package railo.commons.net;

import java.io.UnsupportedEncodingException;

import railo.commons.lang.StringUtil;

/**
 * Utility class for HTML form encoding. This class contains static methods
 * for converting a String to the <CODE>application/x-www-form-urlencoded</CODE> MIME
 * format. For more information about HTML form encoding, consult the HTML 
 * <A HREF="http://www.w3.org/TR/html4/">specification</A>. 
 *
 * <p>
 * When encoding a String, the following rules apply:
 *
 * <p>
 * <ul>
 * <li>The alphanumeric characters "<code>a</code>" through
 *     "<code>z</code>", "<code>A</code>" through
 *     "<code>Z</code>" and "<code>0</code>" 
 *     through "<code>9</code>" remain the same.
 * <li>The special characters "<code>.</code>",
 *     "<code>-</code>", "<code>*</code>", and
 *     "<code>_</code>" remain the same. 
 * <li>The space character "<code> </code>" is
 *     converted into a plus sign "<code>+</code>".
 * <li>All other characters are unsafe and are first converted into
 *     one or more bytes using some encoding scheme. Then each byte is
 *     represented by the 3-character string
 *     "<code>%<i>xy</i></code>", where <i>xy</i> is the
 *     two-digit hexadecimal representation of the byte. 
 *     The recommended encoding scheme to use is UTF-8. However, 
 *     for compatibility reasons, if an encoding is not specified, 
 *     then the default encoding of the platform is used.
 * </ul>
 *
 * <p>
 * For example using UTF-8 as the encoding scheme the string "The
 * string ü@foo-bar" would get converted to
 * "The+string+%C3%BC%40foo-bar" because in UTF-8 the character
 * ü is encoded as two bytes C3 (hex) and BC (hex), and the
 * character @ is encoded as one byte 40 (hex).
 *
 * @author  Herb Jellinek
 * @version 1.25, 12/03/01
 * @since   JDK1.0
 */
public class URLEncoder {
    
    /**
     * You can't call the constructor.
     */
    private URLEncoder() { }

    /**
     * Translates a string into <code>x-www-form-urlencoded</code>
     * format. This method uses the platform's default encoding
     * as the encoding scheme to obtain the bytes for unsafe characters.
     *
     * @param   s   <code>String</code> to be translated.
     * @deprecated The resulting string may vary depending on the platform's
     *             default encoding. Instead, use the encode(String,String)
     *             method to specify the encoding.
     * @return  the translated <code>String</code>.
     */
    public static String encode(String s) {
    	s= java.net.URLEncoder.encode(s);
    	if(s.indexOf('+')!=-1)s=StringUtil.replace(s, "+", "%20",false);
    	return s;
    }

    public static String encode(String s, String enc) throws UnsupportedEncodingException {
    	s= java.net.URLEncoder.encode(s, enc);
    	if(s.indexOf('+')!=-1)s=StringUtil.replace(s, "+", "%20",false);
    	return s;
    }
}