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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   */
17  package org.apache.commons.lang3;
18  
19  import java.lang.reflect.Method;
20  import java.lang.reflect.Modifier;
21  import java.util.ArrayList;
22  import java.util.Arrays;
23  import java.util.Collections;
24  import java.util.Comparator;
25  import java.util.HashMap;
26  import java.util.HashSet;
27  import java.util.Iterator;
28  import java.util.LinkedHashSet;
29  import java.util.List;
30  import java.util.Map;
31  import java.util.Objects;
32  import java.util.Set;
33  import java.util.stream.Collectors;
34  
35  import org.apache.commons.lang3.mutable.MutableObject;
36  
37  /**
38   * Operates on classes without using reflection.
39   *
40   * <p>
41   * This class handles invalid {@code null} inputs as best it can. Each method documents its behavior in more detail.
42   * </p>
43   *
44   * <p>
45   * The notion of a {@code canonical name} includes the human readable name for the type, for example {@code int[]}. The
46   * non-canonical method variants work with the JVM names, such as {@code [I}.
47   * </p>
48   *
49   * @since 2.0
50   */
51  public class ClassUtils {
52  
53      /**
54       * Inclusivity literals for {@link #hierarchy(Class, Interfaces)}.
55       *
56       * @since 3.2
57       */
58      public enum Interfaces {
59  
60          /** Includes interfaces. */
61          INCLUDE,
62  
63          /** Excludes interfaces. */
64          EXCLUDE
65      }
66  
67      private static final Comparator<Class<?>> COMPARATOR = (o1, o2) -> Objects.compare(getName(o1), getName(o2), String::compareTo);
68  
69      /**
70       * The package separator character: {@code '&#x2e;' == {@value}}.
71       */
72      public static final char PACKAGE_SEPARATOR_CHAR = '.';
73  
74      /**
75       * The package separator String: {@code "&#x2e;"}.
76       */
77      public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);
78  
79      /**
80       * The inner class separator character: {@code '$' == {@value}}.
81       */
82      public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
83  
84      /**
85       * The inner class separator String: {@code "$"}.
86       */
87      public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
88  
89      /**
90       * Maps names of primitives to their corresponding primitive {@link Class}es.
91       */
92      private static final Map<String, Class<?>> namePrimitiveMap = new HashMap<>();
93  
94      static {
95          namePrimitiveMap.put("boolean", Boolean.TYPE);
96          namePrimitiveMap.put("byte", Byte.TYPE);
97          namePrimitiveMap.put("char", Character.TYPE);
98          namePrimitiveMap.put("short", Short.TYPE);
99          namePrimitiveMap.put("int", Integer.TYPE);
100         namePrimitiveMap.put("long", Long.TYPE);
101         namePrimitiveMap.put("double", Double.TYPE);
102         namePrimitiveMap.put("float", Float.TYPE);
103         namePrimitiveMap.put("void", Void.TYPE);
104     }
105 
106     /**
107      * Maps primitive {@link Class}es to their corresponding wrapper {@link Class}.
108      */
109     private static final Map<Class<?>, Class<?>> primitiveWrapperMap = new HashMap<>();
110 
111     static {
112         primitiveWrapperMap.put(Boolean.TYPE, Boolean.class);
113         primitiveWrapperMap.put(Byte.TYPE, Byte.class);
114         primitiveWrapperMap.put(Character.TYPE, Character.class);
115         primitiveWrapperMap.put(Short.TYPE, Short.class);
116         primitiveWrapperMap.put(Integer.TYPE, Integer.class);
117         primitiveWrapperMap.put(Long.TYPE, Long.class);
118         primitiveWrapperMap.put(Double.TYPE, Double.class);
119         primitiveWrapperMap.put(Float.TYPE, Float.class);
120         primitiveWrapperMap.put(Void.TYPE, Void.TYPE);
121     }
122 
123     /**
124      * Maps wrapper {@link Class}es to their corresponding primitive types.
125      */
126     private static final Map<Class<?>, Class<?>> wrapperPrimitiveMap = new HashMap<>();
127 
128     static {
129         primitiveWrapperMap.forEach((primitiveClass, wrapperClass) -> {
130             if (!primitiveClass.equals(wrapperClass)) {
131                 wrapperPrimitiveMap.put(wrapperClass, primitiveClass);
132             }
133         });
134     }
135 
136     /**
137      * Maps a primitive class name to its corresponding abbreviation used in array class names.
138      */
139     private static final Map<String, String> abbreviationMap;
140 
141     /**
142      * Maps an abbreviation used in array class names to corresponding primitive class name.
143      */
144     private static final Map<String, String> reverseAbbreviationMap;
145 
146     /** Feed abbreviation maps. */
147     static {
148         final Map<String, String> map = new HashMap<>();
149         map.put("int", "I");
150         map.put("boolean", "Z");
151         map.put("float", "F");
152         map.put("long", "J");
153         map.put("short", "S");
154         map.put("byte", "B");
155         map.put("double", "D");
156         map.put("char", "C");
157         abbreviationMap = Collections.unmodifiableMap(map);
158         reverseAbbreviationMap = Collections.unmodifiableMap(map.entrySet().stream().collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey)));
159     }
160 
161     /**
162      * Gets the class comparator, comparing by class name.
163      *
164      * @return the class comparator.
165      * @since 3.13.0
166      */
167     public static Comparator<Class<?>> comparator() {
168         return COMPARATOR;
169     }
170 
171     /**
172      * Given a {@link List} of {@link Class} objects, this method converts them into class names.
173      *
174      * <p>
175      * A new {@link List} is returned. {@code null} objects will be copied into the returned list as {@code null}.
176      * </p>
177      *
178      * @param classes the classes to change
179      * @return a {@link List} of class names corresponding to the Class objects, {@code null} if null input
180      * @throws ClassCastException if {@code classes} contains a non-{@link Class} entry
181      */
182     public static List<String> convertClassesToClassNames(final List<Class<?>> classes) {
183         return classes == null ? null : classes.stream().map(e -> getName(e, null)).collect(Collectors.toList());
184     }
185 
186     /**
187      * Given a {@link List} of class names, this method converts them into classes.
188      *
189      * <p>
190      * A new {@link List} is returned. If the class name cannot be found, {@code null} is stored in the {@link List}. If the
191      * class name in the {@link List} is {@code null}, {@code null} is stored in the output {@link List}.
192      * </p>
193      *
194      * @param classNames the classNames to change
195      * @return a {@link List} of Class objects corresponding to the class names, {@code null} if null input
196      * @throws ClassCastException if classNames contains a non String entry
197      */
198     public static List<Class<?>> convertClassNamesToClasses(final List<String> classNames) {
199         if (classNames == null) {
200             return null;
201         }
202         final List<Class<?>> classes = new ArrayList<>(classNames.size());
203         classNames.forEach(className -> {
204             try {
205                 classes.add(Class.forName(className));
206             } catch (final Exception ex) {
207                 classes.add(null);
208             }
209         });
210         return classes;
211     }
212 
213     /**
214      * Gets the abbreviated name of a {@link Class}.
