Java tutorial
/* * JBoss DNA (http://www.jboss.org/dna) * See the COPYRIGHT.txt file distributed with this work for information * regarding copyright ownership. Some portions may be licensed * to Red Hat, Inc. under one or more contributor license agreements. * See the AUTHORS.txt file in the distribution for a full listing of * individual contributors. * * JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA * is licensed to you under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * JBoss DNA is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ import java.util.HashSet; import java.util.LinkedList; import java.util.Set; import java.util.regex.Matcher; import java.util.regex.Pattern; /** * Transforms words to singular, plural, humanized (human readable), underscore, camel case, or ordinal form. This is inspired by * the <a href="http://api.rubyonrails.org/classes/Inflector.html">Inflector</a> class in <a * href="http://www.rubyonrails.org">Ruby on Rails</a>, which is distributed under the <a * href="http://wiki.rubyonrails.org/rails/pages/License">Rails license</a>. * * @author Randall Hauch */ public class Inflector { protected static final Inflector INSTANCE = new Inflector(); public static final Inflector getInstance() { return INSTANCE; } protected class Rule { protected final String expression; protected final Pattern expressionPattern; protected final String replacement; protected Rule(String expression, String replacement) { this.expression = expression; this.replacement = replacement != null ? replacement : ""; this.expressionPattern = Pattern.compile(this.expression, Pattern.CASE_INSENSITIVE); } /** * Apply the rule against the input string, returning the modified string or null if the rule didn't apply (and no * modifications were made) * * @param input the input string * @return the modified string if this rule applied, or null if the input was not modified by this rule */ protected String apply(String input) { Matcher matcher = this.expressionPattern.matcher(input); if (!matcher.find()) return null; return matcher.replaceAll(this.replacement); } @Override public int hashCode() { return expression.hashCode(); } @Override public boolean equals(Object obj) { if (obj == this) return true; if (obj != null && obj.getClass() == this.getClass()) { final Rule that = (Rule) obj; if (this.expression.equalsIgnoreCase(that.expression)) return true; } return false; } @Override public String toString() { return expression + ", " + replacement; } } private LinkedList<Rule> plurals = new LinkedList<Rule>(); private LinkedList<Rule> singulars = new LinkedList<Rule>(); /** * The lowercase words that are to be excluded and not processed. This map can be modified by the users via * {@link #getUncountables()}. */ private final Set<String> uncountables = new HashSet<String>(); public Inflector() { initialize(); } protected Inflector(Inflector original) { this.plurals.addAll(original.plurals); this.singulars.addAll(original.singulars); this.uncountables.addAll(original.uncountables); } @Override public Inflector clone() { return new Inflector(this); } // ------------------------------------------------------------------------------------------------ // Usage functions // ------------------------------------------------------------------------------------------------ /** * Returns the plural form of the word in the string. * <p> * Examples: * * <pre> * inflector.pluralize("post") #=> "posts" * inflector.pluralize("octopus") #=> "octopi" * inflector.pluralize("sheep") #=> "sheep" * inflector.pluralize("words") #=> "words" * inflector.pluralize("the blue mailman") #=> "the blue mailmen" * inflector.pluralize("CamelOctopus") #=> "CamelOctopi" * </pre> * * </p> * <p> * Note that if the {@link Object#toString()} is called on the supplied object, so this method works for non-strings, too. * </p> * * @param word the word that is to be pluralized. * @return the pluralized form of the word, or the word itself if it could not be pluralized * @see #singularize(Object) */ public String pluralize(Object word) { if (word == null) return