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Diffstat (limited to 'src/org/jivesoftware/smack/util/StringUtils.java')
| -rw-r--r-- | src/org/jivesoftware/smack/util/StringUtils.java | 800 |
1 files changed, 800 insertions, 0 deletions
diff --git a/src/org/jivesoftware/smack/util/StringUtils.java b/src/org/jivesoftware/smack/util/StringUtils.java new file mode 100644 index 0000000..7e3cfdc --- /dev/null +++ b/src/org/jivesoftware/smack/util/StringUtils.java @@ -0,0 +1,800 @@ +/** + * $RCSfile$ + * $Revision$ + * $Date$ + * + * Copyright 2003-2007 Jive Software. + * + * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.jivesoftware.smack.util; + +import java.io.UnsupportedEncodingException; +import java.security.MessageDigest; +import java.security.NoSuchAlgorithmException; +import java.text.DateFormat; +import java.text.ParseException; +import java.text.SimpleDateFormat; +import java.util.ArrayList; +import java.util.Calendar; +import java.util.Collections; +import java.util.Comparator; +import java.util.Date; +import java.util.List; +import java.util.Random; +import java.util.TimeZone; +import java.util.regex.Matcher; +import java.util.regex.Pattern; + +/** + * A collection of utility methods for String objects. + */ +public class StringUtils { + + /** + * Date format as defined in XEP-0082 - XMPP Date and Time Profiles. The time zone is set to + * UTC. + * <p> + * Date formats are not synchronized. Since multiple threads access the format concurrently, it + * must be synchronized externally or you can use the convenience methods + * {@link #parseXEP0082Date(String)} and {@link #formatXEP0082Date(Date)}. + * @deprecated This public version will be removed in favor of using the methods defined within this class. + */ + public static final DateFormat XEP_0082_UTC_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"); + + /* + * private version to use internally so we don't have to be concerned with thread safety. + */ + private static final DateFormat dateFormatter = DateFormatType.XEP_0082_DATE_PROFILE.createFormatter(); + private static final Pattern datePattern = Pattern.compile("^\\d+-\\d+-\\d+$"); + + private static final DateFormat timeFormatter = DateFormatType.XEP_0082_TIME_MILLIS_ZONE_PROFILE.createFormatter(); + private static final Pattern timePattern = Pattern.compile("^(\\d+:){2}\\d+.\\d+(Z|([+-](\\d+:\\d+)))$"); + private static final DateFormat timeNoZoneFormatter = DateFormatType.XEP_0082_TIME_MILLIS_PROFILE.createFormatter(); + private static final Pattern timeNoZonePattern = Pattern.compile("^(\\d+:){2}\\d+.\\d+$"); + + private static final DateFormat timeNoMillisFormatter = DateFormatType.XEP_0082_TIME_ZONE_PROFILE.createFormatter(); + private static final Pattern timeNoMillisPattern = Pattern.compile("^(\\d+:){2}\\d+(Z|([+-](\\d+:\\d+)))$"); + private static final DateFormat timeNoMillisNoZoneFormatter = DateFormatType.XEP_0082_TIME_PROFILE.createFormatter(); + private static final Pattern timeNoMillisNoZonePattern = Pattern.compile("^(\\d+:){2}\\d+$"); + + private static final DateFormat dateTimeFormatter = DateFormatType.XEP_0082_DATETIME_MILLIS_PROFILE.createFormatter(); + private static final Pattern dateTimePattern = Pattern.compile("^\\d+(-\\d+){2}+T(\\d+:){2}\\d+.\\d+(Z|([+-](\\d+:\\d+)))?$"); + private static final DateFormat dateTimeNoMillisFormatter = DateFormatType.XEP_0082_DATETIME_PROFILE.createFormatter(); + private static final Pattern dateTimeNoMillisPattern = Pattern.compile("^\\d+(-\\d+){2}+T(\\d+:){2}\\d+(Z|([+-](\\d+:\\d+)))?