215      *
216      * @param cls the class to get the abbreviated name for, may be {@code null}
217      * @param lengthHint the desired length of the abbreviated name
218      * @return the abbreviated name or an empty string
219      * @throws IllegalArgumentException if len &lt;= 0
220      * @see #getAbbreviatedName(String, int)
221      * @since 3.4
222      */
223     public static String getAbbreviatedName(final Class<?> cls, final int lengthHint) {
224         if (cls == null) {
225             return StringUtils.EMPTY;
226         }
227         return getAbbreviatedName(cls.getName(), lengthHint);
228     }
229 
230     /**
231      * Gets the abbreviated class name from a {@link String}.
232      *
233      * <p>
234      * The string passed in is assumed to be a class name - it is not checked.
235      * </p>
236      *
237      * <p>
238      * The abbreviation algorithm will shorten the class name, usually without significant loss of meaning.
239      * </p>
240      *
241      * <p>
242      * The abbreviated class name will always include the complete package hierarchy. If enough space is available,
243      * rightmost sub-packages will be displayed in full length. The abbreviated package names will be shortened to a single
244      * character.
245      * </p>
246      * <p>
247      * Only package names are shortened, the class simple name remains untouched. (See examples.)
248      * </p>
249      * <p>
250      * The result will be longer than the desired length only if all the package names shortened to a single character plus
251      * the class simple name with the separating dots together are longer than the desired length. In other words, when the
252      * class name cannot be shortened to the desired length.
253      * </p>
254      * <p>
255      * If the class name can be shortened then the final length will be at most {@code lengthHint} characters.
256      * </p>
257      * <p>
258      * If the {@code lengthHint} is zero or negative then the method throws exception. If you want to achieve the shortest
259      * possible version then use {@code 1} as a {@code lengthHint}.
260      * </p>
261      *
262      * <table>
263      * <caption>Examples</caption>
264      * <tr>
265      * <td>className</td>
266      * <td>len</td>
267      * <td>return</td>
268      * </tr>
269      * <tr>
270      * <td>null</td>
271      * <td>1</td>
272      * <td>""</td>
273      * </tr>
274      * <tr>
275      * <td>"java.lang.String"</td>
276      * <td>5</td>
277      * <td>"j.l.String"</td>
278      * </tr>
279      * <tr>
280      * <td>"java.lang.String"</td>
281      * <td>15</td>
282      * <td>"j.lang.String"</td>
283      * </tr>
284      * <tr>
285      * <td>"java.lang.String"</td>
286      * <td>30</td>
287      * <td>"java.lang.String"</td>
288      * </tr>
289      * <tr>
290      * <td>"org.apache.commons.lang3.ClassUtils"</td>
291      * <td>18</td>
292      * <td>"o.a.c.l.ClassUtils"</td>
293      * </tr>
294      * </table>
295      *
296      * @param className the className to get the abbreviated name for, may be {@code null}
297      * @param lengthHint the desired length of the abbreviated name
298      * @return the abbreviated name or an empty string if the specified class name is {@code null} or empty string. The
299      *         abbreviated name may be longer than the desired length if it cannot be abbreviated to the desired length.
300      * @throws IllegalArgumentException if {@code len <= 0}
301      * @since 3.4
302      */
303     public static String getAbbreviatedName(final String className, final int lengthHint) {
304         if (lengthHint <= 0) {
305             throw new IllegalArgumentException("len must be > 0");
306         }
307         if (className == null) {
308             return StringUtils.EMPTY;
309         }
310         if (className.length() <= lengthHint) {
311             return className;
312         }
313         final char[] abbreviated = className.toCharArray();
314         int target = 0;
315         int source = 0;
316         while (source < abbreviated.length) {
317             // copy the next part
318             int runAheadTarget = target;
319             while (source < abbreviated.length && abbreviated[source] != '.') {
320                 abbreviated[runAheadTarget++] = abbreviated[source++];
321             }
322 
323             ++target;
324             if (useFull(runAheadTarget, source, abbreviated.length, lengthHint) || target > runAheadTarget) {
325                 target = runAheadTarget;
326             }
327 
328             // copy the '.' unless it was the last part
329             if (source < abbreviated.length) {
330                 abbreviated[target++] = abbreviated[source++];
331             }
332         }
333         return new String(abbreviated, 0, target);
334     }
335 
336     /**
337      * Gets a {@link List} of all interfaces implemented by the given class and its superclasses.
338      *
339      * <p>
340      * The order is determined by looking through each interface in turn as declared in the source file and following its
341      * hierarchy up. Then each superclass is considered in the same way. Later duplicates are ignored, so the order is
342      * maintained.
343      * </p>
344      *
345      * @param cls the class to look up, may be {@code null}
346      * @return the {@link List} of interfaces in order, {@code null} if null input
347      */
348     public static List<Class<?>> getAllInterfaces(final Class<?> cls) {
349         if (cls == null) {
350             return null;
351         }
352 
353         final LinkedHashSet<Class<?>> interfacesFound = new LinkedHashSet<>();
354         getAllInterfaces(cls, interfacesFound);
355 
356         return new ArrayList<>(interfacesFound);
357     }
358 
359     /**
360      * Gets the interfaces for the specified class.
361      *
362      * @param cls the class to look up, may be {@code null}
363      * @param interfacesFound the {@link Set} of interfaces for the class
364      */
365     private static void getAllInterfaces(Class<?> cls, final HashSet<Class<?>> interfacesFound) {
366         while (cls != null) {
367             final Class<?>[] interfaces = cls.getInterfaces();
368 
369             for (final Class<?> i : interfaces) {
370                 if (interfacesFound.add(i)) {
371                     getAllInterfaces(i, interfacesFound);
372                 }
373             }
374 
375             cls = cls.getSuperclass();
376         }
377     }
378 
379     /**
380      * Gets a {@link List} of superclasses for the given class.
381      *
382      * @param cls the class to look up, may be {@code null}
383      * @return the {@link List} of superclasses in order going up from this one {@code null} if null input
384      */
385     public static List<Class<?>> getAllSuperclasses(final Class<?> cls) {
386         if (cls == null) {
387             return null;
388         }
389         final List<Class<?>> classes = new ArrayList<>();
390         Class<?> superclass = cls.getSuperclass();
391         while (superclass != null) {
392             classes.add(superclass);
393             superclass = superclass.getSuperclass();
394         }
395         return classes;
396     }
397 
398     /**
399      * Gets the canonical class name for a {@link Class}.
400      *
401      * @param cls the class for which to get the canonical class name; may be null
402      * @return the canonical name of the class, or the empty String
403      * @since 3.7
404      * @see Class#getCanonicalName()
405      */
406     public static String getCanonicalName(final Class<?> cls) {
407         return getCanonicalName(cls, StringUtils.EMPTY);
408     }
409 
410     /**
411      * Gets the canonical name for a {@link Class}.
412      *
413      * @param cls the class for which to get the canonical class name; may be null
414      * @param valueIfNull the return value if null
415      * @return the canonical name of the class, or {@code valueIfNull}
416      * @since 3.7
417      * @see Class#getCanonicalName()
418      */
419     public static String getCanonicalName(final Class<?> cls, final String valueIfNull) {
420         if (cls == null) {
421             return valueIfNull;
422         }
423         final String canonicalName = cls.getCanonicalName();
424         return canonicalName == null ? valueIfNull : canonicalName;
425     }
426 
427     /**
428      * Gets the canonical name for an {@link Object}.
