Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.apache.hive.common.util; import java.io.PrintWriter; import java.io.StringWriter; import java.net.InetAddress; import java.net.URI; import java.net.URISyntaxException; import java.net.UnknownHostException; import java.text.DateFormat; import java.text.DecimalFormat; import java.text.NumberFormat; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Date; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.HashMap; import java.util.Locale; import java.util.Properties; import java.util.StringTokenizer; import java.util.regex.Pattern; import com.google.common.collect.Interner; import com.google.common.collect.Interners; import org.apache.commons.lang.StringUtils; import org.apache.commons.lang3.text.translate.CharSequenceTranslator; import org.apache.commons.lang3.text.translate.EntityArrays; import org.apache.commons.lang3.text.translate.LookupTranslator; import org.apache.hadoop.fs.Path; import org.apache.hadoop.hive.common.classification.InterfaceAudience; import org.apache.hadoop.hive.common.classification.InterfaceStability; import org.apache.hadoop.io.Text; /** * HiveStringUtils * General string utils * * Originally copied from o.a.hadoop.util.StringUtils */ @InterfaceAudience.Private @InterfaceStability.Unstable public class HiveStringUtils { /** * Priority of the StringUtils shutdown hook. */ public static final int SHUTDOWN_HOOK_PRIORITY = 0; private static final DecimalFormat decimalFormat; private static final CharSequenceTranslator ESCAPE_JAVA = new LookupTranslator( new String[][] { { "\"", "\\\"" }, { "\\", "\\\\" }, }) .with(new LookupTranslator(EntityArrays.JAVA_CTRL_CHARS_ESCAPE())); /** * Maintain a String pool to reduce memory. */ private static final Interner<String> STRING_INTERNER; static { NumberFormat numberFormat = NumberFormat.getNumberInstance(Locale.ENGLISH); decimalFormat = (DecimalFormat) numberFormat; decimalFormat.applyPattern("#.##"); STRING_INTERNER = Interners.newWeakInterner(); } /** * Return the internalized string, or null if the given string is null. * @param str The string to intern * @return The identical string cached in the string pool. */ public static String intern(String str) { if (str == null) { return null; } return STRING_INTERNER.intern(str); } /** * Return an interned list with identical contents as the given list. * @param list The list whose strings will be interned * @return An identical list with its strings interned. */ public static List<String> intern(List<String> list) { if (list == null) { return null; } List<String> newList = new ArrayList<String>(list.size()); for (String str : list) { newList.add(intern(str)); } return newList; } /** * Return an interned map with identical contents as the given map. * @param map The map whose strings will be interned * @return An identical map with its strings interned. */ public static Map<String, String> intern(Map<String, String> map) { if (map == null) { return null; } Map<String, String> newMap = new HashMap<String, String>(map.size()); for (Map.Entry<String, String> entry : map.entrySet()) { newMap.put(intern(entry.getKey()), intern(entry.getValue())); } return newMap; } /** * Make a string representation of the exception. * @param e The exception to stringify * @return A string with exception name and call stack. */ public static String stringifyException(Throwable e) { StringWriter stm = new StringWriter(); PrintWriter wrt = new PrintWriter(stm); e.printStackTrace(wrt); wrt.close(); return stm.toString(); } /** * Given a full hostname, return the word upto the first dot. * @param fullHostname the full hostname * @return the hostname to the first dot */ public static String simpleHostname(String fullHostname) { int offset = fullHostname.indexOf('.'); if (offset != -1) { return fullHostname.substring(0, offset); } return fullHostname; } private static DecimalFormat oneDecimal = new DecimalFormat("0.0"); /** * Given an integer, return a string that is in an approximate, but human * readable format. * It uses the bases 'k', 'm', and 'g' for 1024, 1024**2, and 1024**3. * @param number the number to format * @return a human readable form of the integer */ public static String humanReadableInt(long number) { long absNumber = Math.abs(number); double result = number; String suffix = ""; if (absNumber < 1024) { // since no division has occurred, don't format with a decimal point return String.valueOf(number); } else