MainClass.java Source code

Introduction

Here is the source code for MainClass.java

Source

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.ScrollPaneConstants;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableModel;

public class MainClass extends JFrame {

    public MainClass() {
        super("Paged JTable Test");
        setSize(300, 200);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        PagingModel pm = new PagingModel();
        pm.setPageSize(20);
        JTable jt = new JTable(pm);

        JScrollPane jsp = PagingModel.createPagingScrollPaneForTable(jt);
        getContentPane().add(jsp, BorderLayout.CENTER);
    }

    public static void main(String args[]) {
        MainClass pt = new MainClass();
        pt.setVisible(true);
    }
}

class Record {
    static String[] headers = { "Record Number", "Batch Number", "Reserved" };
    static int counter;
    String[] data;

    public Record() {
        data = new String[] { "" + (counter++), "" + System.currentTimeMillis(), "Reserved" };
    }

    public String getValueAt(int i) {
        return data[i];
    }

    public static String getColumnName(int i) {
        return headers[i];
    }

    public static int getColumnCount() {
        return headers.length;
    }
}

class PagingModel extends AbstractTableModel {

    protected int pageSize;

    protected int pageOffset;

    protected Record[] data;

    public PagingModel() {
        this(10000, 100);
    }

    public PagingModel(int numRows, int size) {
        data = new Record[numRows];
        pageSize = size;
        for (int i = 0; i < data.length; i++) {
            data[i] = new Record();
        }
    }

    public int getRowCount() {
        return Math.min(pageSize, data.length);
    }

    public int getColumnCount() {
        return Record.getColumnCount();
    }

    public Object getValueAt(int row, int col) {
        int realRow = row + (pageOffset * pageSize);
        return data[realRow].getValueAt(col);
    }

    public String getColumnName(int col) {
        return Record.getColumnName(col);
    }

    public int getPageOffset() {
        return pageOffset;
    }

    public int getPageCount() {
        return (int) Math.ceil((double) data.length / pageSize);
    }

    public int getRealRowCount() {
        return data.length;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int s) {
        if (s == pageSize) {
            return;
        }
        int oldPageSize = pageSize;
        pageSize = s;
        pageOffset = (oldPageSize * pageOffset) / pageSize;
        fireTableDataChanged();
    }

    public void pageDown() {
        if (pageOffset < getPageCount() - 1) {
            pageOffset++;
            fireTableDataChanged();
        }
    }

    public void pageUp() {
        if (pageOffset > 0) {
            pageOffset--;
            fireTableDataChanged();
        }
    }

    public static JScrollPane createPagingScrollPaneForTable(JTable jt) {
        JScrollPane jsp = new JScrollPane(jt);
        TableModel tmodel = jt.getModel();
        if (!(tmodel instanceof PagingModel)) {
            return jsp;
        }

        final PagingModel model = (PagingModel) tmodel;
        final JButton upButton = new JButton("UP");
        upButton.setEnabled(false);
        final JButton downButton = new JButton("DOWN");
        if (model.getPageCount() <= 1) {
            downButton.setEnabled(false);
        }

        upButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                model.pageUp();

                if (model.getPageOffset() == 0) {
                    upButton.setEnabled(false);
                }
                downButton.setEnabled(true);
            }
        });

        downButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                model.pageDown();
                if (model.getPageOffset() == (model.getPageCount() - 1)) {
                    downButton.setEnabled(false);
                }
                upButton.setEnabled(true);
            }
        });

        jsp.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        jsp.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);

        jsp.setCorner(ScrollPaneConstants.UPPER_RIGHT_CORNER, upButton);
        jsp.setCorner(ScrollPaneConstants.LOWER_RIGHT_CORNER, downButton);

        return jsp;
    }
}