Limit JTextField input to a maximum length : Document « Swing Event « Java Tutorial

1. Java Tutorial
2. Swing Event
3. Document

import javax.swing.JTextField;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;

class JTextFieldLimit extends PlainDocument {
  private int limit;

  JTextFieldLimit(int limit) {
    super();
    this.limit = limit;
  }

  public void insertString(int offset, String str, AttributeSet attr)
      throws BadLocationException {
    if (str == null)
      return;

    if ((getLength() + str.length()) <= limit) {
      super.insertString(offset, str, attr);
    }
  }
}

public class Main {
  public static void main(String[] argv) {

    JTextField textfield1 = new JTextField(15);
    textfield1.setDocument(new JTextFieldLimit(10));
  }
}

15.12.Document
	15.12.1.	Custom Document Filter
	15.12.2.	extends PlainDocument to create a float value type text field
	15.12.3.	extends PlainDocument to create alpha and numeric value based field field
	15.12.4.	Element Walker
	15.12.5.	Implement a document cleaner that maps lowercase letters to uppercase
	15.12.6.	Limit JTextField input to a maximum length