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Smack/source/org/jivesoftware/smack/util/StringUtils.java

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/**
* $RCSfile$
* $Revision$
* $Date$
*
* 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.logging.Level;
import java.util.logging.Logger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* A collection of utility methods for String objects.
*/
public class StringUtils {
private static Logger log = Logger.getLogger(StringUtils.class.getName());
/**
* 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 = "&quot;".toCharArray();
private static final char[] APOS_ENCODE = "&apos;".toCharArray();
private static final char[] AMP_ENCODE = "&amp;".toCharArray();
private static final char[] LT_ENCODE = "&lt;".toCharArray();
private static final char[] GT_ENCODE = "&gt;".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>&lt;space&gt;</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>&lt;</td><td>\3c</td></tr>
* <tr><td>&gt;</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 &lt;space&gt; 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>&lt;space&gt;</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>&lt;</td><td>\3c</td></tr>
* <tr><td>&gt;</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 &lt;space&gt; 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 &#235; (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) {
log.log(Level.SEVERE, "Failed to load the SHA-1 MessageDigest. Smack will be unable to function normally.", nsae);
}
}
// Now, compute hash.
try {
digest.update(data.getBytes("UTF-8"));
}
catch (UnsupportedEncodingException e) {
log.log(Level.SEVERE, "Error computing hash", 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) {
throw new IllegalStateException(uee);
}
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");
}
}
}
}
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