for filtering the font family names:

On the left is a more 'list looking' component, while the right hand side shows a component that is clearly a table.

Code

import java.awt.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javax.swing.event.*;
import javax.swing.text.Document;
import javax.swing.table.TableRowSorter;

public class FontFilter {

    private JComponent ui = null;
    JTextField filterText;
    TableRowSorter sorter;

    FontFilter(boolean listLike) {
        initUI(listLike);
    }

    public void initUI(boolean listLike) {
        if (ui != null) {
            return;
        }

        ui = new JPanel(new BorderLayout(4, 4));
        ui.setBorder(new EmptyBorder(4, 4, 4, 4));

        GraphicsEnvironment ge
                = GraphicsEnvironment.getLocalGraphicsEnvironment();
        String[] fonts = ge.getAvailableFontFamilyNames();
        String[][] tableData = new String[fonts.length][1];
        for (int i = 0; i < fonts.length; i++) {
            tableData[i][0] = fonts[i];
        }
        String[] header = {"Fonts"};
        JTable table = new JTable(tableData, header);
        if (listLike) {
            Dimension d = table.getPreferredScrollableViewportSize();
            table.setPreferredScrollableViewportSize(new Dimension(d.width/2,d.height));
            table.setShowGrid(false);
            table.setTableHeader(null);
            table.setFillsViewportHeight(true);
        }
        ui.add(new JScrollPane(table));
        sorter = new TableRowSorter(table.getModel());
        table.setRowSorter(sorter);

        filterText = new JTextField(10);
        ui.add(filterText, BorderLayout.PAGE_START);
        Document doc = filterText.getDocument();
        DocumentListener listener = new DocumentListener() {

            @Override
            public void insertUpdate(DocumentEvent e) {
                newFilter();
            }

            @Override
            public void removeUpdate(DocumentEvent e) {
                newFilter();
            }

            @Override
            public void changedUpdate(DocumentEvent e) {
                newFilter();
            }
        };
        doc.addDocumentListener(listener);
    }
    
    private void newFilter() {
        RowFilter rf = null;
        //If current expression doesn't parse, don't update.
        try {
            rf = RowFilter.regexFilter(filterText.getText(), 0);
        } catch (java.util.regex.PatternSyntaxException e) {
            return;
        }
        sorter.setRowFilter(rf);
    }

    public JComponent getUI() {
        return ui;
    }

    public static void main(String[] args) {
        Runnable r = new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (Exception useDefault) {
                }
                FontFilter o1 = new FontFilter(true);
                FontFilter o2 = new FontFilter(false);

                JFrame f = new JFrame("Font Filter");
                f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                f.setLocationByPlatform(true);

                f.add(o1.getUI(), BorderLayout.LINE_START);
                f.add(o2.getUI(), BorderLayout.CENTER);
                f.pack();
                f.setMinimumSize(f.getSize());

                f.setVisible(true);
            }
        };
        SwingUtilities.invokeLater(r);
    }
}

If you want or have to use only standard Swing components then the method described by @AndrewThompson is the way to go.

But if you are able to use third-party libraries then a good alternative is JXList component included in SwingX project. This component is a JList extension and provides the ability to sort and filter its content plus other interesting features (check SwingLabs Demos).

The following snippet is the basis to make it work:

JXList list = new JXList(listModel);
list.setAutoCreateRowSorter(true);

This is enough to create and install a RowSorter<ListModel, Integer> instance as the list's row sorter which can be retrieved by calling getRowSorter() method. The actual object returned by this method is a ListSortController which inherits from DefaultRowSorter and also implements the non-standard SortController interface.

It is important to keep this class hierarchy in mind because it's possible to supply a RowFilter in different ways. All the following alternatives assume the row sorter is auto-created.

Note: IMO the first method is the preferred one because we can delegate the dirty work of down-casting the row sorter to supply a row filter to the component.

1. Set the row filter directly on the list

list.setRowFilter(rowFilter);

This is a convenience method to set the row filter. However it is required by contract that the actual list's row sorter be a SortController compliant instance. Otherwise the setRowFilter(...) call has no effect.

2. Cast the row sorter as SortController

SortController<ListModel> sortController 
        = (SortController<ListModel>)list.getRowSorter();
sortController.setRowFilter(rowFilter);

The SortController interface provides a method to set the row filter which is used to by-pass the row filter in the method # 1.

3. Cast the row sorter as DefaultRowSorter

DefaultRowSorter<ListModel, Integer> sorter 
        = (DefaultRowSorter<ListModel, Integer>)list.getRowSorter();
sorter.setRowFilter(rowFilter);

This method is the same than when we are working with JTable.

Example

Here is a simple demo about filtering with JXList. Once again please check SingLabs Demos for better examples.

import java.awt.BorderLayout;
import java.awt.GraphicsEnvironment;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.ListModel;
import javax.swing.RowFilter;
import javax.swing.SwingUtilities;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import org.jdesktop.swingx.JXList;    

public class FilterListDemo {

    private JXList list;

    private void createAndShowGui() {

        final JTextField filterText = new JTextField(30);
        filterText.getDocument().addDocumentListener(new DocumentListener() {
            @Override
            public void insertUpdate(DocumentEvent e) {
                FilterListDemo.this.createFilter(filterText.getText(), false);
            }

            @Override
            public void removeUpdate(DocumentEvent e) {
                FilterListDemo.this.createFilter(filterText.getText(), false);
            }

            @Override
            public void changedUpdate(DocumentEvent e) {
                FilterListDemo.this.createFilter(filterText.getText(), false);
            }
        });

        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        String[] fonts = ge.getAvailableFontFamilyNames();

        list = new JXList(fonts);
        list.setAutoCreateRowSorter(true);

        JPanel content = new JPanel(new BorderLayout(8,8));
        content.add(filterText, BorderLayout.PAGE_START);
        content.add(new JScrollPane(list), BorderLayout.CENTER);
        content.setBorder(BorderFactory.createEmptyBorder(8,8,8,8));

        JFrame frame = new JFrame("Filter List Demo");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.add(content);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private void createFilter(String text, final boolean caseSensitive) {

        final String filterText = caseSensitive ? text : text.toUpperCase();

        list.setRowFilter(new RowFilter<ListModel, Integer>() {
            @Override
            public boolean include(RowFilter.Entry<? extends ListModel
                    , ? extends Integer> entry) {

                String entryValue = caseSensitive 
                        ? entry.getStringValue(0) 
                        : entry.getStringValue(0).toUpperCase();

                return filterText == null 
                        || filterText.trim().isEmpty() 
                        || entryValue.contains(filterText.trim());
            }
        });
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new FilterListDemo().createAndShowGui();
            }
        });
    }
}