$"); + + private static final DateFormat xep0091Formatter = new SimpleDateFormat("yyyyMMdd'T'HH:mm:ss"); + private static final DateFormat xep0091Date6DigitFormatter = new SimpleDateFormat("yyyyMd'T'HH:mm:ss"); + private static final DateFormat xep0091Date7Digit1MonthFormatter = new SimpleDateFormat("yyyyMdd'T'HH:mm:ss"); + private static final DateFormat xep0091Date7Digit2MonthFormatter = new SimpleDateFormat("yyyyMMd'T'HH:mm:ss"); + private static final Pattern xep0091Pattern = Pattern.compile("^\\d+T\\d+:\\d+:\\d+$"); + + private static final List<PatternCouplings> couplings = new ArrayList<PatternCouplings>(); + + static { + TimeZone utc = TimeZone.getTimeZone("UTC"); + XEP_0082_UTC_FORMAT.setTimeZone(utc); + dateFormatter.setTimeZone(utc); + timeFormatter.setTimeZone(utc); + timeNoZoneFormatter.setTimeZone(utc); + timeNoMillisFormatter.setTimeZone(utc); + timeNoMillisNoZoneFormatter.setTimeZone(utc); + dateTimeFormatter.setTimeZone(utc); + dateTimeNoMillisFormatter.setTimeZone(utc); + + xep0091Formatter.setTimeZone(utc); + xep0091Date6DigitFormatter.setTimeZone(utc); + xep0091Date7Digit1MonthFormatter.setTimeZone(utc); + xep0091Date7Digit1MonthFormatter.setLenient(false); + xep0091Date7Digit2MonthFormatter.setTimeZone(utc); + xep0091Date7Digit2MonthFormatter.setLenient(false); + + couplings.add(new PatternCouplings(datePattern, dateFormatter)); + couplings.add(new PatternCouplings(dateTimePattern, dateTimeFormatter, true)); + couplings.add(new PatternCouplings(dateTimeNoMillisPattern, dateTimeNoMillisFormatter, true)); + couplings.add(new PatternCouplings(timePattern, timeFormatter, true)); + couplings.add(new PatternCouplings(timeNoZonePattern, timeNoZoneFormatter)); + couplings.add(new PatternCouplings(timeNoMillisPattern, timeNoMillisFormatter, true)); + couplings.add(new PatternCouplings(timeNoMillisNoZonePattern, timeNoMillisNoZoneFormatter)); + } + + private static final char[] QUOTE_ENCODE = """.toCharArray(); + private static final char[] APOS_ENCODE = "'".toCharArray(); + private static final char[] AMP_ENCODE = "&".toCharArray(); + private static final char[] LT_ENCODE = "<".toCharArray(); + private static final char[] GT_ENCODE = ">".toCharArray(); + + /** + * Parses the given date string in the <a href="http://xmpp.org/extensions/xep-0082.html">XEP-0082 - XMPP Date and Time Profiles</a>. + * + * @param dateString the date string to parse + * @return the parsed Date + * @throws ParseException if the specified string cannot be parsed + * @deprecated Use {@link #parseDate(String)} instead. + * + */ + public static Date parseXEP0082Date(String dateString) throws ParseException { + return parseDate(dateString); + } + + /** + * Parses the given date string in either of the three profiles of <a href="http://xmpp.org/extensions/xep-0082.html">XEP-0082 - XMPP Date and Time Profiles</a> + * or <a href="http://xmpp.org/extensions/xep-0091.html">XEP-0091 - Legacy Delayed Delivery</a> format. + * <p> + * This method uses internal date formatters and is thus threadsafe. + * @param dateString the date string to parse + * @return the parsed Date + * @throws ParseException if the specified string cannot be parsed + */ + public static Date parseDate(String dateString) throws ParseException { + Matcher matcher = xep0091Pattern.matcher(dateString); + + /* + * if date is in XEP-0091 format handle ambiguous dates missing the + * leading zero in month and day + */ + if (matcher.matches()) { + int length = dateString.split("T")[0].length(); + + if (length < 8) { + Date date = handleDateWithMissingLeadingZeros(dateString, length); + + if (date != null) + return date; + } + else { + synchronized (xep0091Formatter) { + return xep0091Formatter.parse(dateString); + } + } + } + else { + for (PatternCouplings coupling : couplings) { + matcher = coupling.pattern.matcher(dateString); + + if (matcher.matches()) + { + if (coupling.needToConvertTimeZone) { + dateString = coupling.convertTime(dateString); + } + + synchronized (coupling.formatter) { + return coupling.formatter.parse(dateString); + } + } + } + } + + /* + * We assume it is the XEP-0082 DateTime profile with no milliseconds at this point. If it isn't, is is just not parseable, then we attempt + * to parse it regardless and let it throw the ParseException. + */ + synchronized (dateTimeNoMillisFormatter) { + return