if (absNumber < 1024 * 1024) { result = number / 1024.0; suffix = "k"; } else if (absNumber < 1024 * 1024 * 1024) { result = number / (1024.0 * 1024); suffix = "m"; } else { result = number / (1024.0 * 1024 * 1024); suffix = "g"; } return oneDecimal.format(result) + suffix; } /** * Format a percentage for presentation to the user. * @param done the percentage to format (0.0 to 1.0) * @param digits the number of digits past the decimal point * @return a string representation of the percentage */ public static String formatPercent(double done, int digits) { DecimalFormat percentFormat = new DecimalFormat("0.00%"); double scale = Math.pow(10.0, digits + 2); double rounded = Math.floor(done * scale); percentFormat.setDecimalSeparatorAlwaysShown(false); percentFormat.setMinimumFractionDigits(digits); percentFormat.setMaximumFractionDigits(digits); return percentFormat.format(rounded / scale); } /** * Given an array of strings, return a comma-separated list of its elements. * @param strs Array of strings * @return Empty string if strs.length is 0, comma separated list of strings * otherwise */ public static String arrayToString(String[] strs) { if (strs.length == 0) { return ""; } StringBuilder sbuf = new StringBuilder(); sbuf.append(strs[0]); for (int idx = 1; idx < strs.length; idx++) { sbuf.append(","); sbuf.append(strs[idx]); } return sbuf.toString(); } /** * Given an array of bytes it will convert the bytes to a hex string * representation of the bytes * @param bytes * @param start start index, inclusively * @param end end index, exclusively * @return hex string representation of the byte array */ public static String byteToHexString(byte[] bytes, int start, int end) { if (bytes == null) { throw new IllegalArgumentException("bytes == null"); } StringBuilder s = new StringBuilder(); for (int i = start; i < end; i++) { s.append(String.format("%02x", bytes[i])); } return s.toString(); } /** Same as byteToHexString(bytes, 0, bytes.length). */ public static String byteToHexString(byte bytes[]) { return byteToHexString(bytes, 0, bytes.length); } /** * Given a hexstring this will return the byte array corresponding to the * string * @param hex the hex String array * @return a byte array that is a hex string representation of the given * string. The size of the byte array is therefore hex.length/2 */ public static byte[] hexStringToByte(String hex) { byte[] bts = new byte[hex.length() / 2]; for (int i = 0; i < bts.length; i++) { bts[i] = (byte) Integer.parseInt(hex.substring(2 * i, 2 * i + 2), 16); } return bts; } /** * * @param uris */ public static String uriToString(URI[] uris) { if (uris == null) { return null; } StringBuilder ret = new StringBuilder(uris[0].toString()); for (int i = 1; i < uris.length; i++) { ret.append(","); ret.append(uris[i].toString()); } return ret.toString(); } /** * @param str * The string array to be parsed into an URI array. * @return <tt>null</tt> if str is <tt>null</tt>, else the URI array * equivalent to str. * @throws IllegalArgumentException * If any string in str violates RFC 2396. */ public static URI[] stringToURI(String[] str) { if (str == null) { return null; } URI[] uris = new URI[str.length]; for (int i = 0; i < str.length; i++) { try { uris[i] = new URI(str[i]); } catch (URISyntaxException ur) { throw new IllegalArgumentException("Failed to create uri for " + str[i], ur); } } return uris; } /** * * @param str */ public static Path[] stringToPath(String[] str) { if (str == null) { return null; } Path[] p = new Path[str.length]; for (int i = 0; i < str.length; i++) { p[i] = new Path(str[i]); } return p; } /** * * Given a finish and start time in long milliseconds, returns a * String in the format Xhrs, Ymins, Z sec, for the time difference between two times. * If finish time comes before start time then negative valeus of X, Y and Z wil return. * * @param finishTime finish time * @param startTime start time */ public static String formatTimeDiff(long finishTime, long startTime) { long timeDiff = finishTime - startTime; return formatTime(timeDiff); } /** * * Given the time in long milliseconds, returns a * String in the format Xhrs, Ymins, Z sec. * * @param timeDiff The time difference to format */ public static String formatTime(long timeDiff) { StringBuilder buf = new StringBuilder(); long hours = timeDiff / (60 * 60 * 1000); long rem = (timeDiff % (60 * 60 * 1000)); long minutes = rem / (60 * 1000); rem = rem % (60 * 1000); long seconds = rem / 1000; if (hours != 0) { buf.append(hours); buf.append("hrs, "); } if (minutes != 0) { buf.append(minutes); buf.append("mins, "); } // return "0sec if no difference buf.append(seconds); buf.append("sec"); return buf.toString(); } /** * Formats time in ms and appends difference (finishTime - startTime) * as returned by formatTimeDiff(). * If finish time is 0, empty string is returned, if start time is 0 * then difference is not appended to return value. * @param dateFormat date format to use * @param finishTime fnish time * @param startTime start time * @return formatted value. */ public static String getFormattedTimeWithDiff(DateFormat dateFormat, long finishTime, long startTime) { StringBuilder buf = new StringBuilder(); if (0 != finishTime) { buf.append(dateFormat.format(new Date(finishTime))); if (0 != startTime) { buf.append(" (" + formatTimeDiff(finishTime, startTime) + ")"); } } return buf.toString(); } /** * Returns an arraylist of strings. * @param str the comma seperated string values * @return the arraylist of the comma seperated string values */ public static String[] getStrings(String str) { Collection<String> values = getStringCollection(str); if (values.size() == 0) { return null; } return values.toArray(new String[values.size()]); } /** * Returns a collection of strings. * @param str comma seperated string values * @return an <code>ArrayList</code> of string values */ public static Collection<String> getStringCollection(String str) { List<String> values = new ArrayList<String>(); if (str == null) { return values; } StringTokenizer tokenizer = new StringTokenizer(str, ","); values = new ArrayList<String>(); while (tokenizer.hasMoreTokens()) { values.add(tokenizer.nextToken()); } return values; } /** * Splits a comma separated value <code>String</code>, trimming leading and trailing whitespace on each value. * @param str a comma separated <String> with values * @return a <code>Collection</code> of <code>String</code> values */ public static Collection<String> getTrimmedStringCollection(String str) { return new ArrayList<String>(Arrays.asList(getTrimmedStrings(str))); } /** * Splits a comma separated value <code>String</code>, trimming leading and trailing whitespace on each value. * @param str a comma separated <String> with values * @return an array of <code>String</code> values */ public static String[] getTrimmedStrings(String str) { if (null == str || "".equals(str.trim())) { return emptyStringArray; } return str.trim().split("\\s*,\\s*"); } final public static String[] emptyStringArray = {}; final public static char COMMA = ','; final public static String COMMA_STR = ","; final public static char ESCAPE_CHAR = '\\'; /** * Split a string using the default separator * @param str a string that may have escaped separator * @return an array of strings */ public static String[] split(String str) { return split(str, ESCAPE_CHAR, COMMA); } /** * Split a string using the given separator * @param str a string that may have escaped separator * @param escapeChar a char that be used to escape the separator * @param separator a separator char * @return an array of strings */ public static String[] split(String str, char escapeChar, char separator) { if (str == null) { return null; } ArrayList<String> strList = new ArrayList<String>(); StringBuilder split = new StringBuilder(); int index = 0; while ((index = findNext(str, separator, escapeChar, index, split)) >= 0) { ++index; // move over the separator for next search strList.add(split.toString()); split.setLength(0); // reset the buffer } strList.add(split.toString()); // remove trailing empty split(s) int last = strList.size(); // last split while (--last >= 0 && "".equals(strList.get(last))) { strList.remove(last); } return strList.toArray(new String[strList.size()]); } /** * Split a string using the given separator, with no escaping performed. * @param str a string to be split. Note that this may not be null. * @param separator a separator char * @return an array of strings */ public static String[] split(String str, char separator) { // String.split returns a single empty result for splitting the empty // string. if ("".equals(str)) { return new String[] { "" }; } ArrayList<String> strList = new ArrayList<String>(); int startIndex = 0; int nextIndex = 0; while ((nextIndex = str.indexOf((int) separator, startIndex)) != -1) { strList.add(str.substring(startIndex, nextIndex)); startIndex = nextIndex + 1; } strList.add(str.substring(startIndex)); // remove trailing empty split(s) int last = strList.size(); // last split while (--last >= 0 && "".equals(strList.get(last))) { strList.remove(last); } return strList.toArray(new String[strList.size()]); } /** * Split a string using the default separator/escape character, * then unescape the resulting array of strings * @param str * @return an array of unescaped strings */ public static String[] splitAndUnEscape(String str) { return splitAndUnEscape(str, ESCAPE_CHAR, COMMA); } /** * Split a string using the specified separator/escape character, * then unescape the resulting array of strings using the same escape/separator. * @param str a string that may have escaped separator * @param escapeChar a char that be used to escape the separator * @param separator a separator char * @return an array of unescaped strings */ public static String[] splitAndUnEscape(String str, char escapeChar, char separator) { String[] result = split(str, escapeChar, separator); if (result != null) { for (int idx = 0; idx < result.length; ++idx) { result[idx] = unEscapeString(result[idx], escapeChar, separator); } } return result; } /** * Finds the first occurrence of the separator character ignoring the escaped * separators starting from the index. Note the substring between the index * and the position of the separator is passed. * @param str the source string * @param separator the character to find * @param escapeChar character used to escape * @param start from where to search * @param split used to pass back the extracted string */ public static int findNext(String str, char separator, char escapeChar, int start, StringBuilder split) { int numPreEscapes = 0; for (int i = start; i < str.length(); i++) { char curChar = str.charAt(i); if (numPreEscapes == 0 && curChar == separator) { // separator return i; } else { split.append(curChar); numPreEscapes = (curChar == escapeChar) ? (++numPreEscapes) % 2 : 0; } } return -1; } /** * Escape commas in the string using the default escape char * @param str a string * @return an escaped string */ public static String escapeString(String str) { return escapeString(str, ESCAPE_CHAR, COMMA); } /** * Escape <code>charToEscape</code> in the string * with the escape char <code>escapeChar</code> * * @param str string * @param escapeChar escape char * @param charToEscape the char to be escaped * @return an escaped string */ public static String escapeString(String str, char escapeChar, char charToEscape) { return escapeString(str, escapeChar, new char[] { charToEscape }); } // check if the character array has the character private static boolean hasChar(char[] chars, char character) { for (char target : chars) { if (character == target) { return true; } } return false; } /** * @param charsToEscape array of characters to be escaped */ public static String escapeString(String str, char escapeChar, char[] charsToEscape) { if (str == null) { return null; } StringBuilder result = new StringBuilder(); for (int i = 0; i < str.length(); i++) { char curChar = str.charAt(i); if (curChar == escapeChar || hasChar(charsToEscape, curChar)) { // special char result.append(escapeChar); } result.append(curChar); } return result.toString(); } /** * Escape non-unicode characters. StringEscapeUtil.escapeJava() will escape * unicode characters as well but in some cases it's not desired. * * @param str Original string * @return Escaped string */ public static String escapeJava(String str) { return ESCAPE_JAVA.translate(str); } /** * Unescape commas in the string using the default escape char * @param str a string * @return an unescaped string */ public static String unEscapeString(String str) { return unEscapeString(str, ESCAPE_CHAR, COMMA); } /** * Unescape <code>charToEscape</code> in the string * with the escape char <code>escapeChar</code> * * @param str string * @param escapeChar escape char * @param charToEscape the escaped char * @return an unescaped string */ public static String unEscapeString(String str, char escapeChar, char charToEscape) { return unEscapeString(str, escapeChar, new char[] { charToEscape }); } /** * @param charsToEscape array of characters to unescape */ public static String unEscapeString(String str, char escapeChar, char[] charsToEscape) { if (str == null) { return null; } StringBuilder result = new StringBuilder(str.length()); boolean