429      *
430      * @param object the object for which to get the canonical class name; may be null
431      * @return the canonical name of the object, or the empty String
432      * @since 3.7
433      * @see Class#getCanonicalName()
434      */
435     public static String getCanonicalName(final Object object) {
436         return getCanonicalName(object, StringUtils.EMPTY);
437     }
438 
439     /**
440      * Gets the canonical name for an {@link Object}.
441      *
442      * @param object the object for which to get the canonical class name; may be null
443      * @param valueIfNull the return value if null
444      * @return the canonical name of the object or {@code valueIfNull}
445      * @since 3.7
446      * @see Class#getCanonicalName()
447      */
448     public static String getCanonicalName(final Object object, final String valueIfNull) {
449         if (object == null) {
450             return valueIfNull;
451         }
452         final String canonicalName = object.getClass().getCanonicalName();
453         return canonicalName == null ? valueIfNull : canonicalName;
454     }
455 
456     /**
457      * Converts a given name of class into canonical format. If name of class is not a name of array class it returns
458      * unchanged name.
459      *
460      * <p>
461      * The method does not change the {@code $} separators in case the class is inner class.
462      * </p>
463      *
464      * <p>
465      * Example:
466      * <ul>
467      * <li>{@code getCanonicalName("[I") = "int[]"}</li>
468      * <li>{@code getCanonicalName("[Ljava.lang.String;") = "java.lang.String[]"}</li>
469      * <li>{@code getCanonicalName("java.lang.String") = "java.lang.String"}</li>
470      * </ul>
471      * </p>
472      *
473      * @param className the name of class
474      * @return canonical form of class name
475      * @since 2.4
476      */
477     private static String getCanonicalName(String className) {
478         className = StringUtils.deleteWhitespace(className);
479         if (className == null) {
480             return null;
481         }
482         int dim = 0;
483         while (className.startsWith("[")) {
484             dim++;
485             className = className.substring(1);
486         }
487         if (dim < 1) {
488             return className;
489         }
490         if (className.startsWith("L")) {
491             className = className.substring(1, className.endsWith(";") ? className.length() - 1 : className.length());
492         } else if (!className.isEmpty()) {
493             className = reverseAbbreviationMap.get(className.substring(0, 1));
494         }
495         final StringBuilder canonicalClassNameBuffer = new StringBuilder(className);
496         for (int i = 0; i < dim; i++) {
497             canonicalClassNameBuffer.append("[]");
498         }
499         return canonicalClassNameBuffer.toString();
500     }
501 
502     /**
503      * Returns the (initialized) class represented by {@code className} using the {@code classLoader}. This implementation
504      * supports the syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
505      * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
506      *
507      * @param classLoader the class loader to use to load the class
508      * @param className the class name
509      * @return the class represented by {@code className} using the {@code classLoader}
510      * @throws NullPointerException if the className is null
511      * @throws ClassNotFoundException if the class is not found
512      */
513     public static Class<?> getClass(final ClassLoader classLoader, final String className) throws ClassNotFoundException {
514         return getClass(classLoader, className, true);
515     }
516 
517     /**
518      * Returns the class represented by {@code className} using the {@code classLoader}. This implementation supports the
519      * syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}", and
520      * "{@code [Ljava.util.Map$Entry;}".
521      *
522      * @param classLoader the class loader to use to load the class
523      * @param className the class name
524      * @param initialize whether the class must be initialized
525      * @return the class represented by {@code className} using the {@code classLoader}
526      * @throws NullPointerException if the className is null
527      * @throws ClassNotFoundException if the class is not found
528      */
529     public static Class<?> getClass(final ClassLoader classLoader, final String className, final boolean initialize) throws ClassNotFoundException {
530         try {
531             Class<?> clazz = namePrimitiveMap.get(className);
532             return clazz != null ? clazz : Class.forName(toCanonicalName(className), initialize, classLoader);
533         } catch (final ClassNotFoundException ex) {
534             // allow path separators (.) as inner class name separators
535             final int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
536 
537             if (lastDotIndex != -1) {
538                 try {
539                     return getClass(classLoader, className.substring(0, lastDotIndex) + INNER_CLASS_SEPARATOR_CHAR + className.substring(lastDotIndex + 1),
540                         initialize);
541                 } catch (final ClassNotFoundException ignored) {
542                     // ignore exception
543                 }
544             }
545 
546             throw ex;
547         }
548     }
549 
550     /**
551      * Returns the (initialized) class represented by {@code className} using the current thread's context class loader.
552      * This implementation supports the syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
553      * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
554      *
555      * @param className the class name
556      * @return the class represented by {@code className} using the current thread's context class loader
557      * @throws NullPointerException if the className is null
558      * @throws ClassNotFoundException if the class is not found
559      */
560     public static Class<?> getClass(final String className) throws ClassNotFoundException {
561         return getClass(className, true);
562     }
563 
564     /**
565      * Returns the class represented by {@code className} using the current thread's context class loader. This
566      * implementation supports the syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
567      * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
568      *
569      * @param className the class name
570      * @param initialize whether the class must be initialized
571      * @return the class represented by {@code className} using the current thread's context class loader
572      * @throws NullPointerException if the className is null
573      * @throws ClassNotFoundException if the class is not found
574      */
575     public static Class<?> getClass(final String className, final boolean initialize) throws ClassNotFoundException {
576         final ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
577         final ClassLoader loader = contextCL == null ? ClassUtils.class.getClassLoader() : contextCL;
578         return getClass(loader, className, initialize);
579     }
580 
581     /**
582      * Delegates to {@link Class#getComponentType()} using generics.
583      *
584      * @param <T> The array class type.
585      * @param cls A class or null.
586      * @return The array component type or null.
587      * @see Class#getComponentType()
588      * @since 3.13.0
589      */
590     @SuppressWarnings("unchecked")
591     public static <T> Class<T> getComponentType(final Class<T[]> cls) {
592         return cls == null ? null : (Class<T>) cls.getComponentType();
593     }
594 
595     /**
596      * Null-safe version of {@code cls.getName()}
597      *
598      * @param cls the class for which to get the class name; may be null
599      * @return the class name or the empty string in case the argument is {@code null}
600      * @since 3.7
601      * @see Class#getSimpleName()
602      */
603     public static String getName(final Class<?> cls) {
604         return getName(cls, StringUtils.EMPTY);
605     }
606 
607     /**
608      * Null-safe version of {@code cls.getName()}
609      *
610      * @param cls the class for which to get the class name; may be null
611      * @param valueIfNull the return value if the argument {@code cls} is {@code null}
612      * @return the class name or {@code valueIfNull}
613      * @since 3.7
614      * @see Class#getName()
615      */
616     public static String getName(final Class<?> cls, final String valueIfNull) {
617         return cls == null ? valueIfNull : cls.getName();
618     }
619 
620     /**
621      * Null-safe version of {@code object.getClass().getName()}
622      *
623      * @param object the object for which to get the class name; may be null
624      * @return the class name or the empty String
625      * @since 3.7
626      * @see Class#getSimpleName()
627      */
628     public static String getName(final Object object) {
629         return getName(object, StringUtils.EMPTY);
630     }
631 
632     /**
633      * Null-safe version of {@code object.getClass().getSimpleName()}
634      *
635      * @param object the object for which to get the class name; may be null
636      * @param valueIfNull the value to return if {@code object} is {@code null}
637      * @return the class name or {@code valueIfNull}
638      * @since 3.0
639      * @see Class#getName()
640      */
641     public static String getName(final Object object, final String valueIfNull) {
642         return object == null ? valueIfNull : object.getClass().getName();
643     }
644 
645     /**
646      * Gets the package name from the canonical name of a {@link Class}.
