public static String filter(String message) {

	        if (message == null)
	            return (null);

	        char content[] = new char[message.length()];
	        message.getChars(0, message.length(), content, 0);
	        StringBuilder result = new StringBuilder(content.length + 50);
	        for (int i = 0; i < content.length; i++) {
	            switch (content[i]) {
	            case '<':
	                result.append("&lt;");
	                break;
	            case '>':
	                result.append("&gt;");
	                break;
	            case '&':
	                result.append("&amp;");
	                break;
	            case '"':
	                result.append("&quot;");
	                break;
	            default:
	                result.append(content[i]);
	            }
	        }
	        return (result.toString());

	    }