hasPreEscape = false; for (int i = 0; i < str.length(); i++) { char curChar = str.charAt(i); if (hasPreEscape) { if (curChar != escapeChar && !hasChar(charsToEscape, curChar)) { // no special char throw new IllegalArgumentException( "Illegal escaped string " + str + " unescaped " + escapeChar + " at " + (i - 1)); } // otherwise discard the escape char result.append(curChar); hasPreEscape = false; } else { if (hasChar(charsToEscape, curChar)) { throw new IllegalArgumentException( "Illegal escaped string " + str + " unescaped " + curChar + " at " + i); } else if (curChar == escapeChar) { hasPreEscape = true; } else { result.append(curChar); } } } if (hasPreEscape) { throw new IllegalArgumentException( "Illegal escaped string " + str + ", not expecting " + escapeChar + " in the end."); } return result.toString(); } /** * Return a message for logging. * @param prefix prefix keyword for the message * @param msg content of the message * @return a message for logging */ private static String toStartupShutdownString(String prefix, String[] msg) { StringBuilder b = new StringBuilder(prefix); b.append("\n/************************************************************"); for (String s : msg) { b.append("\n" + prefix + s); } b.append("\n************************************************************/"); return b.toString(); } /** * Print a log message for starting up and shutting down * @param clazz the class of the server * @param args arguments * @param LOG the target log object */ public static void startupShutdownMessage(Class<?> clazz, String[] args, final org.slf4j.Logger LOG) { final String hostname = getHostname(); final String classname = clazz.getSimpleName(); LOG.info(toStartupShutdownString("STARTUP_MSG: ", new String[] { "Starting " + classname, " host = " + hostname, " args = " + Arrays.asList(args), " version = " + HiveVersionInfo.getVersion(), " classpath = " + System.getProperty("java.class.path"), " build = " + HiveVersionInfo.getUrl() + " -r " + HiveVersionInfo.getRevision() + "; compiled by '" + HiveVersionInfo.getUser() + "' on " + HiveVersionInfo.getDate() })); ShutdownHookManager.addShutdownHook(new Runnable() { @Override public void run() { LOG.info(toStartupShutdownString("SHUTDOWN_MSG: ", new String[] { "Shutting down " + classname + " at " + hostname })); } }, SHUTDOWN_HOOK_PRIORITY); } /** * Return hostname without throwing exception. * @return hostname */ public static String getHostname() { try { return "" + InetAddress.getLocalHost(); } catch (UnknownHostException uhe) { return "" + uhe; } } /** * The traditional binary prefixes, kilo, mega, ..., exa, * which can be represented by a 64-bit integer. * TraditionalBinaryPrefix symbol are case insensitive. */ public static enum TraditionalBinaryPrefix { KILO(1024), MEGA(KILO.value << 10), GIGA(MEGA.value << 10), TERA(GIGA.value << 10), PETA( TERA.value << 10), EXA(PETA.value << 10); public final long value; public final char symbol; TraditionalBinaryPrefix(long value) { this.value = value; this.symbol = toString().charAt(0); } /** * @return The TraditionalBinaryPrefix object corresponding to the symbol. */ public static TraditionalBinaryPrefix valueOf(char symbol) { symbol = Character.toUpperCase(symbol); for (TraditionalBinaryPrefix prefix : TraditionalBinaryPrefix.values()) { if (symbol == prefix.symbol) { return prefix; } } throw new IllegalArgumentException("Unknown symbol '" + symbol + "'"); } /** * Convert a string to long. * The input string is first be trimmed * and then it is parsed with traditional binary prefix. * * For example, * "-1230k" will be converted to -1230 * 1024 = -1259520; * "891g" will be converted to 891 * 1024^3 = 956703965184; * * @param s input string * @return a long value represented by the input string. */ public static long string2long(String s) { s = s.trim(); final int lastpos = s.length() - 1; final char lastchar = s.charAt(lastpos); if (Character.isDigit(lastchar)) { return Long.parseLong(s); } else { long prefix; try { prefix = TraditionalBinaryPrefix.valueOf(lastchar).value; } catch (IllegalArgumentException e) { throw new IllegalArgumentException("Invalid size prefix '" + lastchar + "' in '" + s + "'. Allowed prefixes are k, m, g, t, p, e(case insensitive)"); } long num = Long.parseLong(s.substring(0, lastpos)); if (num > (Long.MAX_VALUE / prefix) || num < (Long.MIN_VALUE / prefix)) { throw new IllegalArgumentException(s + " does not fit in a