647      *
648      * @param cls the class to get the package name for, may be {@code null}.
649      * @return the package name or an empty string
650      * @since 2.4
651      */
652     public static String getPackageCanonicalName(final Class<?> cls) {
653         if (cls == null) {
654             return StringUtils.EMPTY;
655         }
656         return getPackageCanonicalName(cls.getName());
657     }
658 
659     /**
660      * Gets the package name from the class name of an {@link Object}.
661      *
662      * @param object the class to get the package name for, may be null
663      * @param valueIfNull the value to return if null
664      * @return the package name of the object, or the null value
665      * @since 2.4
666      */
667     public static String getPackageCanonicalName(final Object object, final String valueIfNull) {
668         if (object == null) {
669             return valueIfNull;
670         }
671         return getPackageCanonicalName(object.getClass().getName());
672     }
673 
674     /**
675      * Gets the package name from the class name.
676      *
677      * <p>
678      * The string passed in is assumed to be a class name - it is not checked.
679      * </p>
680      * <p>
681      * If the class is in the default package, return an empty string.
682      * </p>
683      *
684      * @param name the name to get the package name for, may be {@code null}
685      * @return the package name or an empty string
686      * @since 2.4
687      */
688     public static String getPackageCanonicalName(final String name) {
689         return getPackageName(getCanonicalName(name));
690     }
691 
692     /**
693      * Gets the package name of a {@link Class}.
694      *
695      * @param cls the class to get the package name for, may be {@code null}.
696      * @return the package name or an empty string
697      */
698     public static String getPackageName(final Class<?> cls) {
699         if (cls == null) {
700             return StringUtils.EMPTY;
701         }
702         return getPackageName(cls.getName());
703     }
704 
705     /**
706      * Gets the package name of an {@link Object}.
707      *
708      * @param object the class to get the package name for, may be null
709      * @param valueIfNull the value to return if null
710      * @return the package name of the object, or the null value
711      */
712     public static String getPackageName(final Object object, final String valueIfNull) {
713         if (object == null) {
714             return valueIfNull;
715         }
716         return getPackageName(object.getClass());
717     }
718 
719     /**
720      * Gets the package name from a {@link String}.
721      *
722      * <p>
723      * The string passed in is assumed to be a class name - it is not checked.
724      * </p>
725      * <p>
726      * If the class is unpackaged, return an empty string.
727      * </p>
728      *
729      * @param className the className to get the package name for, may be {@code null}
730      * @return the package name or an empty string
731      */
732     public static String getPackageName(String className) {
733         if (StringUtils.isEmpty(className)) {
734             return StringUtils.EMPTY;
735         }
736 
737         // Strip array encoding
738         while (className.charAt(0) == '[') {
739             className = className.substring(1);
740         }
741         // Strip Object type encoding
742         if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
743             className = className.substring(1);
744         }
745 
746         final int i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
747         if (i == -1) {
748             return StringUtils.EMPTY;
749         }
750         return className.substring(0, i);
751     }
752 
753     /**
754      * Returns the desired Method much like {@code Class.getMethod}, however it ensures that the returned Method is from a
755      * public class or interface and not from an anonymous inner class. This means that the Method is invokable and doesn't
756      * fall foul of Java bug <a href="https://bugs.java.com/bugdatabase/view_bug.do?bug_id=4071957">4071957</a>).
757      *
758      * <pre>
759      *  <code>Set set = Collections.unmodifiableSet(...);
760      *  Method method = ClassUtils.getPublicMethod(set.getClass(), "isEmpty",  new Class[0]);
761      *  Object result = method.invoke(set, new Object[]);</code>
762      * </pre>
763      *
764      * @param cls the class to check, not null
765      * @param methodName the name of the method
766      * @param parameterTypes the list of parameters
767      * @return the method
768      * @throws NullPointerException if the class is null
769      * @throws SecurityException if a security violation occurred
770      * @throws NoSuchMethodException if the method is not found in the given class or if the method doesn't conform with the
771      *         requirements
772      */
773     public static Method getPublicMethod(final Class<?> cls, final String methodName, final Class<?>... parameterTypes) throws NoSuchMethodException {
774 
775         final Method declaredMethod = cls.getMethod(methodName, parameterTypes);
776         if (isPublic(declaredMethod.getDeclaringClass())) {
777             return declaredMethod;
778         }
779 
780         final List<Class<?>> candidateClasses = new ArrayList<>(getAllInterfaces(cls));
781         candidateClasses.addAll(getAllSuperclasses(cls));
782 
783         for (final Class<?> candidateClass : candidateClasses) {
784             if (!isPublic(candidateClass)) {
785                 continue;
786             }
787             final Method candidateMethod;
788             try {
789                 candidateMethod = candidateClass.getMethod(methodName, parameterTypes);
790             } catch (final NoSuchMethodException ex) {
791                 continue;
792             }
793             if (Modifier.isPublic(candidateMethod.getDeclaringClass().getModifiers())) {
794                 return candidateMethod;
795             }
796         }
797 
798         throw new NoSuchMethodException("Can't find a public method for " + methodName + " " + ArrayUtils.toString(parameterTypes));
799     }
800 
801     /**
802      * Gets the canonical name minus the package name from a {@link Class}.
803      *
804      * @param cls the class for which to get the short canonical class name; may be null
805      * @return the canonical name without the package name or an empty string
806      * @since 2.4
807      * @see Class#getCanonicalName()
808      */
809     public static String getShortCanonicalName(final Class<?> cls) {
810         return cls == null ? StringUtils.EMPTY : getShortCanonicalName(cls.getCanonicalName());
811     }
812 
813     /**
814      * Gets the canonical name minus the package name for an {@link Object}.
815      *
816      * @param object the class to get the short name for, may be null
817      * @param valueIfNull the value to return if null
818      * @return the canonical name of the object without the package name, or the null value
819      * @since 2.4
820      * @see Class#getCanonicalName()
821      */
822     public static String getShortCanonicalName(final Object object, final String valueIfNull) {
823         return object == null ? valueIfNull : getShortCanonicalName(object.getClass().getCanonicalName());
824     }
825 
826     /**
827      * Gets the canonical name minus the package name from a String.
828      *
829      * <p>
830      * The string passed in is assumed to be a class name - it is not checked.
831      * </p>
832      *
833      * <p>
834      * Note that this method is mainly designed to handle the arrays and primitives properly. If the class is an inner class
835      * then the result value will not contain the outer classes. This way the behavior of this method is different from
836      * {@link #getShortClassName(String)}. The argument in that case is class name and not canonical name and the return
837      * value retains the outer classes.
