001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      https://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.lang3;
018
019import java.lang.reflect.Method;
020import java.lang.reflect.Modifier;
021import java.util.ArrayList;
022import java.util.Arrays;
023import java.util.Collections;
024import java.util.Comparator;
025import java.util.HashMap;
026import java.util.HashSet;
027import java.util.Iterator;
028import java.util.LinkedHashSet;
029import java.util.List;
030import java.util.Map;
031import java.util.Objects;
032import java.util.Set;
033import java.util.concurrent.atomic.AtomicReference;
034import java.util.stream.Collectors;
035
036/**
037 * Operates on classes without using reflection.
038 *
039 * <p>
040 * This class handles invalid {@code null} inputs as best it can. Each method documents its behavior in more detail.
041 * </p>
042 *
043 * <p>
044 * The notion of a {@code canonical name} includes the human readable name for the type, for example {@code int[]}. The
045 * non-canonical method variants work with the JVM names, such as {@code [I}.
046 * </p>
047 *
048 * @since 2.0
049 */
050public class ClassUtils {
051
052    /**
053     * Inclusivity literals for {@link #hierarchy(Class, Interfaces)}.
054     *
055     * @since 3.2
056     */
057    public enum Interfaces {
058
059        /** Includes interfaces. */
060        INCLUDE,
061
062        /** Excludes interfaces. */
063        EXCLUDE
064    }
065
066    /**
067     * The maximum number of array dimensions.
068     */
069    private static final int MAX_DIMENSIONS = 255;
070
071    private static final Comparator<Class<?>> COMPARATOR = (o1, o2) -> Objects.compare(getName(o1), getName(o2), String::compareTo);
072
073    /**
074     * The package separator character: {@code '&#x2e;' == {@value}}.
075     */
076    public static final char PACKAGE_SEPARATOR_CHAR = '.';
077
078    /**
079     * The package separator String: {@code "&#x2e;"}.
080     */
081    public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);
082
083    /**
084     * The inner class separator character: {@code '$' == {@value}}.
085     */
086    public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
087
088    /**
089     * The inner class separator String: {@code "$"}.
090     */
091    public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
092
093    /**
094     * Maps names of primitives to their corresponding primitive {@link Class}es.
095     */
096    private static final Map<String, Class<?>> NAME_PRIMITIVE_MAP = new HashMap<>();
097
098    static {
099        NAME_PRIMITIVE_MAP.put(Boolean.TYPE.getName(), Boolean.TYPE);
100        NAME_PRIMITIVE_MAP.put(Byte.TYPE.getName(), Byte.TYPE);
101        NAME_PRIMITIVE_MAP.put(Character.TYPE.getName(), Character.TYPE);
102        NAME_PRIMITIVE_MAP.put(Double.TYPE.getName(), Double.TYPE);
103        NAME_PRIMITIVE_MAP.put(Float.TYPE.getName(), Float.TYPE);
104        NAME_PRIMITIVE_MAP.put(Integer.TYPE.getName(), Integer.TYPE);
105        NAME_PRIMITIVE_MAP.put(Long.TYPE.getName(), Long.TYPE);
106        NAME_PRIMITIVE_MAP.put(Short.TYPE.getName(), Short.TYPE);
107        NAME_PRIMITIVE_MAP.put(Void.TYPE.getName(), Void.TYPE);
108    }
109
110    /**
111     * Maps primitive {@link Class}es to their corresponding wrapper {@link Class}.
112     */
113    private static final Map<Class<?>, Class<?>> PRIMITIVE_WRAPPER_MAP = new HashMap<>();
114
115    static {
116        PRIMITIVE_WRAPPER_MAP.put(Boolean.TYPE, Boolean.class);
117        PRIMITIVE_WRAPPER_MAP.put(Byte.TYPE, Byte.class);
118        PRIMITIVE_WRAPPER_MAP.put(Character.TYPE, Character.class);
119        PRIMITIVE_WRAPPER_MAP.put(Short.TYPE, Short.class);
120        PRIMITIVE_WRAPPER_MAP.put(Integer.TYPE, Integer.class);
121        PRIMITIVE_WRAPPER_MAP.put(Long.TYPE, Long.class);
122        PRIMITIVE_WRAPPER_MAP.put(Double.TYPE, Double.class);
123        PRIMITIVE_WRAPPER_MAP.put(Float.TYPE, Float.class);
124        PRIMITIVE_WRAPPER_MAP.put(Void.TYPE, Void.TYPE);
125    }
126
127    /**
128     * Maps wrapper {@link Class}es to their corresponding primitive types.
129     */
130    private static final Map<Class<?>, Class<?>> WRAPPER_PRIMITIVE_MAP = new HashMap<>();
131
132    static {
133        PRIMITIVE_WRAPPER_MAP.forEach((primitiveClass, wrapperClass) -> {
134            if (!primitiveClass.equals(wrapperClass)) {
135                WRAPPER_PRIMITIVE_MAP.put(wrapperClass, primitiveClass);
136            }
137        });
138    }
139
140    /**
141     * Maps a primitive class name to its corresponding abbreviation used in array class names.
142     */
143    private static final Map<String, String> ABBREVIATION_MAP;
144
145    /**
146     * Maps an abbreviation used in array class names to corresponding primitive class name.
147     */
148    private static final Map<String, String> REVERSE_ABBREVIATION_MAP;
149
150    /** Feed abbreviation maps. */
151    static {
152        final Map<String, String> map = new HashMap<>();
153        map.put(Integer.TYPE.getName(), "I");
154        map.put(Boolean.TYPE.getName(), "Z");
155        map.put(Float.TYPE.getName(), "F");
156        map.put(Long.TYPE.getName(), "J");
157        map.put(Short.TYPE.getName(), "S");
158        map.put(Byte.TYPE.getName(), "B");
159        map.put(Double.TYPE.getName(), "D");
160        map.put(Character.TYPE.getName(), "C");
161        ABBREVIATION_MAP = Collections.unmodifiableMap(map);
162        REVERSE_ABBREVIATION_MAP = Collections.unmodifiableMap(map.entrySet().stream().collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey)));
163    }
164
165    /**
166     * Gets the class comparator, comparing by class name.
167     *
168     * @return the class comparator.
169     * @since 3.13.0
170     */
171    public static Comparator<Class<?>> comparator() {
172        return COMPARATOR;
173    }
174
175    /**
176     * Given a {@link List} of {@link Class} objects, this method converts them into class names.
177     *
178     * <p>
179     * A new {@link List} is returned. {@code null} objects will be copied into the returned list as {@code null}.
180     * </p>
181     *
182     * @param classes the classes to change
183     * @return a {@link List} of class names corresponding to the Class objects, {@code null} if null input
184     * @throws ClassCastException if {@code classes} contains a non-{@link Class} entry
185     */
186    public static List<String> convertClassesToClassNames(final List<Class<?>> classes) {
187        return classes == null ? null : classes.stream().map(e -> getName(e, null)).collect(Collectors.toList());
188    }
189
190    /**
191     * Given a {@link List} of class names, this method converts them into classes.
192     *
193     * <p>
194     * A new {@link List} is returned. If the class name cannot be found, {@code null} is stored in the {@link List}. If the
195     * class name in the {@link List} is {@code null}, {@code null} is stored in the output {@link List}.