dateTimeNoMillisFormatter.parse(dateString); + } + } + + /** + * Parses the given date string in different ways and returns the date that + * lies in the past and/or is nearest to the current date-time. + * + * @param stampString date in string representation + * @param dateLength + * @param noFuture + * @return the parsed date + * @throws ParseException The date string was of an unknown format + */ + private static Date handleDateWithMissingLeadingZeros(String stampString, int dateLength) throws ParseException { + if (dateLength == 6) { + synchronized (xep0091Date6DigitFormatter) { + return xep0091Date6DigitFormatter.parse(stampString); + } + } + Calendar now = Calendar.getInstance(); + + Calendar oneDigitMonth = parseXEP91Date(stampString, xep0091Date7Digit1MonthFormatter); + Calendar twoDigitMonth = parseXEP91Date(stampString, xep0091Date7Digit2MonthFormatter); + + List<Calendar> dates = filterDatesBefore(now, oneDigitMonth, twoDigitMonth); + + if (!dates.isEmpty()) { + return determineNearestDate(now, dates).getTime(); + } + return null; + } + + private static Calendar parseXEP91Date(String stampString, DateFormat dateFormat) { + try { + synchronized (dateFormat) { + dateFormat.parse(stampString); + return dateFormat.getCalendar(); + } + } + catch (ParseException e) { + return null; + } + } + + private static List<Calendar> filterDatesBefore(Calendar now, Calendar... dates) { + List<Calendar> result = new ArrayList<Calendar>(); + + for (Calendar calendar : dates) { + if (calendar != null && calendar.before(now)) { + result.add(calendar); + } + } + + return result; + } + + private static Calendar determineNearestDate(final Calendar now, List<Calendar> dates) { + + Collections.sort(dates, new Comparator<Calendar>() { + + public int compare(Calendar o1, Calendar o2) { + Long diff1 = new Long(now.getTimeInMillis() - o1.getTimeInMillis()); + Long diff2 = new Long(now.getTimeInMillis() - o2.getTimeInMillis()); + return diff1.compareTo(diff2); + } + + }); + + return dates.get(0); + } + + /** + * Formats a Date into a XEP-0082 - XMPP Date and Time Profiles string. + * + * @param date the time value to be formatted into a time string + * @return the formatted time string in XEP-0082 format + */ + public static String formatXEP0082Date(Date date) { + synchronized (dateTimeFormatter) { + return dateTimeFormatter.format(date); + } + } + + public static String formatDate(Date toFormat, DateFormatType type) + { + return null; + } + + /** + * Returns the name portion of a XMPP address. For example, for the + * address "matt@jivesoftware.com/Smack", "matt" would be returned. If no + * username is present in the address, the empty string will be returned. + * + * @param XMPPAddress the XMPP address. + * @return the name portion of the XMPP address. + */ + public static String parseName(String XMPPAddress) { + if (XMPPAddress == null) { + return null; + } + int atIndex = XMPPAddress.lastIndexOf("@"); + if (atIndex <= 0) { + return ""; + } + else { + return XMPPAddress.substring(0, atIndex); + } + } + + /** + * Returns the server portion of a XMPP address. For example, for the + * address "matt@jivesoftware.com/Smack", "jivesoftware.com" would be returned. + * If no server is present in the address, the empty string will be returned. + * + * @param XMPPAddress the XMPP address. + * @return the server portion of the XMPP address. + */ + public static String parseServer(String XMPPAddress) { + if (XMPPAddress == null) { + return null; + } + int atIndex = XMPPAddress.lastIndexOf("@"); + // If the String ends with '@', return the empty string. + if (atIndex + 1 > XMPPAddress.length()) { + return ""; + } + int slashIndex = XMPPAddress.indexOf("/"); + if (slashIndex > 0 && slashIndex > atIndex) { + return XMPPAddress.substring(atIndex + 1, slashIndex); + } + else { + return XMPPAddress.substring(atIndex + 1); + } + } + + /** + * Returns the resource portion of a XMPP address. For example, for the + * address "matt@jivesoftware.com/Smack", "Smack" would be returned. If no + * resource is present in the address, the empty string will be returned. + * + * @param XMPPAddress the XMPP address. + * @return the resource portion of the XMPP address. + */ + public static String parseResource(String XMPPAddress) { + if (XMPPAddress == null) { + return null; + } + int slashIndex = XMPPAddress.indexOf("/"); + if (slashIndex + 1 > XMPPAddress.length() || slashIndex < 0) { + return ""; + } + else { + return XMPPAddress.substring(slashIndex + 1); + } + } + + /** + * Returns the XMPP address with any resource information removed. For example, + * for the address "matt@jivesoftware.com/Smack", "matt@jivesoftware.com" would + * be returned. + * + * @param XMPPAddress the XMPP address. + * @return the bare XMPP address without resource information. + */ + public static String parseBareAddress(String XMPPAddress) { + if (XMPPAddress == null) { + return null; + } + int slashIndex = XMPPAddress.indexOf("/"); + if (slashIndex < 0) { + return XMPPAddress; + } + else if (slashIndex == 0) { + return ""; + } + else { + return XMPPAddress.substring(0, slashIndex); + } + } + + /** + * Returns true if jid is a full JID (i.e. a JID with resource part). + * + * @param jid + * @return true if full JID, false otherwise + */ + public static boolean isFullJID(String jid) { + if (parseName(jid).length() <= 0 || parseServer(jid).length() <= 0 + || parseResource(jid).length() <= 0) { + return false; + } + return true; + } + + /** + * Escapes the node portion of a JID according to "JID Escaping" (JEP-0106). + * Escaping replaces characters prohibited by node-prep with escape sequences, + * as follows:<p> + * + * <table border="1"> + * <tr><td><b>Unescaped Character</b></td><td><b>Encoded Sequence</b></td></tr> + * <tr><td><space></td><td>\20</td></tr> + * <tr><td>"</td><td>\22</td></tr> + * <tr><td>&</td><td>\26</td></tr> + * <tr><td>'</td><td>\27</td></tr> + * <tr><td>/</td><td>\2f</td></tr> + * <tr><td>:</td><td>\3a</td></tr> + * <tr><td><</td><td>\3c</td></tr> + * <tr><td>></td><td>\3e</td></tr> + * <tr><td>@</td><td>\40</td></tr> + * <tr><td>\</td><td>\5c</td></tr> + * </table><p> + * + * This process is useful when the node comes from an external source that doesn't + * conform to nodeprep. For example, a username in LDAP may be "Joe Smith". Because + * the <space> character isn't a valid part of a node, the username should + * be escaped to "Joe\20Smith" before being made into a JID (e.g. "joe\20smith@example.com" + * after case-folding, etc. has been applied).<p> + * + * All node escaping and un-escaping must be performed manually at the appropriate + * time; the JID class will not escape or un-escape automatically. + * + * @param node the node. + * @return the escaped version of the node. + */ + public static String escapeNode(String node) { + if (node == null) { + return null; + } + StringBuilder buf = new StringBuilder(node.length() + 8); + for (int i=0, n=node.length(); i<n; i++) { + char c = node.charAt(i); + switch (c) { + case '"': buf.append("\\22"); break; + case '&': buf.append("\\26"); break; + case '\'': buf.append("\\27"); break; + case '/': buf.append("\\2f"); break; + case ':': buf.append("\\3a"); break; + case '<': buf.append("\\3c"); break; + case '>': buf.append("\\3e"); break; + case '@': buf.append("\\40"); break; + case '\\': buf.append("\\5c"); break; + default: { + if (Character.isWhitespace(c)) { + buf.append("\\20"); + } + else { + buf.append(c); + } + } + } + } + return buf.toString(); + } + + /** + * Un-escapes the node portion of a JID according to "JID Escaping" (JEP-0106).