EncodingUtilities.java

/**
 * 
 */
package org.chris.portmapper.util;

import java.util.HashMap;
import java.util.Map;

/**
 * @author chris
 * @version $Id: EncodingUtilities.java 61 2009-08-15 14:58:46Z christoph $
 */
public class EncodingUtilities {

	private static Map<Character, String> knownEncodings;

	static {
		knownEncodings = new HashMap<Character, String>();
		knownEncodings.put('<', "<");
		knownEncodings.put('>', ">");
		knownEncodings.put('&', "&");
	}

	/**
	 * Replace all special characters with their html entities. This was found
	 * at {@link http
	 * ://www.owasp.org/index.php/How_to_perform_HTML_entity_encoding_in_Java}
	 * 
	 * @param s
	 *            the string in which to replace the special characters.
	 * @return the result of the replacement.
	 */
	public static String htmlEntityEncode(String s) {
		StringBuffer buf = new StringBuffer();
		int len = (s == null ? -1 : s.length());

		for (int i = 0; i < len; i++) {
			char c = s.charAt(i);
			if (c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' || c >= '0'
					&& c <= '9') {
				buf.append(c);
			} else {
				if (knownEncodings.containsKey(c)) {
					buf.append(knownEncodings.get(c));
				} else {
					buf.append("&#" + (int) c + ";");
				}
			}
		}
		return buf.toString();
	}
}