196     * </p>
197     *
198     * @param classNames the classNames to change
199     * @return a {@link List} of Class objects corresponding to the class names, {@code null} if null input
200     * @throws ClassCastException if classNames contains a non String entry
201     */
202    public static List<Class<?>> convertClassNamesToClasses(final List<String> classNames) {
203        if (classNames == null) {
204            return null;
205        }
206        final List<Class<?>> classes = new ArrayList<>(classNames.size());
207        classNames.forEach(className -> {
208            try {
209                classes.add(Class.forName(className));
210            } catch (final Exception ex) {
211                classes.add(null);
212            }
213        });
214        return classes;
215    }
216
217    /**
218     * Gets the abbreviated name of a {@link Class}.
219     *
220     * @param cls the class to get the abbreviated name for, may be {@code null}
221     * @param lengthHint the desired length of the abbreviated name
222     * @return the abbreviated name or an empty string
223     * @throws IllegalArgumentException if len &lt;= 0
224     * @see #getAbbreviatedName(String, int)
225     * @since 3.4
226     */
227    public static String getAbbreviatedName(final Class<?> cls, final int lengthHint) {
228        if (cls == null) {
229            return StringUtils.EMPTY;
230        }
231        return getAbbreviatedName(cls.getName(), lengthHint);
232    }
233
234    /**
235     * Gets the abbreviated class name from a {@link String}.
236     *
237     * <p>
238     * The string passed in is assumed to be a class name - it is not checked.
239     * </p>
240     *
241     * <p>
242     * The abbreviation algorithm will shorten the class name, usually without significant loss of meaning.
243     * </p>
244     *
245     * <p>
246     * The abbreviated class name will always include the complete package hierarchy. If enough space is available,
247     * rightmost sub-packages will be displayed in full length. The abbreviated package names will be shortened to a single
248     * character.
249     * </p>
250     * <p>
251     * Only package names are shortened, the class simple name remains untouched. (See examples.)
252     * </p>
253     * <p>
254     * The result will be longer than the desired length only if all the package names shortened to a single character plus
255     * the class simple name with the separating dots together are longer than the desired length. In other words, when the
256     * class name cannot be shortened to the desired length.
257     * </p>
258     * <p>
259     * If the class name can be shortened then the final length will be at most {@code lengthHint} characters.
260     * </p>
261     * <p>
262     * If the {@code lengthHint} is zero or negative then the method throws exception. If you want to achieve the shortest
263     * possible version then use {@code 1} as a {@code lengthHint}.
264     * </p>
265     *
266     * <table>
267     * <caption>Examples</caption>
268     * <tr>
269     * <td>className</td>
270     * <td>len</td>
271     * <td>return</td>
272     * </tr>
273     * <tr>
274     * <td>null</td>
275     * <td>1</td>
276     * <td>""</td>
277     * </tr>
278     * <tr>
279     * <td>"java.lang.String"</td>
280     * <td>5</td>
281     * <td>"j.l.String"</td>
282     * </tr>
283     * <tr>
284     * <td>"java.lang.String"</td>
285     * <td>15</td>
286     * <td>"j.lang.String"</td>
287     * </tr>
288     * <tr>
289     * <td>"java.lang.String"</td>
290     * <td>30</td>
291     * <td>"java.lang.String"</td>
292     * </tr>
293     * <tr>
294     * <td>"org.apache.commons.lang3.ClassUtils"</td>
295     * <td>18</td>
296     * <td>"o.a.c.l.ClassUtils"</td>
297     * </tr>
298     * </table>
299     *
300     * @param className the className to get the abbreviated name for, may be {@code null}
301     * @param lengthHint the desired length of the abbreviated name
302     * @return the abbreviated name or an empty string if the specified class name is {@code null} or empty string. The
303     *         abbreviated name may be longer than the desired length if it cannot be abbreviated to the desired length.
304     * @throws IllegalArgumentException if {@code len <= 0}
305     * @since 3.4
306     */
307    public static String getAbbreviatedName(final String className, final int lengthHint) {
308        if (lengthHint <= 0) {
309            throw new IllegalArgumentException("len must be > 0");
310        }
311        if (className == null) {
312            return StringUtils.EMPTY;
313        }
314        if (className.length() <= lengthHint) {
315            return className;
316        }
317        final char[] abbreviated = className.toCharArray();
318        int target = 0;
319        int source = 0;
320        while (source < abbreviated.length) {
321            // copy the next part
322            int runAheadTarget = target;
323            while (source < abbreviated.length && abbreviated[source] != '.') {
324                abbreviated[runAheadTarget++] = abbreviated[source++];
325            }
326
327            ++target;
328            if (useFull(runAheadTarget, source, abbreviated.length, lengthHint) || target > runAheadTarget) {
329                target = runAheadTarget;
330            }
331
332            // copy the '.' unless it was the last part
333            if (source < abbreviated.length) {
334                abbreviated[target++] = abbreviated[source++];
335            }
336        }
337        return new String(abbreviated, 0, target);
338    }
339
340    /**
341     * Gets a {@link List} of all interfaces implemented by the given class and its superclasses.
342     *
343     * <p>
344     * The order is determined by looking through each interface in turn as declared in the source file and following its
345     * hierarchy up. Then each superclass is considered in the same way. Later duplicates are ignored, so the order is
346     * maintained.
347     * </p>
348     *
349     * @param cls the class to look up, may be {@code null}
350     * @return the {@link List} of interfaces in order, {@code null} if null input
351     */
352    public static List<Class<?>> getAllInterfaces(final Class<?> cls) {
353        if (cls == null) {
354            return null;
355        }
356
357        final LinkedHashSet<Class<?>> interfacesFound = new LinkedHashSet<>();
358        getAllInterfaces(cls, interfacesFound);
359
360        return new ArrayList<>(interfacesFound);
361    }
362
363    /**
364     * Gets the interfaces for the specified class.
365     *
366     * @param cls the class to look up, may be {@code null}
367     * @param interfacesFound the {@link Set} of interfaces for the class
368     */
369    private static void getAllInterfaces(Class<?> cls, final HashSet<Class<?>> interfacesFound) {
370        while (cls != null) {
371            final Class<?>[] interfaces = cls.getInterfaces();
372
373            for (final Class<?> i : interfaces) {
374                if (interfacesFound.add(i)) {
375                    getAllInterfaces(i, interfacesFound);
376                }
377            }
378
379            cls = cls.getSuperclass();
380        }
381    }
382
383    /**
384     * Gets a {@link List} of superclasses for the given class.
385     *
386     * @param cls the class to look up, may be {@code null}
387     * @return the {@link List} of superclasses in order going up from this one {@code null} if null input
388     */
389    public static List<Class<?>> getAllSuperclasses(final Class<?> cls) {
390        if (cls == null) {
391            return null;
392        }
393        final List<Class<?>> classes = new ArrayList<>();
394        Class<?> superclass = cls.getSuperclass();
395        while (superclass != null) {
396            classes.add(superclass);
397            superclass = superclass.getSuperclass();
398        }
399        return classes;
400    }
401
402    /**
403     * Gets the canonical class name for a {@link Class}.
404     *
405     * @param cls the class for which to get the canonical class name; may be null
406     * @return the canonical name of the class, or the empty String
407     * @since 3.7
408     * @see Class#getCanonicalName()
409     */
410    public static String getCanonicalName(final Class<?> cls) {
411        return getCanonicalName(cls, StringUtils.EMPTY);
412    }
413
414    /**
415     * Gets the canonical name for a {@link Class}.
