JTextFieldLimit.java

/**
 * 
 */
package edu.harvard.econcs.turkserver.client;

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

/**
 * @author mao
 *
 */
public class JTextFieldLimit extends PlainDocument {	
	private static final long serialVersionUID = 7940186264256374790L;
	
	private int limit;
	// optional uppercase conversion
	private boolean toUppercase = false;

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

	JTextFieldLimit(int limit, boolean upper) {
		super();
		this.limit = limit;
		toUppercase = upper;
	}

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

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