Tutoriais interessantes sobre JPA no Netbeans

http://wiki.netbeans.org/JavaPersistenceApi

NumericTextField

#exemplo retirado de: http://faq.javaranch.com/java/NumericTextField

import java.awt.BorderLayout;
import java.util.regex.Pattern;

import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.PlainDocument;

@SuppressWarnings("serial")
public class JavaRanch extends JPanel
{
private JLabel inputLabel;
private NumericTextField inputField;

public JavaRanch()
{
super(new BorderLayout());

inputLabel = new JLabel("Enter value: ");
inputField = new NumericTextField();
inputField.setColumns(10);

this.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
this.add(inputLabel, BorderLayout.WEST);
this.add(inputField, BorderLayout.CENTER);
}

public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
try
{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

JFrame frame = new JFrame("Numeric Text Field Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.add(new JavaRanch());

frame.pack();
frame.setVisible(true);
}
catch (Exception e)
{
e.printStackTrace();
}
}
});
}
}

@SuppressWarnings("serial")
class NumericTextField extends JTextField
{

@Override
protected Document createDefaultModel()
{
return new NumericDocument();
}

private static class NumericDocument extends PlainDocument
{
// The regular expression to match input against (zero or more digits)
private final static Pattern DIGITS = Pattern.compile("\\d*");

@Override
public void insertString(int offs, String str, AttributeSet a) throws BadLocationException
{
// Only insert the text if it matches the regular expression
if (str != null && DIGITS.matcher(str).matches())
super.insertString(offs, str, a);
}
}
}

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