416     *
417     * @param cls the class for which to get the canonical class name; may be null
418     * @param valueIfNull the return value if null
419     * @return the canonical name of the class, or {@code valueIfNull}
420     * @since 3.7
421     * @see Class#getCanonicalName()
422     */
423    public static String getCanonicalName(final Class<?> cls, final String valueIfNull) {
424        if (cls == null) {
425            return valueIfNull;
426        }
427        final String canonicalName = cls.getCanonicalName();
428        return canonicalName == null ? valueIfNull : canonicalName;
429    }
430
431    /**
432     * Gets the canonical name for an {@link Object}.
433     *
434     * @param object the object for which to get the canonical class name; may be null
435     * @return the canonical name of the object, or the empty String
436     * @since 3.7
437     * @see Class#getCanonicalName()
438     */
439    public static String getCanonicalName(final Object object) {
440        return getCanonicalName(object, StringUtils.EMPTY);
441    }
442
443    /**
444     * Gets the canonical name for an {@link Object}.
445     *
446     * @param object the object for which to get the canonical class name; may be null
447     * @param valueIfNull the return value if null
448     * @return the canonical name of the object or {@code valueIfNull}
449     * @since 3.7
450     * @see Class#getCanonicalName()
451     */
452    public static String getCanonicalName(final Object object, final String valueIfNull) {
453        if (object == null) {
454            return valueIfNull;
455        }
456        final String canonicalName = object.getClass().getCanonicalName();
457        return canonicalName == null ? valueIfNull : canonicalName;
458    }
459
460    /**
461     * Converts a given name of class into canonical format. If name of class is not a name of array class it returns
462     * unchanged name.
463     *
464     * <p>
465     * The method does not change the {@code $} separators in case the class is inner class.
466     * </p>
467     *
468     * <p>
469     * Example:
470     * <ul>
471     * <li>{@code getCanonicalName("[I") = "int[]"}</li>
472     * <li>{@code getCanonicalName("[Ljava.lang.String;") = "java.lang.String[]"}</li>
473     * <li>{@code getCanonicalName("java.lang.String") = "java.lang.String"}</li>
474     * </ul>
475     * </p>
476     *
477     * @param className the name of class.
478     * @return canonical form of class name.
479     */
480    private static String getCanonicalName(final String name) {
481        String className = StringUtils.deleteWhitespace(name);
482        if (className == null) {
483            return null;
484        }
485        int dim = 0;
486        while (className.charAt(dim) == '[') {
487            dim++;
488            if (dim > MAX_DIMENSIONS) {
489                throw new IllegalArgumentException(String.format("Maximum array dimension %d exceeded", MAX_DIMENSIONS));
490            }
491        }
492        if (dim < 1) {
493            return className;
494        }
495        className = className.substring(dim);
496        if (className.startsWith("L")) {
497            className = className.substring(1, className.endsWith(";") ? className.length() - 1 : className.length());
498        } else if (!className.isEmpty()) {
499            className = REVERSE_ABBREVIATION_MAP.get(className.substring(0, 1));
500        }
501        final StringBuilder canonicalClassNameBuffer = new StringBuilder(className.length() + dim * 2);
502        canonicalClassNameBuffer.append(className);
503        for (int i = 0; i < dim; i++) {
504            canonicalClassNameBuffer.append("[]");
505        }
506        return canonicalClassNameBuffer.toString();
507    }
508
509    /**
510     * Gets the (initialized) class represented by {@code className} using the {@code classLoader}. This implementation
511     * supports the syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
512     * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
513     *
514     * @param classLoader the class loader to use to load the class
515     * @param className the class name
516     * @return the class represented by {@code className} using the {@code classLoader}
517     * @throws NullPointerException if the className is null
518     * @throws ClassNotFoundException if the class is not found
519     */
520    public static Class<?> getClass(final ClassLoader classLoader, final String className) throws ClassNotFoundException {
521        return getClass(classLoader, className, true);
522    }
523
524    /**
525     * Gets the class represented by {@code className} using the {@code classLoader}. This implementation supports the
526     * syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}", and
527     * "{@code [Ljava.util.Map$Entry;}".
528     *
529     * @param classLoader the class loader to use to load the class
530     * @param className the class name
531     * @param initialize whether the class must be initialized
532     * @return the class represented by {@code className} using the {@code classLoader}
533     * @throws NullPointerException if the className is null
534     * @throws ClassNotFoundException if the class is not found
535     */
536    public static Class<?> getClass(final ClassLoader classLoader, final String className, final boolean initialize) throws ClassNotFoundException {
537        // This method was re-written to avoid recursion and stack overflows found by fuzz testing.
538        String next = className;
539        int lastDotIndex = -1;
540        do {
541            try {
542                final Class<?> clazz = getPrimitiveClass(next);
543                return clazz != null ? clazz : Class.forName(toCanonicalName(next), initialize, classLoader);
544            } catch (final ClassNotFoundException ex) {
545                lastDotIndex = next.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
546                if (lastDotIndex != -1) {
547                    next = next.substring(0, lastDotIndex) + INNER_CLASS_SEPARATOR_CHAR + next.substring(lastDotIndex + 1);
548                }
549            }
550        } while (lastDotIndex != -1);
551        throw new ClassNotFoundException(next);
552    }
553
554    /**
555     * Gets the (initialized) class represented by {@code className} using the current thread's context class loader.
556     * This implementation supports the syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
557     * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
558     *
559     * @param className the class name
560     * @return the class represented by {@code className} using the current thread's context class loader
561     * @throws NullPointerException if the className is null
562     * @throws ClassNotFoundException if the class is not found
563     */
564    public static Class<?> getClass(final String className) throws ClassNotFoundException {
565        return getClass(className, true);
566    }
567
568    /**
569     * Gets the class represented by {@code className} using the current thread's context class loader. This
570     * implementation supports the syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
571     * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
572     *
573     * @param className the class name
574     * @param initialize whether the class must be initialized
575     * @return the class represented by {@code className} using the current thread's context class loader
576     * @throws NullPointerException if the className is null
577     * @throws ClassNotFoundException if the class is not found
578     */
579    public static Class<?> getClass(final String className, final boolean initialize) throws ClassNotFoundException {
580        final ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
581        final ClassLoader loader = contextCL == null ? ClassUtils.class.getClassLoader() : contextCL;
582        return getClass(loader, className, initialize);
583    }
584
585    /**
586     * Delegates to {@link Class#getComponentType()} using generics.
587     *
588     * @param <T> The array class type.
589     * @param cls A class or null.
590     * @return The array component type or null.