null; String wordStr = word.toString().trim(); if (wordStr.length() == 0) return wordStr; if (isUncountable(wordStr)) return wordStr; for (Rule rule : this.plurals) { String result = rule.apply(wordStr); if (result != null) return result; } return wordStr; } public String pluralize(Object word, int count) { if (word == null) return null; if (count == 1 || count == -1) { return word.toString(); } return pluralize(word); } /** * Returns the singular form of the word in the string. * <p> * Examples: * * <pre> * inflector.singularize("posts") #=> "post" * inflector.singularize("octopi") #=> "octopus" * inflector.singularize("sheep") #=> "sheep" * inflector.singularize("words") #=> "word" * inflector.singularize("the blue mailmen") #=> "the blue mailman" * inflector.singularize("CamelOctopi") #=> "CamelOctopus" * </pre> * * </p> * <p> * Note that if the {@link Object#toString()} is called on the supplied object, so this method works for non-strings, too. * </p> * * @param word the word that is to be pluralized. * @return the pluralized form of the word, or the word itself if it could not be pluralized * @see #pluralize(Object) */ public String singularize(Object word) { if (word == null) return null; String wordStr = word.toString().trim(); if (wordStr.length() == 0) return wordStr; if (isUncountable(wordStr)) return wordStr; for (Rule rule : this.singulars) { String result = rule.apply(wordStr); if (result != null) return result; } return wordStr; } /** * Converts strings to lowerCamelCase. This method will also use any extra delimiter characters to identify word boundaries. * <p> * Examples: * * <pre> * inflector.lowerCamelCase("active_record") #=> "activeRecord" * inflector.lowerCamelCase("first_name") #=> "firstName" * inflector.lowerCamelCase("name") #=> "name" * inflector.lowerCamelCase("the-first_name",'-') #=> "theFirstName" * </pre> * * </p> * * @param lowerCaseAndUnderscoredWord the word that is to be converted to camel case * @param delimiterChars optional characters that are used to delimit word boundaries * @return the lower camel case version of the word * @see #underscore(String, char[]) * @see #camelCase(String, boolean, char[]) * @see #upperCamelCase(String, char[]) */ public String lowerCamelCase(String lowerCaseAndUnderscoredWord, char... delimiterChars) { return camelCase(lowerCaseAndUnderscoredWord, false, delimiterChars); } /** * Converts strings to UpperCamelCase. This method will also use any extra delimiter characters to identify word boundaries. * <p> * Examples: * * <pre> * inflector.upperCamelCase("active_record") #=> "SctiveRecord" * inflector.upperCamelCase("first_name") #=> "FirstName" * inflector.upperCamelCase("name") #=> "Name" * inflector.lowerCamelCase("the-first_name",'-') #=> "TheFirstName" * </pre> * * </p> * * @param lowerCaseAndUnderscoredWord the word that is to be converted to camel case * @param delimiterChars optional characters that are used to delimit word boundaries * @return the upper camel case version of the word * @see #underscore(String, char[]) * @see #camelCase(String, boolean, char[]) * @see #lowerCamelCase(String, char[]) */ public String upperCamelCase(String lowerCaseAndUnderscoredWord, char... delimiterChars) { return camelCase(lowerCaseAndUnderscoredWord, true, delimiterChars); } /** * By default, this method converts strings to UpperCamelCase. If the <code>uppercaseFirstLetter</code> argument to false, * then this method produces lowerCamelCase. This method will also use any extra delimiter characters to identify word * boundaries. * <p> * Examples: * * <pre> * inflector.camelCase("active_record",false) #=> "activeRecord" * inflector.camelCase("active_record",true) #=> "ActiveRecord" * inflector.camelCase("first_name",false) #=> "firstName" * inflector.camelCase("first_name",true) #=> "FirstName" * inflector.camelCase("name",false) #=> "name" * inflector.camelCase("name",true) #=> "Name" * </pre> * * </p> * * @param lowerCaseAndUnderscoredWord the word that is to be converted to camel case * @param uppercaseFirstLetter true if the first character is to be