<p> + * Escaping replaces characters prohibited by node-prep with escape sequences, + * as follows:<p> + * + * <table border="1"> + * <tr><td><b>Unescaped Character</b></td><td><b>Encoded Sequence</b></td></tr> + * <tr><td><space></td><td>\20</td></tr> + * <tr><td>"</td><td>\22</td></tr> + * <tr><td>&</td><td>\26</td></tr> + * <tr><td>'</td><td>\27</td></tr> + * <tr><td>/</td><td>\2f</td></tr> + * <tr><td>:</td><td>\3a</td></tr> + * <tr><td><</td><td>\3c</td></tr> + * <tr><td>></td><td>\3e</td></tr> + * <tr><td>@</td><td>\40</td></tr> + * <tr><td>\</td><td>\5c</td></tr> + * </table><p> + * + * This process is useful when the node comes from an external source that doesn't + * conform to nodeprep. For example, a username in LDAP may be "Joe Smith". Because + * the <space> character isn't a valid part of a node, the username should + * be escaped to "Joe\20Smith" before being made into a JID (e.g. "joe\20smith@example.com" + * after case-folding, etc. has been applied).<p> + * + * All node escaping and un-escaping must be performed manually at the appropriate + * time; the JID class will not escape or un-escape automatically. + * + * @param node the escaped version of the node. + * @return the un-escaped version of the node. + */ + public static String unescapeNode(String node) { + if (node == null) { + return null; + } + char [] nodeChars = node.toCharArray(); + StringBuilder buf = new StringBuilder(nodeChars.length); + for (int i=0, n=nodeChars.length; i<n; i++) { + compare: { + char c = node.charAt(i); + if (c == '\\' && i+2<n) { + char c2 = nodeChars[i+1]; + char c3 = nodeChars[i+2]; + if (c2 == '2') { + switch (c3) { + case '0': buf.append(' '); i+=2; break compare; + case '2': buf.append('"'); i+=2; break compare; + case '6': buf.append('&'); i+=2; break compare; + case '7': buf.append('\''); i+=2; break compare; + case 'f': buf.append('/'); i+=2; break compare; + } + } + else if (c2 == '3') { + switch (c3) { + case 'a': buf.append(':'); i+=2; break compare; + case 'c': buf.append('<'); i+=2; break compare; + case 'e': buf.append('>'); i+=2; break compare; + } + } + else if (c2 == '4') { + if (c3 == '0') { + buf.append("@"); + i+=2; + break compare; + } + } + else if (c2 == '5') { + if (c3 == 'c') { + buf.append("\\"); + i+=2; + break compare; + } + } + } + buf.append(c); + } + } + return buf.toString(); + } + + /** + * 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 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; + StringBuilder out = new StringBuilder((int)(len*1.3)); + for (; i < len; i++) { + ch = input[i]; + if (ch > '>') { + } + 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(GT_ENCODE); + } + + else if (ch == '&') { + if (i > last) { + out.append(input, last, i - last); + } + // Do nothing if the string is of the form ë (unicode value) + if (!(len > i + 5 + && input[i + 1] == '#' + && Character.isDigit(input[i + 2]) + && Character.isDigit(input[i + 3]) + && Character.isDigit(input[i + 4]) + && input[i + 5] == ';')) { + 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(APOS_ENCODE); + } + } + if (last == 0) { + return string; + } + if (i > last) { + out.append(input, last, i - last); + } + return out.toString(); + } + + /** + * Used by the hash method. + */ + private static MessageDigest digest = null; + + /** + * Hashes a String using the SHA-1 algorithm and returns the result as a + * String of hexadecimal numbers. This method is synchronized to avoid + * excessive MessageDigest object creation. If calling this method becomes + * a bottleneck in your code, you may wish to maintain a pool of + * MessageDigest objects instead of using this method. + * <p> + * A hash is a one-way function -- that is, given an + * input, an output is easily computed. However, given the output, the + * input is almost impossible to compute. This is useful for passwords + * since we can store the hash and a hacker will then have a very hard time + * determining the original password. + * + * @param data the String to compute the hash of. + * @return a hashed version of the passed-in String + */ + public synchronized static String hash(String data) { + if (digest == null) { + try { + digest = MessageDigest.getInstance("SHA-1"); + } + catch (NoSuchAlgorithmException