591     * @see Class#getComponentType()
592     * @since 3.13.0
593     */
594    @SuppressWarnings("unchecked")
595    public static <T> Class<T> getComponentType(final Class<T[]> cls) {
596        return cls == null ? null : (Class<T>) cls.getComponentType();
597    }
598
599    /**
600     * Null-safe version of {@code cls.getName()}
601     *
602     * @param cls the class for which to get the class name; may be null
603     * @return the class name or the empty string in case the argument is {@code null}
604     * @since 3.7
605     * @see Class#getSimpleName()
606     */
607    public static String getName(final Class<?> cls) {
608        return getName(cls, StringUtils.EMPTY);
609    }
610
611    /**
612     * Null-safe version of {@code cls.getName()}
613     *
614     * @param cls the class for which to get the class name; may be null
615     * @param valueIfNull the return value if the argument {@code cls} is {@code null}
616     * @return the class name or {@code valueIfNull}
617     * @since 3.7
618     * @see Class#getName()
619     */
620    public static String getName(final Class<?> cls, final String valueIfNull) {
621        return cls == null ? valueIfNull : cls.getName();
622    }
623
624    /**
625     * Null-safe version of {@code object.getClass().getName()}
626     *
627     * @param object the object for which to get the class name; may be null
628     * @return the class name or the empty String
629     * @since 3.7
630     * @see Class#getSimpleName()
631     */
632    public static String getName(final Object object) {
633        return getName(object, StringUtils.EMPTY);
634    }
635
636    /**
637     * Null-safe version of {@code object.getClass().getSimpleName()}
638     *
639     * @param object the object for which to get the class name; may be null
640     * @param valueIfNull the value to return if {@code object} is {@code null}
641     * @return the class name or {@code valueIfNull}
642     * @since 3.0
643     * @see Class#getName()
644     */
645    public static String getName(final Object object, final String valueIfNull) {
646        return object == null ? valueIfNull : object.getClass().getName();
647    }
648
649    /**
650     * Gets the package name from the canonical name of a {@link Class}.
651     *
652     * @param cls the class to get the package name for, may be {@code null}.
653     * @return the package name or an empty string
654     * @since 2.4
655     */
656    public static String getPackageCanonicalName(final Class<?> cls) {
657        if (cls == null) {
658            return StringUtils.EMPTY;
659        }
660        return getPackageCanonicalName(cls.getName());
661    }
662
663    /**
664     * Gets the package name from the class name of an {@link Object}.
665     *
666     * @param object the class to get the package name for, may be null
667     * @param valueIfNull the value to return if null
668     * @return the package name of the object, or the null value
669     * @since 2.4
670     */
671    public static String getPackageCanonicalName(final Object object, final String valueIfNull) {
672        if (object == null) {
673            return valueIfNull;
674        }
675        return getPackageCanonicalName(object.getClass().getName());
676    }
677
678    /**
679     * Gets the package name from the class name.
680     *
681     * <p>
682     * The string passed in is assumed to be a class name - it is not checked.
683     * </p>
684     * <p>
685     * If the class is in the default package, return an empty string.
686     * </p>
687     *
688     * @param name the name to get the package name for, may be {@code null}
689     * @return the package name or an empty string
690     * @since 2.4
691     */
692    public static String getPackageCanonicalName(final String name) {
693        return getPackageName(getCanonicalName(name));
694    }
695
696    /**
697     * Gets the package name of a {@link Class}.
698     *
699     * @param cls the class to get the package name for, may be {@code null}.
700     * @return the package name or an empty string
701     */
702    public static String getPackageName(final Class<?> cls) {
703        if (cls == null) {
704            return StringUtils.EMPTY;
705        }
706        return getPackageName(cls.getName());
707    }
708
709    /**
710     * Gets the package name of an {@link Object}.
711     *
712     * @param object the class to get the package name for, may be null
713     * @param valueIfNull the value to return if null
714     * @return the package name of the object, or the null value
715     */
716    public static String getPackageName(final Object object, final String valueIfNull) {
717        if (object == null) {
718            return valueIfNull;
719        }
720        return getPackageName(object.getClass());
721    }
722
723    /**
724     * Gets the package name from a {@link String}.
725     *
726     * <p>
727     * The string passed in is assumed to be a class name - it is not checked.
728     * </p>
729     * <p>
730     * If the class is unpackaged, return an empty string.
731     * </p>
732     *
733     * @param className the className to get the package name for, may be {@code null}
734     * @return the package name or an empty string
735     */
736    public static String getPackageName(String className) {
737        if (StringUtils.isEmpty(className)) {
738            return StringUtils.EMPTY;
739        }
740
741        // Strip array encoding
742        while (className.charAt(0) == '[') {
743            className = className.substring(1);
744        }
745        // Strip Object type encoding
746        if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
747            className = className.substring(1);
748        }
749
750        final int i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
751        if (i == -1) {
752            return StringUtils.EMPTY;
753        }
754        return className.substring(0, i);
755    }
756
757    /**
758     * Gets the primitive class for the given class name, for example "byte".
759     *
760     * @param className the primitive class for the given class name.
761     * @return the primitive class.
762     */
763    static Class<?> getPrimitiveClass(final String className) {
764        return NAME_PRIMITIVE_MAP.get(className);
765    }
766
767    /**
768     * Gets the desired Method much like {@code Class.getMethod}, however it ensures that the returned Method is from a
769     * public class or interface and not from an anonymous inner class. This means that the Method is invokable and doesn't
770     * fall foul of Java bug <a href="https://bugs.java.com/bugdatabase/view_bug.do?bug_id=4071957">4071957</a>).
771     *
772     * <pre>
773     *  {@code Set set = Collections.unmodifiableSet(...);
774     *  Method method = ClassUtils.getPublicMethod(set.getClass(), "isEmpty",  new Class[0]);
775     *  Object result = method.invoke(set, new Object[]);}
776     * </pre>
777     *
778     * @param cls the class to check, not null
779     * @param methodName the name of the method
780     * @param parameterTypes the list of parameters
781     * @return the method
782     * @throws NullPointerException if the class is null
783     * @throws SecurityException if a security violation occurred
784     * @throws NoSuchMethodException if the method is not found in the given class or if the method doesn't conform with the
785     *         requirements
786     */
787    public static Method getPublicMethod(final Class<?> cls, final String methodName, final Class<?>... parameterTypes) throws NoSuchMethodException {
788
789        final Method declaredMethod = cls.getMethod(methodName, parameterTypes);
790        if (isPublic(declaredMethod.getDeclaringClass())) {
791            return declaredMethod;
792        }
793
794        final List<Class<?>> candidateClasses = new ArrayList<>(getAllInterfaces(cls));
795        candidateClasses.addAll(getAllSuperclasses(cls));
796
797        for (final Class<?> candidateClass : candidateClasses) {
798            if (!isPublic(candidateClass)) {
799                continue;
800            }
801            final Method candidateMethod;
802            try {
803                candidateMethod = candidateClass.getMethod(methodName, parameterTypes);
804            } catch (final NoSuchMethodException ex) {
805                continue;
806            }
807            if (Modifier.isPublic(candidateMethod.getDeclaringClass().getModifiers())) {
808                return candidateMethod;
809            }
810        }
811
812        throw new NoSuchMethodException("Can't find a public method for " + methodName + " " + ArrayUtils.toString(parameterTypes));
813    }
814
815    /**
816     * Gets the canonical name minus the package name from a {@link Class}.
817     *
818     * @param cls the class for which to get the short canonical class name; may be null
819     * @return the canonical name without the package name or an empty string
820     * @since 2.4
821     * @see Class#getCanonicalName()
822     */
823    public static String getShortCanonicalName(final Class<?> cls) {
824        return cls == null ? StringUtils.EMPTY : getShortCanonicalName(cls.getCanonicalName());
825    }
826
827    /**
828     * Gets the canonical name minus the package name for an {@link Object}.