uppercased, or false if the first character is to be * lowercased * @param delimiterChars optional characters that are used to delimit word boundaries * @return the camel case version of the word * @see #underscore(String, char[]) * @see #upperCamelCase(String, char[]) * @see #lowerCamelCase(String, char[]) */ public String camelCase(String lowerCaseAndUnderscoredWord, boolean uppercaseFirstLetter, char... delimiterChars) { if (lowerCaseAndUnderscoredWord == null) return null; lowerCaseAndUnderscoredWord = lowerCaseAndUnderscoredWord.trim(); if (lowerCaseAndUnderscoredWord.length() == 0) return ""; if (uppercaseFirstLetter) { String result = lowerCaseAndUnderscoredWord; // Replace any extra delimiters with underscores (before the underscores are converted in the next step)... if (delimiterChars != null) { for (char delimiterChar : delimiterChars) { result = result.replace(delimiterChar, '_'); } } // Change the case at the beginning at after each underscore ... return replaceAllWithUppercase(result, "(^|_)(.)", 2); } if (lowerCaseAndUnderscoredWord.length() < 2) return lowerCaseAndUnderscoredWord; return "" + Character.toLowerCase(lowerCaseAndUnderscoredWord.charAt(0)) + camelCase(lowerCaseAndUnderscoredWord, true, delimiterChars).substring(1); } /** * Makes an underscored form from the expression in the string (the reverse of the {@link #camelCase(String, boolean, char[]) * camelCase} method. Also changes any characters that match the supplied delimiters into underscore. * <p> * Examples: * * <pre> * inflector.underscore("activeRecord") #=> "active_record" * inflector.underscore("ActiveRecord") #=> "active_record" * inflector.underscore("firstName") #=> "first_name" * inflector.underscore("FirstName") #=> "first_name" * inflector.underscore("name") #=> "name" * inflector.underscore("The.firstName") #=> "the_first_name" * </pre> * * </p> * * @param camelCaseWord the camel-cased word that is to be converted; * @param delimiterChars optional characters that are used to delimit word boundaries (beyond capitalization) * @return a lower-cased version of the input, with separate words delimited by the underscore character. */ public String underscore(String camelCaseWord, char... delimiterChars) { if (camelCaseWord == null) return null; String result = camelCaseWord.trim(); if (result.length() == 0) return ""; result = result.replaceAll("([A-Z]+)([A-Z][a-z])", "$1_$2"); result = result.replaceAll("([a-z\\d])([A-Z])", "$1_$2"); result = result.replace('-', '_'); if (delimiterChars != null) { for (char delimiterChar : delimiterChars) { result = result.replace(delimiterChar, '_'); } } return result.toLowerCase(); } /** * Returns a copy of the input with the first character converted to uppercase and the remainder to lowercase. * * @param words the word to be capitalized * @return the string with the first character capitalized and the remaining characters lowercased */ public String capitalize(String words) { if (words == null) return null; String result = words.trim(); if (result.length() == 0) return ""; if (result.length() == 1) return result.toUpperCase(); return "" + Character.toUpperCase(result.charAt(0)) + result.substring(1).toLowerCase(); } /** * Capitalizes the first word and turns underscores into spaces and strips trailing "_id" and any supplied removable tokens. * Like {@link #titleCase(String, String[])}, this is meant for creating pretty output. * <p> * Examples: * * <pre> * inflector.humanize("employee_salary") #=> "Employee salary" * inflector.humanize("author_id") #=> "Author" * </pre> * * </p> * * @param lowerCaseAndUnderscoredWords the input to be humanized * @param removableTokens optional array of tokens that are to be removed * @return the humanized string * @see #titleCase(String, String[]) */ public String humanize(String lowerCaseAndUnderscoredWords, String... removableTokens) { if (lowerCaseAndUnderscoredWords == null) return null; String result = lowerCaseAndUnderscoredWords.trim(); if (result.length() == 0) return ""; // Remove a trailing "_id" token result = result.replaceAll("_id$", ""); // Remove all