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import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.DocumentFilter;
public class MainClass {
public static void main(String args[]) {
JFrame frame = new JFrame("Range Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridLayout(3, 2));
frame.add(new JLabel("Range: 0-255"));
JTextField textFieldOne = new JTextField();
Document textDocOne = textFieldOne.getDocument();
DocumentFilter filterOne = new IntegerRangeDocumentFilter(0, 255);
((AbstractDocument) textDocOne).setDocumentFilter(filterOne);
frame.add(textFieldOne);
frame.setSize(250, 150);
frame.setVisible(true);
}
}
class IntegerRangeDocumentFilter extends DocumentFilter {
int minimum, maximum;
int currentValue = 0;
public IntegerRangeDocumentFilter(int minimum, int maximum) {
this.minimum = minimum;
this.maximum = maximum;
}
public void insertString(DocumentFilter.FilterBypass fb, int offset, String string,
AttributeSet attr) throws BadLocationException {
if (string == null) {
return;
} else {
String newValue;
Document doc = fb.getDocument();
int length = doc.getLength();
if (length == 0) {
newValue = string;
} else {
String currentContent = doc.getText(0, length);
StringBuffer currentBuffer = new StringBuffer(currentContent);
currentBuffer.insert(offset, string);
newValue = currentBuffer.toString();
}
currentValue = checkInput(newValue, offset);
fb.insertString(offset, string, attr);
}
}
public void remove(DocumentFilter.FilterBypass fb, int offset, int length)
throws BadLocationException {
Document doc = fb.getDocument();
int currentLength = doc.getLength();
String currentContent = doc.getText(0, currentLength);
String before = currentContent.substring(0, offset);
String after = currentContent.substring(length + offset, currentLength);
String newValue = before + after;
currentValue = checkInput(newValue, offset);
fb.remove(offset, length);
}
public void replace(DocumentFilter.FilterBypass fb, int offset, int length, String text,
AttributeSet attrs) throws BadLocationException {
Document doc = fb.getDocument();
int currentLength = doc.getLength();
String currentContent = doc.getText(0, currentLength);
String before = currentContent.substring(0, offset);
String after = currentContent.substring(length + offset, currentLength);
String newValue = before + (text == null ? "" : text) + after;
currentValue = checkInput(newValue, offset);
fb.replace(offset, length, text, attrs);
}
private int checkInput(String proposedValue, int offset) throws BadLocationException {
int newValue = 0;
if (proposedValue.length() > 0) {
try {
newValue = Integer.parseInt(proposedValue);
} catch (NumberFormatException e) {
throw new BadLocationException(proposedValue, offset);
}
}
if ((minimum <= newValue) && (newValue <= maximum)) {
return newValue;
} else {
throw new BadLocationException(proposedValue, offset);
}
}
}
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