829     *
830     * @param object the class to get the short name for, may be null
831     * @param valueIfNull the value to return if null
832     * @return the canonical name of the object without the package name, or the null value
833     * @since 2.4
834     * @see Class#getCanonicalName()
835     */
836    public static String getShortCanonicalName(final Object object, final String valueIfNull) {
837        return object == null ? valueIfNull : getShortCanonicalName(object.getClass().getCanonicalName());
838    }
839
840    /**
841     * Gets the canonical name minus the package name from a String.
842     *
843     * <p>
844     * The string passed in is assumed to be a class name - it is not checked.
845     * </p>
846     *
847     * <p>
848     * Note that this method is mainly designed to handle the arrays and primitives properly. If the class is an inner class
849     * then the result value will not contain the outer classes. This way the behavior of this method is different from
850     * {@link #getShortClassName(String)}. The argument in that case is class name and not canonical name and the return
851     * value retains the outer classes.
852     * </p>
853     *
854     * <p>
855     * Note that there is no way to reliably identify the part of the string representing the package hierarchy and the part
856     * that is the outer class or classes in case of an inner class. Trying to find the class would require reflective call
857     * and the class itself may not even be on the class path. Relying on the fact that class names start with capital
858     * letter and packages with lower case is heuristic.
859     * </p>
860     *
861     * <p>
862     * It is recommended to use {@link #getShortClassName(String)} for cases when the class is an inner class and use this
863     * method for cases it is designed for.
864     * </p>
865     *
866     * <table>
867     * <caption>Examples</caption>
868     * <tr>
869     * <td>return value</td>
870     * <td>input</td>
871     * </tr>
872     * <tr>
873     * <td>{@code ""}</td>
874     * <td>{@code (String) null}</td>
875     * </tr>
876     * <tr>
877     * <td>{@code "Map.Entry"}</td>
878     * <td>{@code java.util.Map.Entry.class.getName()}</td>
879     * </tr>
880     * <tr>
881     * <td>{@code "Entry"}</td>
882     * <td>{@code java.util.Map.Entry.class.getCanonicalName()}</td>
883     * </tr>
884     * <tr>
885     * <td>{@code "ClassUtils"}</td>
886     * <td>{@code "org.apache.commons.lang3.ClassUtils"}</td>
887     * </tr>
888     * <tr>
889     * <td>{@code "ClassUtils[]"}</td>
890     * <td>{@code "[Lorg.apache.commons.lang3.ClassUtils;"}</td>
891     * </tr>
892     * <tr>
893     * <td>{@code "ClassUtils[][]"}</td>
894     * <td>{@code "[[Lorg.apache.commons.lang3.ClassUtils;"}</td>
895     * </tr>
896     * <tr>
897     * <td>{@code "ClassUtils[]"}</td>
898     * <td>{@code "org.apache.commons.lang3.ClassUtils[]"}</td>
899     * </tr>
900     * <tr>
901     * <td>{@code "ClassUtils[][]"}</td>
902     * <td>{@code "org.apache.commons.lang3.ClassUtils[][]"}</td>
903     * </tr>
904     * <tr>
905     * <td>{@code "int[]"}</td>
906     * <td>{@code "[I"}</td>
907     * </tr>
908     * <tr>
909     * <td>{@code "int[]"}</td>
910     * <td>{@code int[].class.getCanonicalName()}</td>
911     * </tr>
912     * <tr>
913     * <td>{@code "int[]"}</td>
914     * <td>{@code int[].class.getName()}</td>
915     * </tr>
916     * <tr>
917     * <td>{@code "int[][]"}</td>
918     * <td>{@code "[[I"}</td>
919     * </tr>
920     * <tr>
921     * <td>{@code "int[]"}</td>
922     * <td>{@code "int[]"}</td>
923     * </tr>
924     * <tr>
925     * <td>{@code "int[][]"}</td>
926     * <td>{@code "int[][]"}</td>
927     * </tr>
928     * </table>
929     *
930     * @param canonicalName the class name to get the short name for
931     * @return the canonical name of the class without the package name or an empty string
932     * @since 2.4
933     */
934    public static String getShortCanonicalName(final String canonicalName) {
935        return getShortClassName(getCanonicalName(canonicalName));
936    }
937
938    /**
939     * Gets the class name minus the package name from a {@link Class}.
940     *
941     * <p>
942     * This method simply gets the name using {@code Class.getName()} and then calls {@link #getShortClassName(String)}. See
943     * relevant notes there.
944     * </p>
945     *
946     * @param cls the class to get the short name for.
947     * @return the class name without the package name or an empty string. If the class is an inner class then the returned
948     *         value will contain the outer class or classes separated with {@code .} (dot) character.
949     */
950    public static String getShortClassName(final Class<?> cls) {
951        if (cls == null) {
952            return StringUtils.EMPTY;
953        }
954        return getShortClassName(cls.getName());
955    }
956
957    /**
958     * Gets the class name of the {@code object} without the package name or names.
959     *
960     * <p>
961     * The method looks up the class of the object and then converts the name of the class invoking
962     * {@link #getShortClassName(Class)} (see relevant notes there).
963     * </p>
964     *
965     * @param object the class to get the short name for, may be {@code null}
966     * @param valueIfNull the value to return if the object is {@code null}
967     * @return the class name of the object without the package name, or {@code valueIfNull} if the argument {@code object}
968     *         is {@code null}
969     */
970    public static String getShortClassName(final Object object, final String valueIfNull) {
971        if (object == null) {
972            return valueIfNull;
973        }
974        return getShortClassName(object.getClass());
975    }
976
977    /**
978     * Gets the class name minus the package name from a String.
979     *
980     * <p>
981     * 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
982     * JDK method {@code Class.getName()} returns it, and not the usual way as we write it, for example in import
983     * statements, or as it is formatted by {@code Class.getCanonicalName()}.
984     * </p>
985     *
986     * <p>
987     * The difference is is significant only in case of classes that are inner classes of some other classes. In this case
988     * the separator between the outer and inner class (possibly on multiple hierarchy level) has to be {@code $} (dollar
989     * sign) and not {@code .} (dot), as it is returned by {@code Class.getName()}
990     * </p>
991     *
992     * <p>
993     * Note that this method is called from the {@link #getShortClassName(Class)} method using the string returned by
994     * {@code Class.getName()}.
995     * </p>
996     *
997     * <p>
998     * Note that this method differs from {@link #getSimpleName(Class)} in that this will return, for example
999     * {@code "Map.Entry"} whilst the {@link Class} variant will simply return {@code "Entry"}. In this example
1000     * the argument {@code className} is the string {@code java.util.Map$Entry} (note the {@code $} sign.
1001     * </p>
1002     *
1003     * @param className the className to get the short name for. It has to be formatted as returned by
1004     *        {@code Class.getName()} and not {@code Class.getCanonicalName()}
1005     * @return the class name of the class without the package name or an empty string. If the class is an inner class then
1006     *         value contains the outer class or classes and the separator is replaced to be {@code .} (dot) character.
