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 *      http://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.Collections;
023import java.util.HashMap;
024import java.util.HashSet;
025import java.util.Iterator;
026import java.util.LinkedHashSet;
027import java.util.List;
028import java.util.Map;
029import java.util.Set;
030
031import org.apache.commons.lang3.mutable.MutableObject;
032
033/**
034 * <p>Operates on classes without using reflection.</p>
035 *
036 * <p>This class handles invalid {@code null} inputs as best it can.
037 * Each method documents its behaviour in more detail.</p>
038 *
039 * <p>The notion of a {@code canonical name} includes the human
040 * readable name for the type, for example {@code int[]}. The
041 * non-canonical method variants work with the JVM names, such as
042 * {@code [I}. </p>
043 *
044 * @since 2.0
045 * @version $Id: ClassUtils.java 1534839 2013-10-22 22:48:58Z mbenson $
046 */
047public class ClassUtils {
048    /**
049     * Inclusivity literals for {@link #hierarchy(Class, Interfaces)}.
050     * @since 3.2
051     */
052    public enum Interfaces {
053        INCLUDE, EXCLUDE;
054    }
055
056    /**
057     * The package separator character: <code>'&#x2e;' == {@value}</code>.
058     */
059    public static final char PACKAGE_SEPARATOR_CHAR = '.';
060
061    /**
062     * The package separator String: <code>"&#x2e;"</code>.
063     */
064    public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);
065
066    /**
067     * The inner class separator character: <code>'$' == {@value}</code>.
068     */
069    public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
070
071    /**
072     * The inner class separator String: {@code "$"}.
073     */
074    public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
075
076    /**
077     * Maps primitive {@code Class}es to their corresponding wrapper {@code Class}.
078     */
079    private static final Map<Class<?>, Class<?>> primitiveWrapperMap = new HashMap<Class<?>, Class<?>>();
080    static {
081         primitiveWrapperMap.put(Boolean.TYPE, Boolean.class);
082         primitiveWrapperMap.put(Byte.TYPE, Byte.class);
083         primitiveWrapperMap.put(Character.TYPE, Character.class);
084         primitiveWrapperMap.put(Short.TYPE, Short.class);
085         primitiveWrapperMap.put(Integer.TYPE, Integer.class);
086         primitiveWrapperMap.put(Long.TYPE, Long.class);
087         primitiveWrapperMap.put(Double.TYPE, Double.class);
088         primitiveWrapperMap.put(Float.TYPE, Float.class);
089         primitiveWrapperMap.put(Void.TYPE, Void.TYPE);
090    }
091
092    /**
093     * Maps wrapper {@code Class}es to their corresponding primitive types.
094     */
095    private static final Map<Class<?>, Class<?>> wrapperPrimitiveMap = new HashMap<Class<?>, Class<?>>();
096    static {
097        for (final Class<?> primitiveClass : primitiveWrapperMap.keySet()) {
098            final Class<?> wrapperClass = primitiveWrapperMap.get(primitiveClass);
099            if (!primitiveClass.equals(wrapperClass)) {
100                wrapperPrimitiveMap.put(wrapperClass, primitiveClass);
101            }
102        }
103    }
104
105    /**
106     * Maps a primitive class name to its corresponding abbreviation used in array class names.
107     */
108    private static final Map<String, String> abbreviationMap;
109
110    /**
111     * Maps an abbreviation used in array class names to corresponding primitive class name.
112     */
113    private static final Map<String, String> reverseAbbreviationMap;
114
115    /**
116     * Feed abbreviation maps
117     */
118    static {
119        final Map<String, String> m = new HashMap<String, String>();
120        m.put("int", "I");
121        m.put("boolean", "Z");
122        m.put("float", "F");
123        m.put("long", "J");
124        m.put("short", "S");
125        m.put("byte", "B");
126        m.put("double", "D");
127        m.put("char", "C");
128        m.put("void", "V");
129        final Map<String, String> r = new HashMap<String, String>();
130        for (Map.Entry<String, String> e : m.entrySet()) {
131            r.put(e.getValue(), e.getKey());
132        }
133        abbreviationMap = Collections.unmodifiableMap(m);
134        reverseAbbreviationMap = Collections.unmodifiableMap(r);
135    }
136
137    /**
138     * <p>ClassUtils instances should NOT be constructed in standard programming.