838      * </p>
839      *
840      * <p>
841      * Note that there is no way to reliably identify the part of the string representing the package hierarchy and the part
842      * that is the outer class or classes in case of an inner class. Trying to find the class would require reflective call
843      * and the class itself may not even be on the class path. Relying on the fact that class names start with capital
844      * letter and packages with lower case is heuristic.
845      * </p>
846      *
847      * <p>
848      * It is recommended to use {@link #getShortClassName(String)} for cases when the class is an inner class and use this
849      * method for cases it is designed for.
850      * </p>
851      *
852      * <table>
853      * <caption>Examples</caption>
854      * <tr>
855      * <td>return value</td>
856      * <td>input</td>
857      * </tr>
858      * <tr>
859      * <td>{@code ""}</td>
860      * <td>{@code (String)null}</td>
861      * </tr>
862      * <tr>
863      * <td>{@code "Map.Entry"}</td>
864      * <td>{@code java.util.Map.Entry.class.getName()}</td>
865      * </tr>
866      * <tr>
867      * <td>{@code "Entry"}</td>
868      * <td>{@code java.util.Map.Entry.class.getCanonicalName()}</td>
869      * </tr>
870      * <tr>
871      * <td>{@code "ClassUtils"}</td>
872      * <td>{@code "org.apache.commons.lang3.ClassUtils"}</td>
873      * </tr>
874      * <tr>
875      * <td>{@code "ClassUtils[]"}</td>
876      * <td>{@code "[Lorg.apache.commons.lang3.ClassUtils;"}</td>
877      * </tr>
878      * <tr>
879      * <td>{@code "ClassUtils[][]"}</td>
880      * <td>{@code "[[Lorg.apache.commons.lang3.ClassUtils;"}</td>
881      * </tr>
882      * <tr>
883      * <td>{@code "ClassUtils[]"}</td>
884      * <td>{@code "org.apache.commons.lang3.ClassUtils[]"}</td>
885      * </tr>
886      * <tr>
887      * <td>{@code "ClassUtils[][]"}</td>
888      * <td>{@code "org.apache.commons.lang3.ClassUtils[][]"}</td>
889      * </tr>
890      * <tr>
891      * <td>{@code "int[]"}</td>
892      * <td>{@code "[I"}</td>
893      * </tr>
894      * <tr>
895      * <td>{@code "int[]"}</td>
896      * <td>{@code int[].class.getCanonicalName()}</td>
897      * </tr>
898      * <tr>
899      * <td>{@code "int[]"}</td>
900      * <td>{@code int[].class.getName()}</td>
901      * </tr>
902      * <tr>
903      * <td>{@code "int[][]"}</td>
904      * <td>{@code "[[I"}</td>
905      * </tr>
906      * <tr>
907      * <td>{@code "int[]"}</td>
908      * <td>{@code "int[]"}</td>
909      * </tr>
910      * <tr>
911      * <td>{@code "int[][]"}</td>
912      * <td>{@code "int[][]"}</td>
913      * </tr>
914      * </table>
915      *
916      * @param canonicalName the class name to get the short name for
917      * @return the canonical name of the class without the package name or an empty string
918      * @since 2.4
919      */
920     public static String getShortCanonicalName(final String canonicalName) {
921         return getShortClassName(getCanonicalName(canonicalName));
922     }
923 
924     /**
925      * Gets the class name minus the package name from a {@link Class}.
926      *
927      * <p>
928      * This method simply gets the name using {@code Class.getName()} and then calls {@link #getShortClassName(Class)}. See
929      * relevant notes there.
930      * </p>
931      *
932      * @param cls the class to get the short name for.
933      * @return the class name without the package name or an empty string. If the class is an inner class then the returned
934      *         value will contain the outer class or classes separated with {@code .} (dot) character.
935      */
936     public static String getShortClassName(final Class<?> cls) {
937         if (cls == null) {
938             return StringUtils.EMPTY;
939         }
940         return getShortClassName(cls.getName());
941     }
942 
943     /**
944      * Gets the class name of the {@code object} without the package name or names.
945      *
946      * <p>
947      * The method looks up the class of the object and then converts the name of the class invoking
948      * {@link #getShortClassName(Class)} (see relevant notes there).
949      * </p>
950      *
951      * @param object the class to get the short name for, may be {@code null}
952      * @param valueIfNull the value to return if the object is {@code null}
953      * @return the class name of the object without the package name, or {@code valueIfNull} if the argument {@code object}
954      *         is {@code null}
955      */
956     public static String getShortClassName(final Object object, final String valueIfNull) {
957         if (object == null) {
958             return valueIfNull;
959         }
960         return getShortClassName(object.getClass());
961     }
962 
963     /**
964      * Gets the class name minus the package name from a String.
965      *
966      * <p>
967      * The string passed in is assumed to be a class name - it is not checked. The string has to be formatted the way as the
968      * JDK method {@code Class.getName()} returns it, and not the usual way as we write it, for example in import
969      * statements, or as it is formatted by {@code Class.getCanonicalName()}.
970      * </p>
971      *
972      * <p>
973      * The difference is is significant only in case of classes that are inner classes of some other classes. In this case
974      * the separator between the outer and inner class (possibly on multiple hierarchy level) has to be {@code $} (dollar
975      * sign) and not {@code .} (dot), as it is returned by {@code Class.getName()}
976      * </p>
977      *
978      * <p>
979      * Note that this method is called from the {@link #getShortClassName(Class)} method using the string returned by
980      * {@code Class.getName()}.
981      * </p>
982      *
983      * <p>
984      * Note that this method differs from {@link #getSimpleName(Class)} in that this will return, for example
985      * {@code "Map.Entry"} whilst the {@code java.lang.Class} variant will simply return {@code "Entry"}. In this example
986      * the argument {@code className} is the string {@code java.util.Map$Entry} (note the {@code $} sign.
987      * </p>
988      *
989      * @param className the className to get the short name for. It has to be formatted as returned by
990      *        {@code Class.getName()} and not {@code Class.getCanonicalName()}
991      * @return the class name of the class without the package name or an empty string. If the class is an inner class then
992      *         value contains the outer class or classes and the separator is replaced to be {@code .} (dot) character.