1007     */
1008    public static String getShortClassName(String className) {
1009        if (StringUtils.isEmpty(className)) {
1010            return StringUtils.EMPTY;
1011        }
1012
1013        final StringBuilder arrayPrefix = new StringBuilder();
1014
1015        // Handle array encoding
1016        if (className.startsWith("[")) {
1017            while (className.charAt(0) == '[') {
1018                className = className.substring(1);
1019                arrayPrefix.append("[]");
1020            }
1021            // Strip Object type encoding
1022            if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
1023                className = className.substring(1, className.length() - 1);
1024            }
1025
1026            if (REVERSE_ABBREVIATION_MAP.containsKey(className)) {
1027                className = REVERSE_ABBREVIATION_MAP.get(className);
1028            }
1029        }
1030
1031        final int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
1032        final int innerIdx = className.indexOf(INNER_CLASS_SEPARATOR_CHAR, lastDotIdx == -1 ? 0 : lastDotIdx + 1);
1033        String out = className.substring(lastDotIdx + 1);
1034        if (innerIdx != -1) {
1035            out = out.replace(INNER_CLASS_SEPARATOR_CHAR, PACKAGE_SEPARATOR_CHAR);
1036        }
1037        return out + arrayPrefix;
1038    }
1039
1040    /**
1041     * Null-safe version of {@code cls.getSimpleName()}
1042     *
1043     * @param cls the class for which to get the simple name; may be null
1044     * @return the simple class name or the empty string in case the argument is {@code null}
1045     * @since 3.0
1046     * @see Class#getSimpleName()
1047     */
1048    public static String getSimpleName(final Class<?> cls) {
1049        return getSimpleName(cls, StringUtils.EMPTY);
1050    }
1051
1052    /**
1053     * Null-safe version of {@code cls.getSimpleName()}
1054     *
1055     * @param cls the class for which to get the simple name; may be null
1056     * @param valueIfNull the value to return if null
1057     * @return the simple class name or {@code valueIfNull} if the argument {@code cls} is {@code null}
1058     * @since 3.0
1059     * @see Class#getSimpleName()
1060     */
1061    public static String getSimpleName(final Class<?> cls, final String valueIfNull) {
1062        return cls == null ? valueIfNull : cls.getSimpleName();
1063    }
1064
1065    /**
1066     * Null-safe version of {@code object.getClass().getSimpleName()}
1067     *
1068     * <p>
1069     * It is to note that this method is overloaded and in case the argument {@code object} is a {@link Class} object then
1070     * the {@link #getSimpleName(Class)} will be invoked. If this is a significant possibility then the caller should check
1071     * this case and call {@code
1072     * getSimpleName(Class.class)} or just simply use the string literal {@code "Class"}, which is the result of the method
1073     * in that case.
1074     * </p>
1075     *
1076     * @param object the object for which to get the simple class name; may be null
1077     * @return the simple class name or the empty string in case the argument is {@code null}
1078     * @since 3.7
1079     * @see Class#getSimpleName()
1080     */
1081    public static String getSimpleName(final Object object) {
1082        return getSimpleName(object, StringUtils.EMPTY);
1083    }
1084
1085    /**
1086     * Null-safe version of {@code object.getClass().getSimpleName()}
1087     *
1088     * @param object the object for which to get the simple class name; may be null
1089     * @param valueIfNull the value to return if {@code object} is {@code null}
1090     * @return the simple class name or {@code valueIfNull} if the argument {@code object} is {@code null}
1091     * @since 3.0
1092     * @see Class#getSimpleName()
1093     */
1094    public static String getSimpleName(final Object object, final String valueIfNull) {
1095        return object == null ? valueIfNull : object.getClass().getSimpleName();
1096    }
1097
1098    /**
1099     * Gets an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order,
1100     * excluding interfaces.
1101     *
1102     * @param type the type to get the class hierarchy from
1103     * @return Iterable an Iterable over the class hierarchy of the given class
1104     * @since 3.2
1105     */
1106    public static Iterable<Class<?>> hierarchy(final Class<?> type) {
1107        return hierarchy(type, Interfaces.EXCLUDE);
1108    }
1109
1110    /**
1111     * Gets an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order.
1112     *
1113     * @param type the type to get the class hierarchy from
1114     * @param interfacesBehavior switch indicating whether to include or exclude interfaces
1115     * @return Iterable an Iterable over the class hierarchy of the given class
1116     * @since 3.2
1117     */
1118    public static Iterable<Class<?>> hierarchy(final Class<?> type, final Interfaces interfacesBehavior) {
1119        final Iterable<Class<?>> classes = () -> {
1120            final AtomicReference<Class<?>> next = new AtomicReference<>(type);
1121            return new Iterator<Class<?>>() {
1122
1123                @Override
1124                public boolean hasNext() {
1125                    return next.get() != null;
1126                }
1127
1128                @Override
1129                public Class<?> next() {
1130                    return next.getAndUpdate(Class::getSuperclass);
1131                }
1132
1133                @Override
1134                public void remove() {
1135                    throw new UnsupportedOperationException();
1136                }
1137
1138            };
1139        };
1140        if (interfacesBehavior != Interfaces.INCLUDE) {
1141            return classes;
1142        }
1143        return () -> {
1144            final Set<Class<?>> seenInterfaces = new HashSet<>();
1145            final Iterator<Class<?>> wrapped = classes.iterator();
1146
1147            return new Iterator<Class<?>>() {
1148                Iterator<Class<?>> interfaces = Collections.emptyIterator();
1149
1150                @Override
1151                public boolean hasNext() {
1152                    return interfaces.hasNext() || wrapped.hasNext();
1153                }
1154
1155                @Override
1156                public Class<?> next() {
1157                    if (interfaces.hasNext()) {
1158                        final Class<?> nextInterface = interfaces.next();
1159                        seenInterfaces.add(nextInterface);
1160                        return nextInterface;
1161                    }
1162                    final Class<?> nextSuperclass = wrapped.next();
1163                    final Set<Class<?>> currentInterfaces = new LinkedHashSet<>();
1164                    walkInterfaces(currentInterfaces, nextSuperclass);
1165                    interfaces = currentInterfaces.iterator();
1166                    return nextSuperclass;
1167                }
1168
1169                @Override
1170                public void remove() {
1171                    throw new UnsupportedOperationException();
1172                }
1173
1174                private void walkInterfaces(final Set<Class<?>> addTo, final Class<?> c) {
1175                    for (final Class<?> iface : c.getInterfaces()) {
1176                        if (!seenInterfaces.contains(iface)) {
1177                            addTo.add(iface);
1178                        }
1179                        walkInterfaces(addTo, iface);
1180                    }
1181                }
1182
1183            };
1184        };
1185    }
1186
1187    /**
1188     * Checks if one {@link Class} can be assigned to a variable of another {@link Class}.
1189     *
1190     * <p>
1191     * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1192     * primitive classes and {@code null}s.
1193     * </p>
1194     *
1195     * <p>
1196     * Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result
1197     * for these cases.
1198     * </p>
1199     *
1200     * <p>
1201     * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1202     * and the toClass is non-primitive.
1203     * </p>
1204     *
1205     * <p>
1206     * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1207     * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1208     * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1209     * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1210     * </p>
1211     *
1212     * <p>
1213     * <strong>Since Lang 3.0,</strong> this method will default behavior for calculating assignability between primitive
1214     * and wrapper types <em>corresponding to the running Java version</em>; i.e. autoboxing will be the default behavior in
1215     * VMs running Java versions &gt; 1.5.
1216     * </p>
1217     *
1218     * @param cls the Class to check, may be null
1219     * @param toClass the Class to try to assign into, returns false if null
1220     * @return {@code true} if assignment possible
1221     */
1222    public static boolean isAssignable(final Class<?> cls, final Class<?> toClass) {
1223        return isAssignable(cls, toClass, true);
1224    }
1225
1226    /**
1227     * Checks if one {@link Class} can be assigned to a variable of another {@link Class}.