139     * Instead, the class should be used as
140     * {@code ClassUtils.getShortClassName(cls)}.</p>
141     *
142     * <p>This constructor is public to permit tools that require a JavaBean
143     * instance to operate.</p>
144     */
145    public ClassUtils() {
146      super();
147    }
148
149    // Short class name
150    // ----------------------------------------------------------------------
151    /**
152     * <p>Gets the class name minus the package name for an {@code Object}.</p>
153     *
154     * @param object  the class to get the short name for, may be null
155     * @param valueIfNull  the value to return if null
156     * @return the class name of the object without the package name, or the null value
157     */
158    public static String getShortClassName(final Object object, final String valueIfNull) {
159        if (object == null) {
160            return valueIfNull;
161        }
162        return getShortClassName(object.getClass());
163    }
164
165    /**
166     * <p>Gets the class name minus the package name from a {@code Class}.</p>
167     *
168     * <p>Consider using the Java 5 API {@link Class#getSimpleName()} instead.
169     * The one known difference is that this code will return {@code "Map.Entry"} while
170     * the {@code java.lang.Class} variant will simply return {@code "Entry"}. </p>
171     *
172     * @param cls  the class to get the short name for.
173     * @return the class name without the package name or an empty string
174     */
175    public static String getShortClassName(final Class<?> cls) {
176        if (cls == null) {
177            return StringUtils.EMPTY;
178        }
179        return getShortClassName(cls.getName());
180    }
181
182    /**
183     * <p>Gets the class name minus the package name from a String.</p>
184     *
185     * <p>The string passed in is assumed to be a class name - it is not checked.</p>
186
187     * <p>Note that this method differs from Class.getSimpleName() in that this will
188     * return {@code "Map.Entry"} whilst the {@code java.lang.Class} variant will simply
189     * return {@code "Entry"}. </p>
190     *
191     * @param className  the className to get the short name for
192     * @return the class name of the class without the package name or an empty string
193     */
194    public static String getShortClassName(String className) {
195        if (StringUtils.isEmpty(className)) {
196            return StringUtils.EMPTY;
197        }
198
199        final StringBuilder arrayPrefix = new StringBuilder();
200
201        // Handle array encoding
202        if (className.startsWith("[")) {
203            while (className.charAt(0) == '[') {
204                className = className.substring(1);
205                arrayPrefix.append("[]");
206            }
207            // Strip Object type encoding
208            if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
209                className = className.substring(1, className.length() - 1);
210            }
211
212            if (reverseAbbreviationMap.containsKey(className)) {
213                className = reverseAbbreviationMap.get(className);
214            }
215        }
216
217        final int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
218        final int innerIdx = className.indexOf(
219                INNER_CLASS_SEPARATOR_CHAR, lastDotIdx == -1 ? 0 : lastDotIdx + 1);
220        String out = className.substring(lastDotIdx + 1);
221        if (innerIdx != -1) {
222            out = out.replace(INNER_CLASS_SEPARATOR_CHAR, PACKAGE_SEPARATOR_CHAR);
223        }
224        return out + arrayPrefix;
225    }
226
227    /**
228     * <p>Null-safe version of <code>aClass.getSimpleName()</code></p>
229     *
230     * @param cls the class for which to get the simple name.
231     * @return the simple class name.
232     * @since 3.0
233     * @see Class#getSimpleName()
234     */
235    public static String getSimpleName(final Class<?> cls) {
236        if (cls == null) {
237            return StringUtils.EMPTY;
238        }
239        return cls.getSimpleName();
240    }
241
242    /**
243     * <p>Null-safe version of <code>aClass.getSimpleName()</code></p>
244     *
245     * @param object the object for which to get the simple class name.
