util.java

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		return encodeHex(digest.digest());
	}

	/**
	 * Turns an array of bytes into a String representing each byte as an
	 * unsigned hex number.
	 * <p>
	 * Method by Santeri Paavolainen, Helsinki Finland 1996<br>
	 * (c) Santeri Paavolainen, Helsinki Finland 1996<br>
	 * Distributed under LGPL.
	 *
	 * @param bytes
	 *            an array of bytes to convert to a hex-string
	 * @return generated hex string
	 */
	public static final String encodeHex(byte[] bytes) {
		StringBuffer buf = new StringBuffer(bytes.length * 2);
		int i;

		for (i = 0; i < bytes.length; i++) {
			if (((int) bytes[i] & 0xff) < 0x10) {
				buf.append("0");
			}
			buf.append(Long.toString((int) bytes[i] & 0xff, 16));
		}
		return buf.toString().toUpperCase();
	}

	/**
	 * Turns a hex encoded string into a byte array. It is specifically meant to
	 * "reverse" the toHex(byte[]) method.
	 *
	 * @param hex
	 *            a hex encoded String to transform into a byte array.
	 * @return a byte array representing the hex String[
	 */
	public static final byte[] decodeHex(String hex) {
		char[] chars = hex.toCharArray();
		byte[] bytes = new byte[chars.length / 2];
		int byteCount = 0;
		for (int i = 0; i < chars.length; i += 2) {
			byte newByte = 0x00;
			newByte |= hexCharToByte(chars[i]);
			newByte <<= 4;
			newByte |= hexCharToByte(chars[i + 1]);
			bytes[byteCount] = newByte;
			byteCount++;
		}
		return bytes;
	}

	/**
	 * Returns the the byte value of a hexadecmical char (0-f). It's assumed
	 * that the hexidecimal chars are lower case as appropriate.
	 *
	 * @param ch
	 *            a hexedicmal character (0-f)
	 * @return the byte value of the character (0x00-0x0F)
	 */
	private static final byte hexCharToByte(char ch) {
		switch (ch) {
		case '0':
			return 0x00;
		case '1':
			return 0x01;
		case '2':
			return 0x02;
		case '3':
			return 0x03;
		case '4':
			return 0x04;
		case '5':
			return 0x05;
		case '6':
			return 0x06;
		case '7':
			return 0x07;
		case '8':
			return 0x08;
		case '9':
			return 0x09;
		case 'a':
			return 0x0A;
		case 'b':
			return 0x0B;
		case 'c':
			return 0x0C;
		case 'd':
			return 0x0D;
		case 'e':
			return 0x0E;
		case 'f':
			return 0x0F;
		}
		return 0x00;
	}

	/**
	 * Converts a line of text into an array of lower case words using a
	 * BreakIterator.wordInstance().
	 * <p>
	 *
	 * This method is under the Jive Open Source Software License and was
	 * written by Mark Imbriaco.
	 *
	 * @param text
	 *            a String of text to convert into an array of words
	 * @return text broken up into an array of words.
	 */
	public static final String[] toLowerCaseWordArray(String text) {
		if (text == null || text.length() == 0) {
			return new String[0];
		}

		ArrayList<String> wordList = new ArrayList<String>();
		BreakIterator boundary = BreakIterator.getWordInstance();
		boundary.setText(text);
		int start = 0;

		for (int end = boundary.next(); end != BreakIterator.DONE; start = end, end = boundary.next()) {
			String tmp = text.substring(start, end).trim();
			// Remove characters that are not needed.
			tmp = replace(tmp, "+", "");
			tmp = replace(tmp, "/", "");
			tmp = replace(tmp, "\\", "");
			tmp = replace(tmp, "#", "");
			tmp = replace(tmp, "*", "");
			tmp = replace(tmp, ")", "");
			tmp = replace(tmp, "(", "");
			tmp = replace(tmp, "&", "");
			if (tmp.length() > 0) {
				wordList.add(tmp);
			}
		}
		return (String[]) wordList.toArray(new String[wordList.size()]);
	}

	/**
	 * Pseudo-random number generator object for use with randomString(). The
	 * Random class is not considered to be cryptographically secure, so only
	 * use these random Strings for low to medium security applications.
	 */
	private static Random randGen = new Random();

	/**
	 * Array of numbers and letters of mixed case. Numbers appear in the list
	 * twice so that there is a more equal chance that a number will be picked.
	 * We can use the array to get a random number or letter by picking a random
	 * array index.
	 */
	private static char[] numbersAndLetters = ("0123456789abcdefghijklmnopqrstuvwxyz"
			+ "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();

	/**
	 * Returns a random String of numbers and letters (lower and upper case) of
	 * the specified length. The method uses the Random class that is built-in
	 * to Java which is suitable for low to medium grade security uses. This
	 * means that the output is only pseudo random, i.e., each number is
	 * mathematically generated so is not truly random.
	 * <p>
	 *
	 * The specified length must be at least one. If not, the method will return
	 * null.
	 *
	 * @param length
	 *            the desired length of the random String to return.
	 * @return a random String of numbers and letters of the specified length.
	 */
	public static final String randomString(int length) {
		if (length < 1) {
			return null;
		}
		// Create a char buffer to put random letters and numbers in.
		char[] randBuffer = new char[length];
		for (int i = 0; i < randBuffer.length; i++) {
			randBuffer[i] = numbersAndLetters[randGen.nextInt(71)];
		}
		return new String(randBuffer);
	}

