mimeutility.java

java Email you can use it to send email to others

	try {
	    String decodedWord;
	    if (word.length() > 0) {
		// Extract the bytes from word
		ByteArrayInputStream bis = 
		    new ByteArrayInputStream(ASCIIUtility.getBytes(word));

		// Get the appropriate decoder
		InputStream is;
		if (encoding.equalsIgnoreCase("B")) 
		    is = new BASE64DecoderStream(bis);
		else if (encoding.equalsIgnoreCase("Q"))
		    is = new QDecoderStream(bis);
		else
		    throw new UnsupportedEncodingException(
				    "unknown encoding: " + encoding);

		// For b64 & q, size of decoded word <= size of word. So
		// the decoded bytes must fit into the 'bytes' array. This
		// is certainly more efficient than writing bytes into a
		// ByteArrayOutputStream and then pulling out the byte[]
		// from it.
		int count = bis.available();
		byte[] bytes = new byte[count];
		// count is set to the actual number of decoded bytes 
		count = is.read(bytes, 0, count);

		// Finally, convert the decoded bytes into a String using
		// the specified charset
		decodedWord = count <= 0 ? "" :
				new String(bytes, 0, count, charset);
	    } else {
		// no characters to decode, return empty string
		decodedWord = "";
	    }
	    if (pos + 2 < eword.length()) {
		// there's still more text in the string
		String rest = eword.substring(pos + 2);
		if (!decodeStrict)
		    rest = decodeInnerWords(rest);
		decodedWord += rest;
	    }
	    return decodedWord;
	} catch (UnsupportedEncodingException uex) {
	    // explicitly catch and rethrow this exception, otherwise
	    // the below IOException catch will swallow this up!
	    throw uex;
	} catch (IOException ioex) {
	    // Shouldn't happen.
	    throw new ParseException(ioex.toString());
	} catch (IllegalArgumentException iex) {
	    /* An unknown charset of the form ISO-XXX-XXX, will cause
	     * the JDK to throw an IllegalArgumentException ... Since the
	     * JDK will attempt to create a classname using this string,
	     * but valid classnames must not contain the character '-',
	     * and this results in an IllegalArgumentException, rather than
	     * the expected UnsupportedEncodingException. Yikes
	     */
	    throw new UnsupportedEncodingException(charset);
	}
    }

    /**
     * Look for encoded words within a word.  The MIME spec doesn't
     * allow this, but many broken mailers, especially Japanese mailers,
     * produce such incorrect encodings.
     */
    private static String decodeInnerWords(String word)
				throws UnsupportedEncodingException {
	int start = 0, i;
	StringBuffer buf = new StringBuffer();
	while ((i = word.indexOf("=?", start)) >= 0) {
	    buf.append(word.substring(start, i));
	    // find first '?' after opening '=?' - end of charset
	    int end = word.indexOf('?', i + 2);
	    if (end < 0)
		break;
	    // find next '?' after that - end of encoding
	    end = word.indexOf('?', end + 1);
	    if (end < 0)
		break;
	    // find terminating '?='
	    end = word.indexOf("?=", end + 1);
	    if (end < 0)
		break;
	    String s = word.substring(i, end + 2);
	    try {
		s = decodeWord(s);
	    } catch (ParseException pex) {
		// ignore it, just use the original string
	    }
	    buf.append(s);
	    start = end + 2;
	}
	if (start == 0)
	    return word;
	if (start < word.length())
	    buf.append(word.substring(start));
	return buf.toString();
    }

    /**
     * A utility method to quote a word, if the word contains any
     * characters from the specified 'specials' list.<p>
     *
     * The <code>HeaderTokenizer</code> class defines two special
     * sets of delimiters - MIME and RFC 822. <p>
     *
     * This method is typically used during the generation of 
     * RFC 822 and MIME header fields.
     *
     * @param	word	word to be quoted
     * @param	specials the set of special characters
     * @return		the possibly quoted word
     * @see	javax.mail.internet.HeaderTokenizer#MIME
     * @see	javax.mail.internet.HeaderTokenizer#RFC822
     */
    public static String quote(String word, String specials) {
	int len = word.length();