1228     *
1229     * <p>
1230     * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1231     * primitive classes and {@code null}s.
1232     * </p>
1233     *
1234     * <p>
1235     * Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result
1236     * for these cases.
1237     * </p>
1238     *
1239     * <p>
1240     * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1241     * and the toClass is non-primitive.
1242     * </p>
1243     *
1244     * <p>
1245     * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1246     * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1247     * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1248     * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1249     * </p>
1250     *
1251     * @param cls the Class to check, may be null
1252     * @param toClass the Class to try to assign into, returns false if null
1253     * @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers
1254     * @return {@code true} if assignment possible
1255     */
1256    public static boolean isAssignable(Class<?> cls, final Class<?> toClass, final boolean autoboxing) {
1257        if (toClass == null) {
1258            return false;
1259        }
1260        // have to check for null, as isAssignableFrom doesn't
1261        if (cls == null) {
1262            return !toClass.isPrimitive();
1263        }
1264        // autoboxing:
1265        if (autoboxing) {
1266            if (cls.isPrimitive() && !toClass.isPrimitive()) {
1267                cls = primitiveToWrapper(cls);
1268                if (cls == null) {
1269                    return false;
1270                }
1271            }
1272            if (toClass.isPrimitive() && !cls.isPrimitive()) {
1273                cls = wrapperToPrimitive(cls);
1274                if (cls == null) {
1275                    return false;
1276                }
1277            }
1278        }
1279        if (cls.equals(toClass)) {
1280            return true;
1281        }
1282        if (cls.isPrimitive()) {
1283            if (!toClass.isPrimitive()) {
1284                return false;
1285            }
1286            if (Integer.TYPE.equals(cls)) {
1287                return Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
1288            }
1289            if (Long.TYPE.equals(cls)) {
1290                return Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
1291            }
1292            if (Boolean.TYPE.equals(cls)) {
1293                return false;
1294            }
1295            if (Double.TYPE.equals(cls)) {
1296                return false;
1297            }
1298            if (Float.TYPE.equals(cls)) {
1299                return Double.TYPE.equals(toClass);
1300            }
1301            if (Character.TYPE.equals(cls)  || Short.TYPE.equals(cls)) {
1302                return Integer.TYPE.equals(toClass) || Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
1303            }
1304            if (Byte.TYPE.equals(cls)) {
1305                return Short.TYPE.equals(toClass) || Integer.TYPE.equals(toClass) || Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass)
1306                    || Double.TYPE.equals(toClass);
1307            }
1308            // should never get here
1309            return false;
1310        }
1311        return toClass.isAssignableFrom(cls);
1312    }
1313
1314    /**
1315     * Checks if an array of Classes can be assigned to another array of Classes.
1316     *
1317     * <p>
1318     * This method calls {@link #isAssignable(Class, Class) isAssignable} for each Class pair in the input arrays. It can be
1319     * used to check if a set of arguments (the first parameter) are suitably compatible with a set of method parameter
1320     * types (the second parameter).
1321     * </p>
1322     *
1323     * <p>
1324     * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1325     * primitive classes and {@code null}s.
1326     * </p>
1327     *
1328     * <p>
1329     * Primitive widenings allow an int to be assigned to a {@code long}, {@code float} or {@code double}. This method
1330     * returns the correct result for these cases.
1331     * </p>
1332     *
1333     * <p>
1334     * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1335     * and the toClass is non-primitive.
1336     * </p>
1337     *
1338     * <p>
1339     * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1340     * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1341     * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1342     * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1343     * </p>
1344     *
1345     * <p>
1346     * <strong>Since Lang 3.0,</strong> this method will default behavior for calculating assignability between primitive
1347     * and wrapper types <em>corresponding to the running Java version</em>; i.e. autoboxing will be the default behavior in
1348     * VMs running Java versions &gt; 1.5.
1349     * </p>
1350     *
1351     * @param classArray the array of Classes to check, may be {@code null}
1352     * @param toClassArray the array of Classes to try to assign into, may be {@code null}
1353     * @return {@code true} if assignment possible
1354     */
1355    public static boolean isAssignable(final Class<?>[] classArray, final Class<?>... toClassArray) {
1356        return isAssignable(classArray, toClassArray, true);
1357    }
1358
1359    /**
1360     * Checks if an array of Classes can be assigned to another array of Classes.
1361     *
1362     * <p>
1363     * This method calls {@link #isAssignable(Class, Class) isAssignable} for each Class pair in the input arrays. It can be
1364     * used to check if a set of arguments (the first parameter) are suitably compatible with a set of method parameter
1365     * types (the second parameter).
1366     * </p>
1367     *
1368     * <p>
1369     * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1370     * primitive classes and {@code null}s.
1371     * </p>
1372     *
1373     * <p>
1374     * Primitive widenings allow an int to be assigned to a {@code long}, {@code float} or {@code double}. This method
1375     * returns the correct result for these cases.
1376     * </p>
1377     *
1378     * <p>
1379     * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1380     * and the toClass is non-primitive.
1381     * </p>
1382     *
1383     * <p>
1384     * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1385     * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1386     * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1387     * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1388     * </p>
1389     *
1390     * @param classArray the array of Classes to check, may be {@code null}
1391     * @param toClassArray the array of Classes to try to assign into, may be {@code null}
1392     * @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers
1393     * @return {@code true} if assignment possible
1394     */
1395    public static boolean isAssignable(Class<?>[] classArray, Class<?>[] toClassArray, final boolean autoboxing) {
1396        if (!ArrayUtils.isSameLength(classArray, toClassArray)) {
1397            return false;
1398        }
1399        classArray = ArrayUtils.nullToEmpty(classArray);
1400        toClassArray = ArrayUtils.nullToEmpty(toClassArray);
1401        for (int i = 0; i < classArray.length; i++) {
1402            if (!isAssignable(classArray[i], toClassArray[i], autoboxing)) {
1403                return false;
1404            }
1405        }
1406        return true;
1407    }
1408
1409    /**
1410     * Is the specified class an inner class or static nested class.
1411     *
1412     * @param cls the class to check, may be null
1413     * @return {@code true} if the class is an inner or static nested class, false if not or {@code null}
1414     */
1415    public static boolean isInnerClass(final Class<?> cls) {
1416        return cls != null && cls.getEnclosingClass() != null;
1417    }
1418
1419    /**
1420     * Returns whether the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte},
1421     * {@link Character}, {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1422     *
1423     * @param type The class to query or null.
1424     * @return true if the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte},
1425     *         {@link Character}, {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1426     * @since 3.1
1427     */
1428    public static boolean isPrimitiveOrWrapper(final Class<?> type) {
1429        if (type == null) {
1430            return false;
1431        }
1432        return type.isPrimitive() || isPrimitiveWrapper(type);
1433    }
1434    /**
1435     * Tests whether the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
1436     * {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1437     *
1438     * @param type The class to query or null.
1439     * @return true if the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
1440     *         {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1441     * @since 3.1
1442     */
1443    public static boolean isPrimitiveWrapper(final Class<?> type) {
1444        return WRAPPER_PRIMITIVE_MAP.containsKey(type);
1445    }
1446
1447    /**
1448     * Tests whether a {@link Class} is public.
1449     * @param cls Class to test.
1450     * @return {@code true} if {@code cls} is public.
