Languages.java

  1. /*
  2.  * Licensed to the Apache Software Foundation (ASF) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * The ASF licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *      http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */

  18. package org.apache.commons.codec.language.bm;

  20. import java.io.InputStream;
  21. import java.util.Collections;
  22. import java.util.EnumMap;
  23. import java.util.HashSet;
  24. import java.util.Map;
  25. import java.util.NoSuchElementException;
  26. import java.util.Scanner;
  27. import java.util.Set;

  29. /**
  30.  * Language codes.
  31.  * <p>
  32.  * Language codes are typically loaded from resource files. These are UTF-8 encoded text files. They are
  33.  * systematically named following the pattern:
  34.  * <blockquote>org/apache/commons/codec/language/bm/${{@link NameType#getName()} languages.txt</blockquote>
  35.  * <p>
  36.  * The format of these resources is the following:
  37.  * <ul>
  38.  * <li><b>Language:</b> a single string containing no whitespace</li>
  39.  * <li><b>End-of-line comments:</b> Any occurrence of '//' will cause all text following on that line to be
  40.  * discarded as a comment.</li>
  41.  * <li><b>Multi-line comments:</b> Any line starting with '/*' will start multi-line commenting mode.
  42.  * This will skip all content until a line ending in '*' and '/' is found.</li>
  43.  * <li><b>Blank lines:</b> All blank lines will be skipped.</li>
  44.  * </ul>
  45.  * <p>
  46.  * Ported from language.php
  47.  * <p>
  48.  * This class is immutable and thread-safe.
  49.  *
  50.  * @since 1.6
  51.  * @version $Id: Languages.java 1694610 2015-08-07 03:47:38Z ggregory $
  52.  */
  53. public class Languages {
  54.     // Implementation note: This class is divided into two sections. The first part is a static factory interface that
  55.     // exposes org/apache/commons/codec/language/bm/%s_languages.txt for %s in NameType.* as a list of supported
  56.     // languages, and a second part that provides instance methods for accessing this set for supported languages.

  58.     /**
  59.      * A set of languages.
  60.      */
  61.     public static abstract class LanguageSet {

  63.         public static LanguageSet from(final Set<String> langs) {
  64.             return langs.isEmpty() ? NO_LANGUAGES : new SomeLanguages(langs);
  65.         }

  67.         public abstract boolean contains(String language);

  69.         public abstract String getAny();

  71.         public abstract boolean isEmpty();

  73.         public abstract boolean isSingleton();

  75.         public abstract LanguageSet restrictTo(LanguageSet other);

  77.         abstract LanguageSet merge(LanguageSet other);
  78.     }

  80.     /**
  81.      * Some languages, explicitly enumerated.
  82.      */
  83.     public static final class SomeLanguages extends LanguageSet {
  84.         private final Set<String> languages;

  86.         private SomeLanguages(final Set<String> languages) {
  87.             this.languages = Collections.unmodifiableSet(languages);
  88.         }

  90.         @Override
  91.         public boolean contains(final String language) {
  92.             return this.languages.contains(language);
  93.         }

  95.         @Override
  96.         public String getAny() {
  97.             return this.languages.iterator().next();
  98.         }

  100.         public Set<String> getLanguages() {
  101.             return this.languages;
  102.         }

  104.         @Override
  105.         public boolean isEmpty() {
  106.             return this.languages.isEmpty();
  107.         }

  109.         @Override
  110.         public boolean isSingleton() {
  111.             return this.languages.size() == 1;
  112.         }

  114.         @Override
  115.         public LanguageSet restrictTo(final LanguageSet other) {
  116.             if (other == NO_LANGUAGES) {
  117.                 return other;
  118.             } else if (other == ANY_LANGUAGE) {
  119.                 return this;
  120.             } else {
  121.                 final SomeLanguages sl = (SomeLanguages) other;
  122.                 final Set<String> ls = new HashSet<String>(Math.min(languages.size(), sl.languages.size()));
  123.                 for (final String lang : languages) {
  124.                     if (sl.languages.contains(lang)) {
  125.                         ls.add(lang);
  126.                     }
  127.                 }
  128.                 return from(ls);
  129.             }
  130.         }

  132.         @Override
  133.         public LanguageSet merge(final LanguageSet other) {
  134.             if (other == NO_LANGUAGES) {
  135.                 return this;
  136.             } else if (other == ANY_LANGUAGE) {
  137.                 return other;
  138.             } else {
  139.                 final SomeLanguages sl = (SomeLanguages) other;
  140.                 final Set<String> ls = new HashSet<String>(languages);
  141.                 for (final String lang : sl.languages) {
  142.                   ls.add(lang);
  143.                 }
  144.                 return from(ls);
  145.             }
  146.         }