	/*
	 * Look for any "bad" characters, Escape and
	 *  quote the entire string if necessary.
	 */
	boolean needQuoting = false;
	for (int i = 0; i < len; i++) {
	    char c = word.charAt(i);
	    if (c == '"' || c == '\\' || c == '\r' || c == '\n') {
		// need to escape them and then quote the whole string
		StringBuffer sb = new StringBuffer(len + 3);
		sb.append('"');
		sb.append(word.substring(0, i));
		int lastc = 0;
		for (int j = i; j < len; j++) {
		    char cc = word.charAt(j);
		    if ((cc == '"') || (cc == '\\') || 
			(cc == '\r') || (cc == '\n'))
			if (cc == '\n' && lastc == '\r')
			    ;	// do nothing, CR was already escaped
			else
			    sb.append('\\');	// Escape the character
		    sb.append(cc);
		    lastc = cc;
		}
		sb.append('"');
		return sb.toString();
	    } else if (c < 040 || c >= 0177 || specials.indexOf(c) >= 0)
		// These characters cause the string to be quoted
		needQuoting = true;
	}

	if (needQuoting) {
	    StringBuffer sb = new StringBuffer(len + 2);
	    sb.append('"').append(word).append('"');
	    return sb.toString();
	} else 
	    return word;
    }

    /**
     * Fold a string at linear whitespace so that each line is no longer
     * than 76 characters, if possible.  If there are more than 76
     * non-whitespace characters consecutively, the string is folded at
     * the first whitespace after that sequence.  The parameter
     * <code>used</code> indicates how many characters have been used in
     * the current line; it is usually the length of the header name. <p>
     *
     * Note that line breaks in the string aren't escaped; they probably
     * should be.
     *
     * @param	used	characters used in line so far
     * @param	s	the string to fold
     * @return		the folded string
     * @since		JavaMail 1.4
     */
    public static String fold(int used, String s) {
	if (!foldText)
	    return s;

	int end;
	char c;
	// Strip trailing spaces and newlines
	for (end = s.length() - 1; end >= 0; end--) {
	    c = s.charAt(end);
	    if (c != ' ' && c != '\t' && c != '\r' && c != '\n')
		break;
	}
	if (end != s.length() - 1)
	    s = s.substring(0, end + 1);

	// if the string fits now, just return it
	if (used + s.length() <= 76)
	    return s;

	// have to actually fold the string
	StringBuffer sb = new StringBuffer(s.length() + 4);
	char lastc = 0;
	while (used + s.length() > 76) {
	    int lastspace = -1;
	    for (int i = 0; i < s.length(); i++) {
		if (lastspace != -1 && used + i > 76)
		    break;
		c = s.charAt(i);
		if (c == ' ' || c == '\t')
		    if (!(lastc == ' ' || lastc == '\t'))
			lastspace = i;
		lastc = c;
	    }
	    if (lastspace == -1) {
		// no space, use the whole thing
		sb.append(s);
		s = "";
		used = 0;
		break;
	    }
	    sb.append(s.substring(0, lastspace));
	    sb.append("\r\n");
	    lastc = s.charAt(lastspace);
	    sb.append(lastc);
	    s = s.substring(lastspace + 1);
	    used = 1;
	}
	sb.append(s);
	return sb.toString();
    }

    /**
     * Unfold a folded header.  Any line breaks that aren't escaped and
     * are followed by whitespace are removed.
     *
     * @param	s	the string to unfold
     * @return		the unfolded string
     * @since		JavaMail 1.4
     */
    public static String unfold(String s) {
	if (!foldText)
	    return s;