993      */
994     public static String getShortClassName(String className) {
995         if (StringUtils.isEmpty(className)) {
996             return StringUtils.EMPTY;
997         }
998 
999         final StringBuilder arrayPrefix = new StringBuilder();
1000 
1001         // Handle array encoding
1002         if (className.startsWith("[")) {
1003             while (className.charAt(0) == '[') {
1004                 className = className.substring(1);
1005                 arrayPrefix.append("[]");
1006             }
1007             // Strip Object type encoding
1008             if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
1009                 className = className.substring(1, className.length() - 1);
1010             }
1011 
1012             if (reverseAbbreviationMap.containsKey(className)) {
1013                 className = reverseAbbreviationMap.get(className);
1014             }
1015         }
1016 
1017         final int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
1018         final int innerIdx = className.indexOf(INNER_CLASS_SEPARATOR_CHAR, lastDotIdx == -1 ? 0 : lastDotIdx + 1);
1019         String out = className.substring(lastDotIdx + 1);
1020         if (innerIdx != -1) {
1021             out = out.replace(INNER_CLASS_SEPARATOR_CHAR, PACKAGE_SEPARATOR_CHAR);
1022         }
1023         return out + arrayPrefix;
1024     }
1025 
1026     /**
1027      * Null-safe version of {@code cls.getSimpleName()}
1028      *
1029      * @param cls the class for which to get the simple name; may be null
1030      * @return the simple class name or the empty string in case the argument is {@code null}
1031      * @since 3.0
1032      * @see Class#getSimpleName()
1033      */
1034     public static String getSimpleName(final Class<?> cls) {
1035         return getSimpleName(cls, StringUtils.EMPTY);
1036     }
1037 
1038     /**
1039      * Null-safe version of {@code cls.getSimpleName()}
1040      *
1041      * @param cls the class for which to get the simple name; may be null
1042      * @param valueIfNull the value to return if null
1043      * @return the simple class name or {@code valueIfNull} if the argument {@code cls} is {@code null}
1044      * @since 3.0
1045      * @see Class#getSimpleName()
1046      */
1047     public static String getSimpleName(final Class<?> cls, final String valueIfNull) {
1048         return cls == null ? valueIfNull : cls.getSimpleName();
1049     }
1050 
1051     /**
1052      * Null-safe version of {@code object.getClass().getSimpleName()}
1053      *
1054      * <p>
1055      * It is to note that this method is overloaded and in case the argument {@code object} is a {@link Class} object then
1056      * the {@link #getSimpleName(Class)} will be invoked. If this is a significant possibility then the caller should check
1057      * this case and call {@code
1058      * getSimpleName(Class.class)} or just simply use the string literal {@code "Class"}, which is the result of the method
1059      * in that case.
1060      * </p>
1061      *
1062      * @param object the object for which to get the simple class name; may be null
1063      * @return the simple class name or the empty string in case the argument is {@code null}
1064      * @since 3.7
1065      * @see Class#getSimpleName()
1066      */
1067     public static String getSimpleName(final Object object) {
1068         return getSimpleName(object, StringUtils.EMPTY);
1069     }
1070 
1071     /**
1072      * Null-safe version of {@code object.getClass().getSimpleName()}
1073      *
1074      * @param object the object for which to get the simple class name; may be null
1075      * @param valueIfNull the value to return if {@code object} is {@code null}
1076      * @return the simple class name or {@code valueIfNull} if the argument {@code object} is {@code null}
1077      * @since 3.0
1078      * @see Class#getSimpleName()
1079      */
1080     public static String getSimpleName(final Object object, final String valueIfNull) {
1081         return object == null ? valueIfNull : object.getClass().getSimpleName();
1082     }
1083 
1084     /**
1085      * Gets an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order,
1086      * excluding interfaces.
1087      *
1088      * @param type the type to get the class hierarchy from
1089      * @return Iterable an Iterable over the class hierarchy of the given class
1090      * @since 3.2
1091      */
1092     public static Iterable<Class<?>> hierarchy(final Class<?> type) {
1093         return hierarchy(type, Interfaces.EXCLUDE);
1094     }
1095 
1096     /**
1097      * Gets an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order.
1098      *
1099      * @param type the type to get the class hierarchy from
1100      * @param interfacesBehavior switch indicating whether to include or exclude interfaces
1101      * @return Iterable an Iterable over the class hierarchy of the given class
1102      * @since 3.2
1103      */
1104     public static Iterable<Class<?>> hierarchy(final Class<?> type, final Interfaces interfacesBehavior) {
1105         final Iterable<Class<?>> classes = () -> {
1106             final MutableObject<Class<?>> next = new MutableObject<>(type);
1107             return new Iterator<Class<?>>() {
1108 
1109                 @Override
1110                 public boolean hasNext() {
1111                     return next.getValue() != null;
1112                 }
1113 
1114                 @Override
1115                 public Class<?> next() {
1116                     final Class<?> result = next.getValue();
1117                     next.setValue(result.getSuperclass());
1118                     return result;
1119                 }
1120 
1121                 @Override
1122                 public void remove() {
1123                     throw new UnsupportedOperationException();
1124                 }
1125 
1126             };
1127         };
1128         if (interfacesBehavior != Interfaces.INCLUDE) {
1129             return classes;
1130         }
1131         return () -> {
1132             final Set<Class<?>> seenInterfaces = new HashSet<>();
1133             final Iterator<Class<?>> wrapped = classes.iterator();
1134 
1135             return new Iterator<Class<?>>() {
1136                 Iterator<Class<?>> interfaces = Collections.emptyIterator();
1137 
1138                 @Override
1139                 public boolean hasNext() {
1140                     return interfaces.hasNext() || wrapped.hasNext();
1141                 }
1142 
1143                 @Override
1144                 public Class<?> next() {
1145                     if (interfaces.hasNext()) {
1146                         final Class<?> nextInterface = interfaces.next();
1147                         seenInterfaces.add(nextInterface);
1148                         return nextInterface;
1149                     }
1150                     final Class<?> nextSuperclass = wrapped.next();
1151                     final Set<Class<?>> currentInterfaces = new LinkedHashSet<>();
1152                     walkInterfaces(currentInterfaces, nextSuperclass);
1153                     interfaces = currentInterfaces.iterator();
1154                     return nextSuperclass;
1155                 }
1156 
1157                 @Override
1158                 public void remove() {
1159                     throw new UnsupportedOperationException();
1160                 }
1161 
1162                 private void walkInterfaces(final Set<Class<?>> addTo, final Class<?> c) {
1163                     for (final Class<?> iface : c.getInterfaces()) {
1164                         if (!seenInterfaces.contains(iface)) {
1165                             addTo.add(iface);
1166                         }
1167                         walkInterfaces(addTo, iface);
1168                     }
1169                 }
1170 
1171             };
1172         };
1173     }
1174 
1175     /**
1176      * Checks if one {@link Class} can be assigned to a variable of another {@link Class}.
1177      *
1178      * <p>
1179      * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1180      * primitive classes and {@code null}s.
1181      * </p>
1182      *
1183      * <p>
1184      * Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result
1185      * for these cases.
1186      * </p>
1187      *
1188      * <p>
1189      * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1190      * and the toClass is non-primitive.
1191      * </p>
1192      *
1193      * <p>
1194      * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1195      * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1196      * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1197      * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1198      * </p>
1199      *
1200      * <p>
1201      * <strong>Since Lang 3.0,</strong> this method will default behavior for calculating assignability between primitive
1202      * and wrapper types <em>corresponding to the running Java version</em>; i.e. autoboxing will be the default behavior in
1203      * VMs running Java versions &gt; 1.5.
1204      * </p>
1205      *
1206      * @param cls the Class to check, may be null
1207      * @param toClass the Class to try to assign into, returns false if null
1208      * @return {@code true} if assignment possible
1209      */
1210     public static boolean isAssignable(final Class<?> cls, final Class<?> toClass) {
1211         return isAssignable(cls, toClass, true);
1212     }
1213 
1214     /**
1215      * Checks if one {@link Class} can be assigned to a variable of another {@link Class}.
1216      *
1217      * <p>
1218      * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1219      * primitive classes and {@code null}s.
1220      * </p>
1221      *
1222      * <p>
1223      * Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result
1224      * for these cases.
1225      * </p>
1226      *
1227      * <p>
1228      * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1229      * and the toClass is non-primitive.
