Paging JTable(Table) Model with an input field for dynamically altering the size of a page.
/*
Java Swing, 2nd Edition
By Marc Loy, Robert Eckstein, Dave Wood, James Elliott, Brian Cole
ISBN: 0-596-00408-7
Publisher: O'Reilly
*/
// PagingTester2.java
//A quick application that demonstrates the PagingModel. This version has
//an input field for dynamically altering the size of a page.
//
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Polygon;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.ScrollPaneConstants;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableModel;
public class PagingTester2 extends JFrame {
public PagingTester2() {
super("Paged JTable Test");
setSize(300, 200);
setDefaultCloseOperation(EXIT_ON_CLOSE);
final PagingModel pm = new PagingModel();
final JTable jt = new JTable(pm);
// Use our own custom scrollpane.
JScrollPane jsp = PagingModel.createPagingScrollPaneForTable(jt);
getContentPane().add(jsp, BorderLayout.CENTER);
// Property features testing
JPanel p = new JPanel();
p.add(new JLabel("Page Size: "));
final JTextField tf = new JTextField("100", 6);
p.add(tf);
tf.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
pm.setPageSize(Integer.parseInt(tf.getText()));
}
});
getContentPane().add(p, BorderLayout.SOUTH);
}
public static void main(String args[]) {
PagingTester2 pt = new PagingTester2();
pt.setVisible(true);
}
}
//PagingModel.java
//A larger table model that performs "paging" of its data. This model
//reports a small number of rows (like 100 or so) as a "page" of data. You
//can switch pages to view all of the rows as needed using the pageDown()
//and pageUp() methods. Presumably, access to the other pages of data is
//dictated by other GUI elements such as up/down buttons, or maybe a text
//field that allows you to enter the page number you want to display.
//
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;
// Fill our table with random data (from the Record() constructor).
for (int i = 0; i < data.length; i++) {
data[i] = new Record();
}
}
// Return values appropriate for the visible table part.
public int getRowCount() {
return Math.min(pageSize, data.length);
}
public int getColumnCount() {
return Record.getColumnCount();
}
// Work only on the visible part of the table.
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);
}
// Use this method to figure out which page you are on.
public int getPageOffset() {
return pageOffset;
}
public int getPageCount() {
return (int) Math.ceil((double) data.length / pageSize);
}
// Use this method if you want to know how big the real table is . . . we
// could also write "getRealValueAt()" if needed.
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();
/*
* if (pageSize < oldPageSize) { fireTableRowsDeleted(pageSize,
* oldPageSize - 1); } else { fireTableRowsInserted(oldPageSize,
* pageSize - 1); }
*/
}
// Update the page offset and fire a data changed (all rows).
public void pageDown() {
if (pageOffset < getPageCount() - 1) {
pageOffset++;
fireTableDataChanged();
}
}
// Update the page offset and fire a data changed (all rows).
public void pageUp() {
if (pageOffset > 0) {
pageOffset--;
fireTableDataChanged();
}
}
// We provide our own version of a scrollpane that includes
// the page up and page down buttons by default.
public static JScrollPane createPagingScrollPaneForTable(JTable jt) {
JScrollPane jsp = new JScrollPane(jt);
TableModel tmodel = jt.getModel();
// Don't choke if this is called on a regular table . . .
if (!(tmodel instanceof PagingModel)) {
return jsp;
}
// Okay, go ahead and build the real scrollpane
final PagingModel model = (PagingModel) tmodel;
final JButton upButton = new JButton(new ArrowIcon(ArrowIcon.UP));
upButton.setEnabled(false); // starts off at 0, so can't go up
final JButton downButton = new JButton(new ArrowIcon(ArrowIcon.DOWN));
if (model.getPageCount() <= 1) {
downButton.setEnabled(false); // One page...can't scroll down
}
upButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
model.pageUp();
// If we hit the top of the data, disable the up button.
if (model.getPageOffset() == 0) {
upButton.setEnabled(false);
}
downButton.setEnabled(true);
}
});
downButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
model.pageDown();
// If we hit the bottom of the data, disable the down button.
if (model.getPageOffset() == (model.getPageCount() - 1)) {
downButton.setEnabled(false);
}
upButton.setEnabled(true);
}
});
// Turn on the scrollbars; otherwise we won't get our corners.
jsp
.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
jsp
.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
// Add in the corners (page up/down).
jsp.setCorner(ScrollPaneConstants.UPPER_RIGHT_CORNER, upButton);
jsp.setCorner(ScrollPaneConstants.LOWER_RIGHT_CORNER, downButton);
return jsp;
}
}
//Record.java
//A simple data structure for use with the PagingModel demo.
//
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;
}
}
//ArrowIcon.java
//A simple implementation of the Icon interface that can make
//Up and Down arrows.
//
class ArrowIcon implements Icon {
public static final int UP = 0;
public static final int DOWN = 1;
private int direction;
private Polygon pagePolygon = new Polygon(new int[] { 2, 4, 4, 10, 10, 2 },
new int[] { 4, 4, 2, 2, 12, 12 }, 6);
private int[] arrowX = { 4, 9, 6 };
private Polygon arrowUpPolygon = new Polygon(arrowX,
new int[] { 10, 10, 4 }, 3);
private Polygon arrowDownPolygon = new Polygon(arrowX,
new int[] { 6, 6, 11 }, 3);
public ArrowIcon(int which) {
direction = which;
}
public int getIconWidth() {
return 14;
}
public int getIconHeight() {
return 14;
}
public void paintIcon(Component c, Graphics g, int x, int y) {
g.setColor(Color.black);
pagePolygon.translate(x, y);
g.drawPolygon(pagePolygon);
pagePolygon.translate(-x, -y);
if (direction == UP) {
arrowUpPolygon.translate(x, y);
g.fillPolygon(arrowUpPolygon);
arrowUpPolygon.translate(-x, -y);
} else {
arrowDownPolygon.translate(x, y);
g.fillPolygon(arrowDownPolygon);
arrowDownPolygon.translate(-x, -y);
}
}
}
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