246     * @param valueIfNull the value to return if <code>object</code> is <code>null</code>
247     * @return the simple class name.
248     * @since 3.0
249     * @see Class#getSimpleName()
250     */
251    public static String getSimpleName(final Object object, final String valueIfNull) {
252        if (object == null) {
253            return valueIfNull;
254        }
255        return getSimpleName(object.getClass());
256    }
257
258    // Package name
259    // ----------------------------------------------------------------------
260    /**
261     * <p>Gets the package name of an {@code Object}.</p>
262     *
263     * @param object  the class to get the package name for, may be null
264     * @param valueIfNull  the value to return if null
265     * @return the package name of the object, or the null value
266     */
267    public static String getPackageName(final Object object, final String valueIfNull) {
268        if (object == null) {
269            return valueIfNull;
270        }
271        return getPackageName(object.getClass());
272    }
273
274    /**
275     * <p>Gets the package name of a {@code Class}.</p>
276     *
277     * @param cls  the class to get the package name for, may be {@code null}.
278     * @return the package name or an empty string
279     */
280    public static String getPackageName(final Class<?> cls) {
281        if (cls == null) {
282            return StringUtils.EMPTY;
283        }
284        return getPackageName(cls.getName());
285    }
286
287    /**
288     * <p>Gets the package name from a {@code String}.</p>
289     *
290     * <p>The string passed in is assumed to be a class name - it is not checked.</p>
291     * <p>If the class is unpackaged, return an empty string.</p>
292     *
293     * @param className  the className to get the package name for, may be {@code null}
294     * @return the package name or an empty string
295     */
296    public static String getPackageName(String className) {
297        if (StringUtils.isEmpty(className)) {
298            return StringUtils.EMPTY;
299        }
300
301        // Strip array encoding
302        while (className.charAt(0) == '[') {
303            className = className.substring(1);
304        }
305        // Strip Object type encoding
306        if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
307            className = className.substring(1);
308        }
309
310        final int i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
311        if (i == -1) {
312            return StringUtils.EMPTY;
313        }
314        return className.substring(0, i);
315    }
316
317    // Superclasses/Superinterfaces
318    // ----------------------------------------------------------------------
319    /**
320     * <p>Gets a {@code List} of superclasses for the given class.</p>
321     *
322     * @param cls  the class to look up, may be {@code null}
323     * @return the {@code List} of superclasses in order going up from this one
324     *  {@code null} if null input
325     */
326    public static List<Class<?>> getAllSuperclasses(final Class<?> cls) {
327        if (cls == null) {
328            return null;
329        }
330        final List<Class<?>> classes = new ArrayList<Class<?>>();
331        Class<?> superclass = cls.getSuperclass();
332        while (superclass != null) {
333            classes.add(superclass);
334            superclass = superclass.getSuperclass();
335        }
336        return classes;
337    }
338
339    /**
340     * <p>Gets a {@code List} of all interfaces implemented by the given
341     * class and its superclasses.</p>
342     *
343     * <p>The order is determined by looking through each interface in turn as
344     * declared in the source file and following its hierarchy up. Then each
345     * superclass is considered in the same way. Later duplicates are ignored,
346     * so the order is maintained.</p>
347     *
348     * @param cls  the class to look up, may be {@code null}
349     * @return the {@code List} of interfaces in order,
350     *  {@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<Class<?>>();
358        getAllInterfaces(cls, interfacesFound);
359
360        return new ArrayList<Class<?>>(interfacesFound);
361    }
362
363    /**
364     * Get the interfaces for the specified class.