1230      * </p>
1231      *
1232      * <p>
1233      * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1234      * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1235      * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1236      * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1237      * </p>
1238      *
1239      * @param cls the Class to check, may be null
1240      * @param toClass the Class to try to assign into, returns false if null
1241      * @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers
1242      * @return {@code true} if assignment possible
1243      */
1244     public static boolean isAssignable(Class<?> cls, final Class<?> toClass, final boolean autoboxing) {
1245         if (toClass == null) {
1246             return false;
1247         }
1248         // have to check for null, as isAssignableFrom doesn't
1249         if (cls == null) {
1250             return !toClass.isPrimitive();
1251         }
1252         // autoboxing:
1253         if (autoboxing) {
1254             if (cls.isPrimitive() && !toClass.isPrimitive()) {
1255                 cls = primitiveToWrapper(cls);
1256                 if (cls == null) {
1257                     return false;
1258                 }
1259             }
1260             if (toClass.isPrimitive() && !cls.isPrimitive()) {
1261                 cls = wrapperToPrimitive(cls);
1262                 if (cls == null) {
1263                     return false;
1264                 }
1265             }
1266         }
1267         if (cls.equals(toClass)) {
1268             return true;
1269         }
1270         if (cls.isPrimitive()) {
1271             if (!toClass.isPrimitive()) {
1272                 return false;
1273             }
1274             if (Integer.TYPE.equals(cls)) {
1275                 return Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
1276             }
1277             if (Long.TYPE.equals(cls)) {
1278                 return Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
1279             }
1280             if (Boolean.TYPE.equals(cls)) {
1281                 return false;
1282             }
1283             if (Double.TYPE.equals(cls)) {
1284                 return false;
1285             }
1286             if (Float.TYPE.equals(cls)) {
1287                 return Double.TYPE.equals(toClass);
1288             }
1289             if (Character.TYPE.equals(cls)  || Short.TYPE.equals(cls)) {
1290                 return Integer.TYPE.equals(toClass) || Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
1291             }
1292             if (Byte.TYPE.equals(cls)) {
1293                 return Short.TYPE.equals(toClass) || Integer.TYPE.equals(toClass) || Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass)
1294                     || Double.TYPE.equals(toClass);
1295             }
1296             // should never get here
1297             return false;
1298         }
1299         return toClass.isAssignableFrom(cls);
1300     }
1301 
1302     /**
1303      * Checks if an array of Classes can be assigned to another array of Classes.
1304      *
1305      * <p>
1306      * This method calls {@link #isAssignable(Class, Class) isAssignable} for each Class pair in the input arrays. It can be
1307      * used to check if a set of arguments (the first parameter) are suitably compatible with a set of method parameter
1308      * types (the second parameter).
1309      * </p>
1310      *
1311      * <p>
1312      * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1313      * primitive classes and {@code null}s.
1314      * </p>
1315      *
1316      * <p>
1317      * Primitive widenings allow an int to be assigned to a {@code long}, {@code float} or {@code double}. This method
1318      * returns the correct result for these cases.
1319      * </p>
1320      *
1321      * <p>
1322      * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1323      * and the toClass is non-primitive.
1324      * </p>
1325      *
1326      * <p>
1327      * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1328      * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1329      * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1330      * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1331      * </p>
1332      *
1333      * <p>
1334      * <strong>Since Lang 3.0,</strong> this method will default behavior for calculating assignability between primitive
1335      * and wrapper types <em>corresponding to the running Java version</em>; i.e. autoboxing will be the default behavior in
1336      * VMs running Java versions &gt; 1.5.
1337      * </p>
1338      *
1339      * @param classArray the array of Classes to check, may be {@code null}
1340      * @param toClassArray the array of Classes to try to assign into, may be {@code null}
1341      * @return {@code true} if assignment possible
1342      */
1343     public static boolean isAssignable(final Class<?>[] classArray, final Class<?>... toClassArray) {
1344         return isAssignable(classArray, toClassArray, true);
1345     }
1346 
1347     /**
1348      * Checks if an array of Classes can be assigned to another array of Classes.
1349      *
1350      * <p>
1351      * This method calls {@link #isAssignable(Class, Class) isAssignable} for each Class pair in the input arrays. It can be
1352      * used to check if a set of arguments (the first parameter) are suitably compatible with a set of method parameter
1353      * types (the second parameter).
1354      * </p>
1355      *
1356      * <p>
1357      * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1358      * primitive classes and {@code null}s.
1359      * </p>
1360      *
1361      * <p>
1362      * Primitive widenings allow an int to be assigned to a {@code long}, {@code float} or {@code double}. This method
1363      * returns the correct result for these cases.
1364      * </p>
1365      *
1366      * <p>
1367      * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1368      * and the toClass is non-primitive.
1369      * </p>
1370      *
1371      * <p>
1372      * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1373      * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1374      * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1375      * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1376      * </p>
1377      *
1378      * @param classArray the array of Classes to check, may be {@code null}
1379      * @param toClassArray the array of Classes to try to assign into, may be {@code null}
1380      * @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers
1381      * @return {@code true} if assignment possible
1382      */
1383     public static boolean isAssignable(Class<?>[] classArray, Class<?>[] toClassArray, final boolean autoboxing) {
1384         if (!ArrayUtils.isSameLength(classArray, toClassArray)) {
1385             return false;
1386         }
1387         if (classArray == null) {
1388             classArray = ArrayUtils.EMPTY_CLASS_ARRAY;
1389         }
1390         if (toClassArray == null) {
1391             toClassArray = ArrayUtils.EMPTY_CLASS_ARRAY;
1392         }
1393         for (int i = 0; i < classArray.length; i++) {
1394             if (!isAssignable(classArray[i], toClassArray[i], autoboxing)) {
1395                 return false;
1396             }
1397         }
1398         return true;
1399     }
1400 
1401     /**
1402      * Is the specified class an inner class or static nested class.
1403      *
1404      * @param cls the class to check, may be null
1405      * @return {@code true} if the class is an inner or static nested class, false if not or {@code null}
1406      */
1407     public static boolean isInnerClass(final Class<?> cls) {
1408         return cls != null && cls.getEnclosingClass() != null;
1409     }
1410 
1411     /**
1412      * Tests whether a {@link Class} is public.
1413      * @param cls Class to test.
1414      * @return {@code true} if {@code cls} is public.
1415      * @since 3.13.0
1416      */
1417     public static boolean isPublic(final Class<?> cls) {
1418         return Modifier.isPublic(cls.getModifiers());
1419     }
1420     /**
1421      * Returns whether the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte},
1422      * {@link Character}, {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1423      *
1424      * @param type The class to query or null.
1425      * @return true if the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte},
1426      *         {@link Character}, {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1427      * @since 3.1
1428      */
1429     public static boolean isPrimitiveOrWrapper(final Class<?> type) {
1430         if (type == null) {
1431             return false;
1432         }
1433         return type.isPrimitive() || isPrimitiveWrapper(type);
1434     }
1435 
1436     /**
1437      * Returns whether the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
1438      * {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1439      *
1440      * @param type The class to query or null.