  148.         @Override
  149.         public String toString() {
  150.             return "Languages(" + languages.toString() + ")";
  151.         }

  153.     }

  155.     public static final String ANY = "any";

  157.     private static final Map<NameType, Languages> LANGUAGES = new EnumMap<NameType, Languages>(NameType.class);

  159.     static {
  160.         for (final NameType s : NameType.values()) {
  161.             LANGUAGES.put(s, getInstance(langResourceName(s)));
  162.         }
  163.     }

  165.     public static Languages getInstance(final NameType nameType) {
  166.         return LANGUAGES.get(nameType);
  167.     }

  169.     public static Languages getInstance(final String languagesResourceName) {
  170.         // read languages list
  171.         final Set<String> ls = new HashSet<String>();
  172.         final InputStream langIS = Languages.class.getClassLoader().getResourceAsStream(languagesResourceName);

  174.         if (langIS == null) {
  175.             throw new IllegalArgumentException("Unable to resolve required resource: " + languagesResourceName);
  176.         }

  178.         final Scanner lsScanner = new Scanner(langIS, ResourceConstants.ENCODING);
  179.         try {
  180.             boolean inExtendedComment = false;
  181.             while (lsScanner.hasNextLine()) {
  182.                 final String line = lsScanner.nextLine().trim();
  183.                 if (inExtendedComment) {
  184.                     if (line.endsWith(ResourceConstants.EXT_CMT_END)) {
  185.                         inExtendedComment = false;
  186.                     }
  187.                 } else {
  188.                     if (line.startsWith(ResourceConstants.EXT_CMT_START)) {
  189.                         inExtendedComment = true;
  190.                     } else if (line.length() > 0) {
  191.                         ls.add(line);
  192.                     }
  193.                 }
  194.             }
  195.         } finally {
  196.             lsScanner.close();
  197.         }

  199.         return new Languages(Collections.unmodifiableSet(ls));
  200.     }

  202.     private static String langResourceName(final NameType nameType) {
  203.         return String.format("org/apache/commons/codec/language/bm/%s_languages.txt", nameType.getName());
  204.     }

  206.     private final Set<String> languages;

  208.     /**
  209.      * No languages at all.
  210.      */
  211.     public static final LanguageSet NO_LANGUAGES = new LanguageSet() {
  212.         @Override
  213.         public boolean contains(final String language) {
  214.             return false;
  215.         }

  217.         @Override
  218.         public String getAny() {
  219.             throw new NoSuchElementException("Can't fetch any language from the empty language set.");
  220.         }

  222.         @Override
  223.         public boolean isEmpty() {
  224.             return true;
  225.         }

  227.         @Override
  228.         public boolean isSingleton() {
  229.             return false;
  230.         }

  232.         @Override
  233.         public LanguageSet restrictTo(final LanguageSet other) {
  234.             return this;
  235.         }

  237.         @Override
  238.         public LanguageSet merge(final LanguageSet other) {
  239.             return other;
  240.         }

  242.         @Override
  243.         public String toString() {
  244.             return "NO_LANGUAGES";
  245.         }
  246.     };

  248.     /**
  249.      * Any/all languages.
  250.      */
  251.     public static final LanguageSet ANY_LANGUAGE = new LanguageSet() {
  252.         @Override
  253.         public boolean contains(final String language) {
  254.             return true;
  255.         }

  257.         @Override
  258.         public String getAny() {
  259.             throw new NoSuchElementException("Can't fetch any language from the any language set.");
  260.         }

  262.         @Override
  263.         public boolean isEmpty() {
  264.             return false;
  265.         }

  267.         @Override
  268.         public boolean isSingleton() {
  269.             return false;
  270.         }

  272.         @Override
  273.         public LanguageSet restrictTo(final LanguageSet other) {
  274.             return other;
  275.         }

  277.         @Override
  278.         public LanguageSet merge(final LanguageSet other) {
  279.             return other;
  280.         }

  282.         @Override
  283.         public String toString() {
  284.             return "ANY_LANGUAGE";
  285.         }
  286.     };

  288.     private Languages(final Set<String> languages) {
  289.         this.languages = languages;
  290.     }

  292.     public Set<String> getLanguages() {
  293.         return this.languages;
  294.     }
  295. }
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