Populate JTable with large number of rows

Question

I would like to populate a JTable during runtime with many rows (lets say 10000). But all my attempts are very poor and inefficient.

Starting point is the addData method which gets a List of Objects representing a row. I tried to fill the table via a SwingWorker but this only works for small data for me.

Another attempt was setting the data directly without using any kind of thread, but this is also very slow, at least the UI isn't blocked like its the case with the SwingWorker.

So how do you do this is general? The table should be filled row by row or chunkwise but not all by one and the vertical scrollbar should be scrollable meanwhile.

My TableModel:

public class MyTableModel extends AbstractTableModel {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    String[] columnNames;   
    public Map<Long, ErrorMessage> data = new LinkedHashMap<Long, ErrorMessage>(); 

    public MyTableModel(String[] header) {
        columnNames = header;
    }

    public String getColumnName(int col) {
        return columnNames[col].toString();
    }

    @Override
    public int getColumnCount() {
        return columnNames.length;
    }

    @Override
    public int getRowCount() {
        return data.size();
    }


    @Override
    public Object getValueAt(int row, int col) {
            .
            .
        return value;
    }

    public void addRow(long id, MyDataObject o) {
            data.put(id, m);
            fireTableRowsInserted(0,nqm_messages.size()-1);         
    }

}

SwingWorker implementation:

class TableSwingWorker extends SwingWorker<MyTableModel, MyDataObject> {

    private final MyTableModel tableModel;
    List<MyDataObject> messages;

    public TableSwingWorker(MyTableModel tableModel, List<MyDataObject> dataList) {
        this.tableModel = tableModel;
            this.messages = new LinkedList<MyDataObject>(mm);
    }

    @Override
    protected MyTableModel doInBackground() throws Exception {

        for(MyDataObject s : messages) {
            publish(s);
        }

        return tableModel;
    }

    @Override
    protected void process(List<MyDataObject> chunks) {
        for(MyDataObject row : chunks){
            Long l = Long.parseLong(row.getId());
            tableModel.addRow(l, row);
        }
    }
}

Add Objects to JTable:

public void addData(List<MyDataObject> o) {

    MyTableModel m = (MyTableModel)table.getModel();

    (new TableSwingWorker(m,o)).execute();

    //for(int i=0; i < mm.size();i++) {
    //    long l = Long.parseLong(mm.get(i).getId());
    //    m.addRow(l, mm.get(i));
    //}
}

Answer 1

So, a number of things have being identified from the comments...

• You need to correctly fire the row inserted method, indicating only those rows that have being added and where they have being updated. This very important, as the the table has being optimised for speed
• You should provide batch add method for your table model, allowing you to more easily add multiple rows in a single or as few steps as possible
• You should have the SwingWorker periodically sleep or yield, to allow it time to publish the results.

So, in this example, I'm adding 1, 000, 000 rows. In my test it took slightly under 1 second...

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingWorker;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.DefaultTableCellRenderer;

public class TestTableLoad01 {

    public static void main(String[] args) {
        new TestTableLoad01();
    }

    public TestTableLoad01() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                MyTableModel model = new MyTableModel();
                JTable table = new JTable(model);
                table.setDefaultRenderer(Date.class, new TimeCellRenderer());

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);

                TableSwingWorker worker = new TableSwingWorker(model);
                worker.execute();

            }
        });
    }

    public class TimeCellRenderer extends DefaultTableCellRenderer {

        private DateFormat df;

        public TimeCellRenderer() {
            df = new SimpleDateFormat("HH:mm:ss");
        }

        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {

            if (value instanceof Date) {

                value = df.format(value);

            }

            super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column); 

            return this;

        }

    }

    public class MyTableModel extends AbstractTableModel {

        private String[] columnNames = new String[]{"Date", "Row"};
        private List<RowData> data;

        public MyTableModel() {
            data = new ArrayList<>(25);
        }

        @Override
        public Class<?> getColumnClass(int columnIndex) {
            return columnIndex == 0 ? Date.class : Integer.class;
        }

        @Override
        public String getColumnName(int col) {
            return columnNames[col];
        }

        @Override
        public int getColumnCount() {
            return columnNames.length;
        }

        @Override
        public int getRowCount() {
            return data.size();
        }

        @Override
        public Object getValueAt(int row, int col) {
            RowData value = data.get(row);
            return col == 0 ? value.getDate() : value.getRow();
        }

        public void addRow(RowData value) {
            int rowCount = getRowCount();
            data.add(value);
            fireTableRowsInserted(rowCount, rowCount);
        }

        public void addRows(RowData... value) {
            addRows(Arrays.asList(value));
        }

        private void addRows(List<RowData> rows) {
            int rowCount = getRowCount();
            data.addAll(rows);
            fireTableRowsInserted(rowCount, getRowCount() - 1);
        }
    }

    public class RowData {

        private Date date;
        private int row;

        public RowData(int row) {
            this.date = new Date();
            this.row = row;
        }

        public Date getDate() {
            return date;
        }

        public int getRow() {
            return row;
        }
    }

    public class TableSwingWorker extends SwingWorker<MyTableModel, RowData> {

        private final MyTableModel tableModel;

        public TableSwingWorker(MyTableModel tableModel) {
            this.tableModel = tableModel;
        }

        @Override
        protected MyTableModel doInBackground() throws Exception {

            // This is a deliberate pause to allow the UI time to render
            Thread.sleep(2000);

            System.out.println("Start polulating");

            for (int index = 0; index < 1000000; index++) {

                RowData data = new RowData(index);
                publish(data);

                Thread.yield();

            }

            return tableModel;
        }

        @Override
        protected void process(List<RowData> chunks) {
            System.out.println("Adding " + chunks.size() + " rows");
            tableModel.addRows(chunks);
        }
    }
}