of the tokens that should be removed if (removableTokens != null) { for (String removableToken : removableTokens) { result = result.replaceAll(removableToken, ""); } } result = result.replaceAll("_+", " "); // replace all adjacent underscores with a single space return capitalize(result); } /** * Capitalizes all the words and replaces some characters in the string to create a nicer looking title. Underscores are * changed to spaces, a trailing "_id" is removed, and any of the supplied tokens are removed. Like * {@link #humanize(String, String[])}, this is meant for creating pretty output. * <p> * Examples: * * <pre> * inflector.titleCase("man from the boondocks") #=> "Man From The Boondocks" * inflector.titleCase("x-men: the last stand") #=> "X Men: The Last Stand" * </pre> * * </p> * * @param words the input to be turned into title case * @param removableTokens optional array of tokens that are to be removed * @return the title-case version of the supplied words */ public String titleCase(String words, String... removableTokens) { String result = humanize(words, removableTokens); result = replaceAllWithUppercase(result, "\\b([a-z])", 1); // change first char of each word to uppercase return result; } /** * Turns a non-negative number into an ordinal string used to denote the position in an ordered sequence, such as 1st, 2nd, * 3rd, 4th. * * @param number the non-negative number * @return the string with the number and ordinal suffix */ public String ordinalize(int number) { int remainder = number % 100; String numberStr = Integer.toString(number); if (11 <= number && number <= 13) return numberStr + "th"; remainder = number % 10; if (remainder == 1) return numberStr + "st"; if (remainder == 2) return numberStr + "nd"; if (remainder == 3) return numberStr + "rd"; return numberStr + "th"; } // ------------------------------------------------------------------------------------------------ // Management methods // ------------------------------------------------------------------------------------------------ /** * Determine whether the supplied word is considered uncountable by the {@link #pluralize(Object) pluralize} and * {@link #singularize(Object) singularize} methods. * * @param word the word * @return true if the plural and singular forms of the word are the same */ public boolean isUncountable(String word) { if (word == null) return false; String trimmedLower = word.trim().toLowerCase(); return this.uncountables.contains(trimmedLower); } /** * Get the set of words that are not processed by the Inflector. The resulting map is directly modifiable. * * @return the set of uncountable words */ public Set<String> getUncountables() { return uncountables; } public void addPluralize(String rule, String replacement) { final Rule pluralizeRule = new Rule(rule, replacement); this.plurals.addFirst(pluralizeRule); } public void addSingularize(String rule, String replacement) { final Rule singularizeRule = new Rule(rule, replacement); this.singulars.addFirst(singularizeRule); } public void addIrregular(String singular, String plural) { //CheckArg.isNotEmpty(singular, "singular rule"); //CheckArg.isNotEmpty(plural, "plural rule"); String singularRemainder = singular.length() > 1 ? singular.substring(1) : ""; String pluralRemainder = plural.length() > 1 ? plural.substring(1) : ""; addPluralize("(" + singular.charAt(0) + ")" + singularRemainder + "$", "$1" + pluralRemainder); addSingularize("(" + plural.charAt(0) + ")" + pluralRemainder + "$", "$1" + singularRemainder); } public void addUncountable(String... words) { if (words == null || words.length == 0) return; for (String word : words) { if (word != null) uncountables.add(word.trim().toLowerCase()); } } /** * Utility method to replace all occurrences given by the specific backreference with its uppercased form, and remove all * other backreferences. * <p> * The Java {@link Pattern regular expression processing} does not use the preprocessing directives <code>\l</code>, * <code>\u</code>, <code>\L</code>, and <code>\U</code>. If so, such directives could be used in the