    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}