Long"); } return num * prefix; } } } /** * Escapes HTML Special characters present in the string. * @param string * @return HTML Escaped String representation */ public static String escapeHTML(String string) { if (string == null) { return null; } StringBuilder sb = new StringBuilder(); boolean lastCharacterWasSpace = false; char[] chars = string.toCharArray(); for (char c : chars) { if (c == ' ') { if (lastCharacterWasSpace) { lastCharacterWasSpace = false; sb.append(" "); } else { lastCharacterWasSpace = true; sb.append(" "); } } else { lastCharacterWasSpace = false; switch (c) { case '<': sb.append("<"); break; case '>': sb.append(">"); break; case '&': sb.append("&"); break; case '"': sb.append("""); break; default: sb.append(c); break; } } } return sb.toString(); } /** * Return an abbreviated English-language desc of the byte length */ public static String byteDesc(long len) { double val = 0.0; String ending = ""; if (len < 1024 * 1024) { val = (1.0 * len) / 1024; ending = " KB"; } else if (len < 1024 * 1024 * 1024) { val = (1.0 * len) / (1024 * 1024); ending = " MB"; } else if (len < 1024L * 1024 * 1024 * 1024) { val = (1.0 * len) / (1024 * 1024 * 1024); ending = " GB"; } else if (len < 1024L * 1024 * 1024 * 1024 * 1024) { val = (1.0 * len) / (1024L * 1024 * 1024 * 1024); ending = " TB"; } else { val = (1.0 * len) / (1024L * 1024 * 1024 * 1024 * 1024); ending = " PB"; } return limitDecimalTo2(val) + ending; } public static synchronized String limitDecimalTo2(double d) { return decimalFormat.format(d); } /** * Concatenates strings, using a separator. * * @param separator Separator to join with. * @param strings Strings to join. */ public static String join(CharSequence separator, Iterable<?> strings) { Iterator<?> i = strings.iterator(); if (!i.hasNext()) { return ""; } StringBuilder sb = new StringBuilder(i.next().toString()); while (i.hasNext()) { sb.append(separator); sb.append(i.next().toString()); } return sb.toString(); } /** * Concatenates strings, using a separator. Empty/blank string or null will be * ignored. * * @param strings Strings to join. * @param separator Separator to join with. */ public static String joinIgnoringEmpty(String[] strings, char separator) { ArrayList<String> list = new ArrayList<String>(); for (String str : strings) { if (StringUtils.isNotBlank(str)) { list.add(str); } } return StringUtils.join(list, separator); } /** * Convert SOME_STUFF to SomeStuff * * @param s input string * @return camelized string */ public static String camelize(String s) { StringBuilder sb = new StringBuilder(); String[] words = split(s.toLowerCase(Locale.US), ESCAPE_CHAR, '_'); for (String word : words) { sb.append(StringUtils.capitalize(word)); } return sb.toString(); } /** * Checks if b is the first byte of a UTF-8 character. * */ public static boolean isUtfStartByte(byte b) { return (b & 0xC0) != 0x80; } public static int getTextUtfLength(Text t) { byte[] data = t.getBytes(); int len = 0; for (int i = 0; i < t.getLength(); i++) { if (isUtfStartByte(data[i])) { len++; } } return len; } public static String normalizeIdentifier(String identifier) { return identifier.trim().toLowerCase(); } public static Map getPropertiesExplain(Properties properties) { if (properties != null) { String value = properties.getProperty("columns.comments"); if (value != null) { // should copy properties first Map clone = new HashMap(properties); clone.put("columns.comments", quoteComments(value)); return clone; } } return properties; } public static String quoteComments(String value) { char[] chars = value.toCharArray(); if (!commentProvided(chars)) { return null; } StringBuilder builder = new StringBuilder(); int prev = 0; for (int i = 0; i < chars.length; i++) { if (chars[i] == 0x00) { if (builder.length() > 0) { builder.append(','); } builder.append('\'').append(chars, prev, i - prev).append('\''); prev = i + 1; } } builder.append(",\'").append(chars, prev, chars.length - prev).append('\''); return builder.toString(); } public static boolean commentProvided(char[] chars) { for (char achar : chars) { if (achar != 0x00) { return true; } } return false; } public static String getPartitionValWithInvalidCharacter(List<String> partVals, Pattern partitionValidationPattern) { if (partitionValidationPattern == null) { return null; } for (String partVal : partVals) { if (!partitionValidationPattern.matcher(partVal).matches()) { return partVal; } } return null; } }