replacement string * to uppercase or lowercase the backreferences. For example, <code>\L1</code> would lowercase the first backreference, and * <code>\u3</code> would uppercase the 3rd backreference. * </p> * * @param input * @param regex * @param groupNumberToUppercase * @return the input string with the appropriate characters converted to upper-case */ protected static String replaceAllWithUppercase(String input, String regex, int groupNumberToUppercase) { Pattern underscoreAndDotPattern = Pattern.compile(regex); Matcher matcher = underscoreAndDotPattern.matcher(input); StringBuffer sb = new StringBuffer(); while (matcher.find()) { matcher.appendReplacement(sb, matcher.group(groupNumberToUppercase).toUpperCase()); } matcher.appendTail(sb); return sb.toString(); } /** * Completely remove all rules within this inflector. */ public void clear() { this.uncountables.clear(); this.plurals.clear(); this.singulars.clear(); } protected void initialize() { Inflector inflect = this; inflect.addPluralize("$", "s"); inflect.addPluralize("s$", "s"); inflect.addPluralize("(ax|test)is$", "$1es"); inflect.addPluralize("(octop|vir)us$", "$1i"); inflect.addPluralize("(octop|vir)i$", "$1i"); // already plural inflect.addPluralize("(alias|status)$", "$1es"); inflect.addPluralize("(bu)s$", "$1ses"); inflect.addPluralize("(buffal|tomat)o$", "$1oes"); inflect.addPluralize("([ti])um$", "$1a"); inflect.addPluralize("([ti])a$", "$1a"); // already plural inflect.addPluralize("sis$", "ses"); inflect.addPluralize("(?:([^f])fe|([lr])f)$", "$1$2ves"); inflect.addPluralize("(hive)$", "$1s"); inflect.addPluralize("([^aeiouy]|qu)y$", "$1ies"); inflect.addPluralize("(x|ch|ss|sh)$", "$1es"); inflect.addPluralize("(matr|vert|ind)ix|ex$", "$1ices"); inflect.addPluralize("([m|l])ouse$", "$1ice"); inflect.addPluralize("([m|l])ice$", "$1ice"); inflect.addPluralize("^(ox)$", "$1en"); inflect.addPluralize("(quiz)$", "$1zes"); // Need to check for the following words that are already pluralized: inflect.addPluralize("(people|men|children|sexes|moves|stadiums)$", "$1"); // irregulars inflect.addPluralize("(oxen|octopi|viri|aliases|quizzes)$", "$1"); // special rules inflect.addSingularize("s$", ""); inflect.addSingularize("(s|si|u)s$", "$1s"); // '-us' and '-ss' are already singular inflect.addSingularize("(n)ews$", "$1ews"); inflect.addSingularize("([ti])a$", "$1um"); inflect.addSingularize("((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)ses$", "$1$2sis"); inflect.addSingularize("(^analy)ses$", "$1sis"); inflect.addSingularize("(^analy)sis$", "$1sis"); // already singular, but ends in 's' inflect.addSingularize("([^f])ves$", "$1fe"); inflect.addSingularize("(hive)s$", "$1"); inflect.addSingularize("(tive)s$", "$1"); inflect.addSingularize("([lr])ves$", "$1f"); inflect.addSingularize("([^aeiouy]|qu)ies$", "$1y"); inflect.addSingularize("(s)eries$", "$1eries"); inflect.addSingularize("(m)ovies$", "$1ovie"); inflect.addSingularize("(x|ch|ss|sh)es$", "$1"); inflect.addSingularize("([m|l])ice$", "$1ouse"); inflect.addSingularize("(bus)es$", "$1"); inflect.addSingularize("(o)es$", "$1"); inflect.addSingularize("(shoe)s$", "$1"); inflect.addSingularize("(cris|ax|test)is$", "$1is"); // already singular, but ends in 's' inflect.addSingularize("(cris|ax|test)es$", "$1is"); inflect.addSingularize("(octop|vir)i$", "$1us"); inflect.addSingularize("(octop|vir)us$", "$1us"); // already singular, but ends in 's' inflect.addSingularize("(alias|status)es$", "$1"); inflect.addSingularize("(alias|status)$", "$1"); // already singular, but ends in 's' inflect.addSingularize("^(ox)en", "$1"); inflect.addSingularize("(vert|ind)ices$", "$1ex"); inflect.addSingularize("(matr)ices$", "$1ix"); inflect.addSingularize("(quiz)zes$", "$1"); inflect.addIrregular("person", "people"); inflect.addIrregular("man", "men"); inflect.addIrregular("child", "children"); inflect.addIrregular("sex", "sexes"); inflect.addIrregular("move", "moves"); inflect.addIrregular("stadium", "stadiums"); inflect.addUncountable("equipment", "information", "rice", "money", "species", "series", "fish", "sheep"); } }