nsae) { + System.err.println("Failed to load the SHA-1 MessageDigest. " + + "Jive will be unable to function normally."); + } + } + // Now, compute hash. + try { + digest.update(data.getBytes("UTF-8")); + } + catch (UnsupportedEncodingException e) { + System.err.println(e); + } + return encodeHex(digest.digest()); + } + + /** + * Encodes an array of bytes as String representation of hexadecimal. + * + * @param bytes an array of bytes to convert to a hex string. + * @return generated hex string. + */ + public static String encodeHex(byte[] bytes) { + StringBuilder hex = new StringBuilder(bytes.length * 2); + + for (byte aByte : bytes) { + if (((int) aByte & 0xff) < 0x10) { + hex.append("0"); + } + hex.append(Integer.toString((int) aByte & 0xff, 16)); + } + + return hex.toString(); + } + + /** + * Encodes a String as a base64 String. + * + * @param data a String to encode. + * @return a base64 encoded String. + */ + public static String encodeBase64(String data) { + byte [] bytes = null; + try { + bytes = data.getBytes("ISO-8859-1"); + } + catch (UnsupportedEncodingException uee) { + uee.printStackTrace(); + } + return encodeBase64(bytes); + } + + /** + * Encodes a byte array into a base64 String. + * + * @param data a byte array to encode. + * @return a base64 encode String. + */ + public static String encodeBase64(byte[] data) { + return encodeBase64(data, false); + } + + /** + * Encodes a byte array into a bse64 String. + * + * @param data The byte arry to encode. + * @param lineBreaks True if the encoding should contain line breaks and false if it should not. + * @return A base64 encoded String. + */ + public static String encodeBase64(byte[] data, boolean lineBreaks) { + return encodeBase64(data, 0, data.length, lineBreaks); + } + + /** + * Encodes a byte array into a bse64 String. + * + * @param data The byte arry to encode. + * @param offset the offset of the bytearray to begin encoding at. + * @param len the length of bytes to encode. + * @param lineBreaks True if the encoding should contain line breaks and false if it should not. + * @return A base64 encoded String. + */ + public static String encodeBase64(byte[] data, int offset, int len, boolean lineBreaks) { + return Base64.encodeBytes(data, offset, len, (lineBreaks ? Base64.NO_OPTIONS : Base64.DONT_BREAK_LINES)); + } + + /** + * Decodes a base64 String. + * Unlike Base64.decode() this method does not try to detect and decompress a gzip-compressed input. + * + * @param data a base64 encoded String to decode. + * @return the decoded String. + */ + public static byte[] decodeBase64(String data) { + byte[] bytes; + try { + bytes = data.getBytes("UTF-8"); + } catch (java.io.UnsupportedEncodingException uee) { + bytes = data.getBytes(); + } + + bytes = Base64.decode(bytes, 0, bytes.length, Base64.NO_OPTIONS); + return bytes; + } + + /** + * 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 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); + } + + private StringUtils() { + // Not instantiable. + } + + private static class PatternCouplings { + Pattern pattern; + DateFormat formatter; + boolean needToConvertTimeZone = false; + + public PatternCouplings(Pattern datePattern, DateFormat dateFormat) { + pattern = datePattern; + formatter = dateFormat; + } + + public PatternCouplings(Pattern datePattern, DateFormat dateFormat, boolean shouldConvertToRFC822) { + pattern = datePattern; + formatter = dateFormat; + needToConvertTimeZone = shouldConvertToRFC822; + } + + public String convertTime(String dateString) { + if (dateString.charAt(dateString.length() - 1) == 'Z') { + return dateString.replace("Z", "+0000"); + } + else { + // If the time zone wasn't specified with 'Z', then it's in + // ISO8601 format (i.e. '(+|-)HH:mm') + // RFC822 needs a similar format just without the colon (i.e. + // '(+|-)HHmm)'), so remove it + return dateString.replaceAll("([\\+\\-]\\d\\d):(\\d\\d)","$1$2"); + } + } + } + +} |