	/**
	 * Intelligently chops a String at a word boundary (whitespace) that occurs
	 * at the specified index in the argument or before. However, if there is a
	 * newline character before <code>length</code>, the String will be
	 * chopped there. If no newline or whitespace is found in
	 * <code>string</code> up to the index <code>length</code>, the String
	 * will chopped at <code>length</code>.
	 * <p>
	 * For example, chopAtWord("This is a nice String", 10) will return "This is
	 * a" which is the first word boundary less than or equal to 10 characters
	 * into the original String.
	 *
	 * @param string
	 *            the String to chop.
	 * @param length
	 *            the index in <code>string</code> to start looking for a
	 *            whitespace boundary at.
	 * @return a substring of <code>string</code> whose length is less than or
	 *         equal to <code>length</code>, and that is chopped at
	 *         whitespace.
	 */
	public static final String chopAtWord(String string, int length) {
		if (string == null) {
			return string;
		}

		char[] charArray = string.toCharArray();
		int sLength = string.length();
		if (length < sLength) {
			sLength = length;
		}

		// First check if there is a newline character before length; if so,
		// chop word there.
		for (int i = 0; i < sLength - 1; i++) {
			// Windows
			if (charArray[i] == '\r' && charArray[i + 1] == '\n') {
				return string.substring(0, i + 1);
			}
			// Unix
			else if (charArray[i] == '\n') {
				return string.substring(0, i);
			}
		}
		// Also check boundary case of Unix newline
		if (charArray[sLength - 1] == '\n') {
			return string.substring(0, sLength - 1);
		}

		// Done checking for newline, now see if the total string is less than
		// the specified chop point.
		if (string.length() < length) {
			return string;
		}

		// No newline, so chop at the first whitespace.
		for (int i = length - 1; i > 0; i--) {
			if (charArray[i] == ' ') {
				return string.substring(0, i).trim();
			}
		}

		// Did not find word boundary so return original String chopped at
		// specified length.
		return string.substring(0, length);
	}

	/**
	 * Escapes all necessary characters in the String so that it can be used in
	 * an XML doc.
	 *
	 * @param string
	 *            the string to escape.
	 * @return the string with appropriate characters escaped.
	 */
	public static final String escapeForXML(String string) {
		if (string == null) {
			return null;
		}
		char ch;
		int i = 0;
		int last = 0;
		char[] input = string.toCharArray();
		int len = input.length;
		StringBuffer out = new StringBuffer((int) (len * 1.3));
		for (; i < len; i++) {
			ch = input[i];
			if (ch > '>') {
				continue;
			} else if (ch == '<') {
				if (i > last) {
					out.append(input, last, i - last);
				}
				last = i + 1;
				out.append(LT_ENCODE);
			} else if (ch == '&') {
				if (i > last) {
					out.append(input, last, i - last);
				}
				last = i + 1;
				out.append(AMP_ENCODE);
			} else if (ch == '"') {
				if (i > last) {
					out.append(input, last, i - last);
				}
				last = i + 1;
				out.append(QUOTE_ENCODE);
			}
		}
		if (last == 0) {
			return string;
		}
		if (i > last) {
			out.append(input, last, i - last);
		}
		return out.toString();
	}

	public static final String escapeForSpecial(String string) {
		if (string == null) {
			return null;
		}
		char ch;
		int i = 0;
		int last = 0;
		char[] input = string.toCharArray();
		int len = input.length;
		StringBuffer out = new StringBuffer((int) (len * 1.3));
		for (; i < len; i++) {
			ch = input[i];
			if (ch > '>') {
				continue;
			} else if (ch == '<') {
				if (i > last) {
					out.append(input, last, i - last);
				}
				last = i + 1;
				out.append(LT_ENCODE);
			} else if (ch == '&') {
				if (i > last) {
					out.append(input, last, i - last);
				}
				last = i + 1;
				out.append(AMP_ENCODE);
			} else if (ch == '"') {
				if (i > last) {
					out.append(input, last, i - last);
				}
				last = i + 1;
				out.append(QUOTE_ENCODE);
			} else if (ch == '>') {
				if (i > last) {
					out.append(input, last, i - last);
				}
				last = i + 1;
				out.append(GT_ENCODE);
			}
		}
		if (last == 0) {
			return string;
		}
		if (i > last) {
			out.append(input, last, i - last);
		}
		return out.toString();
	}

	/**
	 * Unescapes the String by converting XML escape sequences back into normal
	 * characters.
	 *
	 * @param string
	 *            the string to unescape.
	 * @return the string with appropriate characters unescaped.
	 */
	public static final String unescapeFromXML(String string) {
		string = replace(string, "&lt;", "<");
		string = replace(string, "&gt;", ">");
		string = replace(string, "&quot;", "\"");
		return replace(string, "&amp;", "&");