1441      * @return true if the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
1442      *         {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1443      * @since 3.1
1444      */
1445     public static boolean isPrimitiveWrapper(final Class<?> type) {
1446         return wrapperPrimitiveMap.containsKey(type);
1447     }
1448 
1449     /**
1450      * Converts the specified array of primitive Class objects to an array of its corresponding wrapper Class objects.
1451      *
1452      * @param classes the class array to convert, may be null or empty
1453      * @return an array which contains for each given class, the wrapper class or the original class if class is not a
1454      *         primitive. {@code null} if null input. Empty array if an empty array passed in.
1455      * @since 2.1
1456      */
1457     public static Class<?>[] primitivesToWrappers(final Class<?>... classes) {
1458         if (classes == null) {
1459             return null;
1460         }
1461 
1462         if (classes.length == 0) {
1463             return classes;
1464         }
1465 
1466         final Class<?>[] convertedClasses = new Class[classes.length];
1467         Arrays.setAll(convertedClasses, i -> primitiveToWrapper(classes[i]));
1468         return convertedClasses;
1469     }
1470 
1471     /**
1472      * Converts the specified primitive Class object to its corresponding wrapper Class object.
1473      *
1474      * <p>
1475      * NOTE: From v2.2, this method handles {@code Void.TYPE}, returning {@code Void.TYPE}.
1476      * </p>
1477      *
1478      * @param cls the class to convert, may be null
1479      * @return the wrapper class for {@code cls} or {@code cls} if {@code cls} is not a primitive. {@code null} if null
1480      *         input.
1481      * @since 2.1
1482      */
1483     public static Class<?> primitiveToWrapper(final Class<?> cls) {
1484         Class<?> convertedClass = cls;
1485         if (cls != null && cls.isPrimitive()) {
1486             convertedClass = primitiveWrapperMap.get(cls);
1487         }
1488         return convertedClass;
1489     }
1490 
1491     /**
1492      * Converts a class name to a JLS style class name.
1493      *
1494      * @param className the class name
1495      * @return the converted name
1496      * @throws NullPointerException if the className is null
1497      */
1498     private static String toCanonicalName(final String className) {
1499         String canonicalName = StringUtils.deleteWhitespace(className);
1500         Objects.requireNonNull(canonicalName, "className");
1501         if (canonicalName.endsWith("[]")) {
1502             final StringBuilder classNameBuffer = new StringBuilder();
1503             while (canonicalName.endsWith("[]")) {
1504                 canonicalName = canonicalName.substring(0, canonicalName.length() - 2);
1505                 classNameBuffer.append("[");
1506             }
1507             final String abbreviation = abbreviationMap.get(canonicalName);
1508             if (abbreviation != null) {
1509                 classNameBuffer.append(abbreviation);
1510             } else {
1511                 classNameBuffer.append("L").append(canonicalName).append(";");
1512             }
1513             canonicalName = classNameBuffer.toString();
1514         }
1515         return canonicalName;
1516     }
1517 
1518     /**
1519      * Converts an array of {@link Object} in to an array of {@link Class} objects. If any of these objects is null, a null
1520      * element will be inserted into the array.
1521      *
1522      * <p>
1523      * This method returns {@code null} for a {@code null} input array.
1524      * </p>
1525      *
1526      * @param array an {@link Object} array
1527      * @return a {@link Class} array, {@code null} if null array input
1528      * @since 2.4
1529      */
1530     public static Class<?>[] toClass(final Object... array) {
1531         if (array == null) {
1532             return null;
1533         }
1534         if (array.length == 0) {
1535             return ArrayUtils.EMPTY_CLASS_ARRAY;
1536         }
1537         final Class<?>[] classes = new Class[array.length];
1538         Arrays.setAll(classes, i -> array[i] == null ? null : array[i].getClass());
1539         return classes;
1540     }
1541 
1542     /**
1543      * Decides if the part that was just copied to its destination location in the work array can be kept as it was copied
1544      * or must be abbreviated. It must be kept when the part is the last one, which is the simple name of the class. In this
1545      * case the {@code source} index, from where the characters are copied points one position after the last character,
1546      * a.k.a. {@code source ==
1547      * originalLength}
1548      *
1549      * <p>
1550      * If the part is not the last one then it can be kept unabridged if the number of the characters copied so far plus the
1551      * character that are to be copied is less than or equal to the desired length.
1552      * </p>
1553      *
1554      * @param runAheadTarget the target index (where the characters were copied to) pointing after the last character copied
1555      *        when the current part was copied
1556      * @param source the source index (where the characters were copied from) pointing after the last character copied when
1557      *        the current part was copied
1558      * @param originalLength the original length of the class full name, which is abbreviated
1559      * @param desiredLength the desired length of the abbreviated class name
1560      * @return {@code true} if it can be kept in its original length {@code false} if the current part has to be abbreviated
1561      *         and
1562      */
1563     private static boolean useFull(final int runAheadTarget, final int source, final int originalLength, final int desiredLength) {
1564         return source >= originalLength || runAheadTarget + originalLength - source <= desiredLength;
1565     }
1566 
1567     /**
1568      * Converts the specified array of wrapper Class objects to an array of its corresponding primitive Class objects.
1569      *
1570      * <p>
1571      * This method invokes {@code wrapperToPrimitive()} for each element of the passed in array.
1572      * </p>
1573      *
1574      * @param classes the class array to convert, may be null or empty
1575      * @return an array which contains for each given class, the primitive class or <b>null</b> if the original class is not
1576      *         a wrapper class. {@code null} if null input. Empty array if an empty array passed in.
1577      * @see #wrapperToPrimitive(Class)
1578      * @since 2.4
1579      */
1580     public static Class<?>[] wrappersToPrimitives(final Class<?>... classes) {
1581         if (classes == null) {
1582             return null;
1583         }
1584 
1585         if (classes.length == 0) {
1586             return classes;
1587         }
1588 
1589         final Class<?>[] convertedClasses = new Class[classes.length];
1590         Arrays.setAll(convertedClasses, i -> wrapperToPrimitive(classes[i]));
1591         return convertedClasses;
1592     }
1593 
1594     /**
1595      * Converts the specified wrapper class to its corresponding primitive class.
1596      *
1597      * <p>
1598      * This method is the counter part of {@code primitiveToWrapper()}. If the passed in class is a wrapper class for a
1599      * primitive type, this primitive type will be returned (e.g. {@code Integer.TYPE} for {@code Integer.class}). For other
1600      * classes, or if the parameter is <b>null</b>, the return value is <b>null</b>.
1601      * </p>
1602      *
1603      * @param cls the class to convert, may be <b>null</b>
1604      * @return the corresponding primitive type if {@code cls} is a wrapper class, <b>null</b> otherwise
1605      * @see #primitiveToWrapper(Class)
1606      * @since 2.4
1607      */
1608     public static Class<?> wrapperToPrimitive(final Class<?> cls) {
1609         return wrapperPrimitiveMap.get(cls);
1610     }
1611 
1612     /**
1613      * ClassUtils instances should NOT be constructed in standard programming. Instead, the class should be used as
1614      * {@code ClassUtils.getShortClassName(cls)}.
1615      *
1616      * <p>
1617      * This constructor is public to permit tools that require a JavaBean instance to operate.
1618      * </p>
1619      */
1620     public ClassUtils() {
1621     }
1622 
1623 }