1451     * @since 3.13.0
1452     */
1453    public static boolean isPublic(final Class<?> cls) {
1454        return Modifier.isPublic(cls.getModifiers());
1455    }
1456
1457    /**
1458     * Converts the specified array of primitive Class objects to an array of its corresponding wrapper Class objects.
1459     *
1460     * @param classes the class array to convert, may be null or empty
1461     * @return an array which contains for each given class, the wrapper class or the original class if class is not a
1462     *         primitive. {@code null} if null input. Empty array if an empty array passed in.
1463     * @since 2.1
1464     */
1465    public static Class<?>[] primitivesToWrappers(final Class<?>... classes) {
1466        if (classes == null) {
1467            return null;
1468        }
1469
1470        if (classes.length == 0) {
1471            return classes;
1472        }
1473
1474        final Class<?>[] convertedClasses = new Class[classes.length];
1475        Arrays.setAll(convertedClasses, i -> primitiveToWrapper(classes[i]));
1476        return convertedClasses;
1477    }
1478
1479    /**
1480     * Converts the specified primitive Class object to its corresponding wrapper Class object.
1481     *
1482     * <p>
1483     * NOTE: From v2.2, this method handles {@code Void.TYPE}, returning {@code Void.TYPE}.
1484     * </p>
1485     *
1486     * @param cls the class to convert, may be null
1487     * @return the wrapper class for {@code cls} or {@code cls} if {@code cls} is not a primitive. {@code null} if null
1488     *         input.
1489     * @since 2.1
1490     */
1491    public static Class<?> primitiveToWrapper(final Class<?> cls) {
1492        Class<?> convertedClass = cls;
1493        if (cls != null && cls.isPrimitive()) {
1494            convertedClass = PRIMITIVE_WRAPPER_MAP.get(cls);
1495        }
1496        return convertedClass;
1497    }
1498
1499    /**
1500     * Converts a class name to a JLS style class name.
1501     *
1502     * @param className the class name
1503     * @return the converted name
1504     * @throws NullPointerException if the className is null
1505     */
1506    private static String toCanonicalName(final String className) {
1507        String canonicalName = StringUtils.deleteWhitespace(className);
1508        Objects.requireNonNull(canonicalName, "className");
1509        final String arrayMarker = "[]";
1510        if (canonicalName.endsWith(arrayMarker)) {
1511            final StringBuilder classNameBuffer = new StringBuilder();
1512            while (canonicalName.endsWith(arrayMarker)) {
1513                canonicalName = canonicalName.substring(0, canonicalName.length() - 2);
1514                classNameBuffer.append("[");
1515            }
1516            final String abbreviation = ABBREVIATION_MAP.get(canonicalName);
1517            if (abbreviation != null) {
1518                classNameBuffer.append(abbreviation);
1519            } else {
1520                classNameBuffer.append("L").append(canonicalName).append(";");
1521            }
1522            canonicalName = classNameBuffer.toString();
1523        }
1524        return canonicalName;
1525    }
1526
1527    /**
1528     * Converts an array of {@link Object} in to an array of {@link Class} objects. If any of these objects is null, a null
1529     * element will be inserted into the array.
1530     *
1531     * <p>
1532     * This method returns {@code null} for a {@code null} input array.
1533     * </p>
1534     *
1535     * @param array an {@link Object} array
1536     * @return a {@link Class} array, {@code null} if null array input
1537     * @since 2.4
1538     */
1539    public static Class<?>[] toClass(final Object... array) {
1540        if (array == null) {
1541            return null;
1542        }
1543        if (array.length == 0) {
1544            return ArrayUtils.EMPTY_CLASS_ARRAY;
1545        }
1546        final Class<?>[] classes = new Class[array.length];
1547        Arrays.setAll(classes, i -> array[i] == null ? null : array[i].getClass());
1548        return classes;
1549    }
1550
1551    /**
1552     * Decides if the part that was just copied to its destination location in the work array can be kept as it was copied
1553     * 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
1554     * case the {@code source} index, from where the characters are copied points one position after the last character,
1555     * a.k.a. {@code source ==
1556     * originalLength}
1557     *
1558     * <p>
1559     * 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
1560     * character that are to be copied is less than or equal to the desired length.
1561     * </p>
1562     *
1563     * @param runAheadTarget the target index (where the characters were copied to) pointing after the last character copied
1564     *        when the current part was copied
1565     * @param source the source index (where the characters were copied from) pointing after the last character copied when
1566     *        the current part was copied
1567     * @param originalLength the original length of the class full name, which is abbreviated
1568     * @param desiredLength the desired length of the abbreviated class name
1569     * @return {@code true} if it can be kept in its original length {@code false} if the current part has to be abbreviated
1570     *         and
1571     */
1572    private static boolean useFull(final int runAheadTarget, final int source, final int originalLength, final int desiredLength) {
1573        return source >= originalLength || runAheadTarget + originalLength - source <= desiredLength;
1574    }
1575
1576    /**
1577     * Converts the specified array of wrapper Class objects to an array of its corresponding primitive Class objects.
1578     *
1579     * <p>
1580     * This method invokes {@code wrapperToPrimitive()} for each element of the passed in array.
1581     * </p>
1582     *
1583     * @param classes the class array to convert, may be null or empty
1584     * @return an array which contains for each given class, the primitive class or <strong>null</strong> if the original class is not
1585     *         a wrapper class. {@code null} if null input. Empty array if an empty array passed in.
1586     * @see #wrapperToPrimitive(Class)
1587     * @since 2.4
1588     */
1589    public static Class<?>[] wrappersToPrimitives(final Class<?>... classes) {
1590        if (classes == null) {
1591            return null;
1592        }
1593
1594        if (classes.length == 0) {
1595            return classes;
1596        }
1597
1598        final Class<?>[] convertedClasses = new Class[classes.length];
1599        Arrays.setAll(convertedClasses, i -> wrapperToPrimitive(classes[i]));
1600        return convertedClasses;
1601    }
1602
1603    /**
1604     * Converts the specified wrapper class to its corresponding primitive class.
1605     *
1606     * <p>
1607     * This method is the counter part of {@code primitiveToWrapper()}. If the passed in class is a wrapper class for a
1608     * primitive type, this primitive type will be returned (e.g. {@code Integer.TYPE} for {@code Integer.class}). For other
1609     * classes, or if the parameter is <strong>null</strong>, the return value is <strong>null</strong>.
1610     * </p>
1611     *
1612     * @param cls the class to convert, may be <strong>null</strong>
1613     * @return the corresponding primitive type if {@code cls} is a wrapper class, <strong>null</strong> otherwise
1614     * @see #primitiveToWrapper(Class)
1615     * @since 2.4
1616     */
1617    public static Class<?> wrapperToPrimitive(final Class<?> cls) {
1618        return WRAPPER_PRIMITIVE_MAP.get(cls);
1619    }
1620
1621    /**
1622     * ClassUtils instances should NOT be constructed in standard programming. Instead, the class should be used as
1623     * {@code ClassUtils.getShortClassName(cls)}.
1624     *
1625     * <p>
1626     * This constructor is public to permit tools that require a JavaBean instance to operate.
1627     * </p>
1628     *
1629     * @deprecated TODO Make private in 4.0.
1630     */
1631    @Deprecated
1632    public ClassUtils() {
1633        // empty
1634    }
1635
1636}