	StringBuffer sb = null;
	int i;
	while ((i = indexOfAny(s, "\r\n")) >= 0) {
	    int start = i;
	    int l = s.length();
	    i++;		// skip CR or NL
	    if (i < l && s.charAt(i - 1) == '\r' && s.charAt(i) == '\n')
		i++;	// skip LF
	    if (start == 0 || s.charAt(start - 1) != '\\') {
		char c;
		// if next line starts with whitespace, skip all of it
		// XXX - always has to be true?
		if (i < l && ((c = s.charAt(i)) == ' ' || c == '\t')) {
		    i++;	// skip whitespace
		    while (i < l && ((c = s.charAt(i)) == ' ' || c == '\t'))
			i++;
		    if (sb == null)
			sb = new StringBuffer(s.length());
		    if (start != 0) {
			sb.append(s.substring(0, start));
			sb.append(' ');
		    }
		    s = s.substring(i);
		    continue;
		}
		// it's not a continuation line, just leave it in
		if (sb == null)
		    sb = new StringBuffer(s.length());
		sb.append(s.substring(0, i));
		s = s.substring(i);
	    } else {
		// there's a backslash at "start - 1"
		// strip it out, but leave in the line break
		if (sb == null)
		    sb = new StringBuffer(s.length());
		sb.append(s.substring(0, start - 1));
		sb.append(s.substring(start, i));
		s = s.substring(i);
	    }
	}
	if (sb != null) {
	    sb.append(s);
	    return sb.toString();
	} else
	    return s;
    }

    /**
     * Return the first index of any of the characters in "any" in "s",
     * or -1 if none are found.
     *
     * This should be a method on String.
     */
    private static int indexOfAny(String s, String any) {
	return indexOfAny(s, any, 0);
    }

    private static int indexOfAny(String s, String any, int start) {
	try {
	    int len = s.length();
	    for (int i = start; i < len; i++) {
		if (any.indexOf(s.charAt(i)) >= 0)
		    return i;
	    }
	    return -1;
	} catch (StringIndexOutOfBoundsException e) {
	    return -1;
	}
    }

    /**
     * Convert a MIME charset name into a valid Java charset name. <p>
     *
     * @param charset	the MIME charset name
     * @return  the Java charset equivalent. If a suitable mapping is
     *		not available, the passed in charset is itself returned.
     */
    public static String javaCharset(String charset) {
	if (mime2java == null || charset == null)
	    // no mapping table, or charset parameter is null
	    return charset;

	String alias =
	    (String)mime2java.get(charset.toLowerCase(Locale.ENGLISH));
	return alias == null ? charset : alias;
    }

    /**
     * Convert a java charset into its MIME charset name. <p>
     *
     * Note that a future version of JDK (post 1.2) might provide
     * this functionality, in which case, we may deprecate this
     * method then.
     *
     * @param   charset    the JDK charset
     * @return      	the MIME/IANA equivalent. If a mapping
     *			is not possible, the passed in charset itself
     *			is returned.
     * @since		JavaMail 1.1
     */
    public static String mimeCharset(String charset) {
	if (java2mime == null || charset == null) 
	    // no mapping table or charset param is null
	    return charset;

	String alias =
	    (String)java2mime.get(charset.toLowerCase(Locale.ENGLISH));
	return alias == null ? charset : alias;
    }

    private static String defaultJavaCharset;
    private static String defaultMIMECharset;

    /**
     * Get the default charset corresponding to the system's current 
     * default locale.  If the System property <code>mail.mime.charset</code>
     * is set, a system charset corresponding to this MIME charset will be
     * returned. <p>
     * 
     * @return	the default charset of the system's default locale, 
     * 		as a Java charset. (NOT a MIME charset)
     * @since	JavaMail 1.1
     */
    public static String getDefaultJavaCharset() {
	if (defaultJavaCharset == null) {
	    /*
	     * If mail.mime.charset is set, it controls the default
	     * Java charset as well.
	     */
	    String mimecs = null;
	    try {
		mimecs = System.getProperty("mail.mime.charset");
	    } catch (SecurityException ex) { }	// ignore it
	    if (mimecs != null && mimecs.length() > 0) {
		defaultJavaCharset = javaCharset(mimecs);
		return defaultJavaCharset;
	    }

	    try {
		defaultJavaCharset = System.getProperty("file.encoding", 
							"8859_1");
	    } catch (SecurityException sex) {
		
		class NullInputStream extends InputStream {
		    public int read() {
			return 0;
		    }
		}
		InputStreamReader reader = 
			new InputStreamReader(new NullInputStream());
		defaultJavaCharset = reader.getEncoding();
		if (defaultJavaCharset == null)
		    defaultJavaCharset = "8859_1";
	    }
	}