365     *
366     * @param cls  the class to look up, may be {@code null}
367     * @param interfacesFound the {@code 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    // Convert list
384    // ----------------------------------------------------------------------
385    /**
386     * <p>Given a {@code List} of class names, this method converts them into classes.</p>
387     *
388     * <p>A new {@code List} is returned. If the class name cannot be found, {@code null}
389     * is stored in the {@code List}. If the class name in the {@code List} is
390     * {@code null}, {@code null} is stored in the output {@code List}.</p>
391     *
392     * @param classNames  the classNames to change
393     * @return a {@code List} of Class objects corresponding to the class names,
394     *  {@code null} if null input
395     * @throws ClassCastException if classNames contains a non String entry
396     */
397    public static List<Class<?>> convertClassNamesToClasses(final List<String> classNames) {
398        if (classNames == null) {
399            return null;
400        }
401        final List<Class<?>> classes = new ArrayList<Class<?>>(classNames.size());
402        for (final String className : classNames) {
403            try {
404                classes.add(Class.forName(className));
405            } catch (final Exception ex) {
406                classes.add(null);
407            }
408        }
409        return classes;
410    }
411
412    /**
413     * <p>Given a {@code List} of {@code Class} objects, this method converts
414     * them into class names.</p>
415     *
416     * <p>A new {@code List} is returned. {@code null} objects will be copied into
417     * the returned list as {@code null}.</p>
418     *
419     * @param classes  the classes to change
420     * @return a {@code List} of class names corresponding to the Class objects,
421     *  {@code null} if null input
422     * @throws ClassCastException if {@code classes} contains a non-{@code Class} entry
423     */
424    public static List<String> convertClassesToClassNames(final List<Class<?>> classes) {
425        if (classes == null) {
426            return null;
427        }
428        final List<String> classNames = new ArrayList<String>(classes.size());
429        for (final Class<?> cls : classes) {
430            if (cls == null) {
431                classNames.add(null);
432            } else {
433                classNames.add(cls.getName());
434            }
435        }
436        return classNames;
437    }
438
439    // Is assignable
440    // ----------------------------------------------------------------------
441    /**
442     * <p>Checks if an array of Classes can be assigned to another array of Classes.</p>
443     *
444     * <p>This method calls {@link #isAssignable(Class, Class) isAssignable} for each
445     * Class pair in the input arrays. It can be used to check if a set of arguments
446     * (the first parameter) are suitably compatible with a set of method parameter types
447     * (the second parameter).</p>
448     *
449     * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
450     * method takes into account widenings of primitive classes and
451     * {@code null}s.</p>
452     *
453     * <p>Primitive widenings allow an int to be assigned to a {@code long},
454     * {@code float} or {@code double}. This method returns the correct
455     * result for these cases.</p>
456     *
457     * <p>{@code Null} may be assigned to any reference type. This method will
458     * return {@code true} if {@code null} is passed in and the toClass is
459     * non-primitive.</p>
460     *
461     * <p>Specifically, this method tests whether the type represented by the
462     * specified {@code Class} parameter can be converted to the type
463     * represented by this {@code Class} object via an identity conversion
464     * widening primitive or widening reference conversion. See
465     * <em><a href="http://docs.oracle.com/javase/specs/">The Java Language Specification</a></em>,
466     * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
467     *
468     * <p><strong>Since Lang 3.0,</strong> this method will default behavior for
469     * calculating assignability between primitive and wrapper types <em>corresponding
470     * to the running Java version</em>; i.e. autoboxing will be the default
471     * behavior in VMs running Java versions >= 1.5.</p>
472     *
473     * @param classArray  the array of Classes to check, may be {@code null}
474     * @param toClassArray  the array of Classes to try to assign into, may be {@code null}
475     * @return {@code true} if assignment possible
476     */
477    public static boolean isAssignable(final Class<?>[] classArray, final Class<?>... toClassArray) {
478        return isAssignable(classArray, toClassArray, SystemUtils.isJavaVersionAtLeast(JavaVersion.JAVA_1_5));
479    }
480
481    /**
482     * <p>Checks if an array of Classes can be assigned to another array of Classes.</p>
483     *
484     * <p>This method calls {@link #isAssignable(Class, Class) isAssignable} for each
485     * Class pair in the input arrays. It can be used to check if a set of arguments
486     * (the first parameter) are suitably compatible with a set of method parameter types
487     * (the second parameter).</p>
488     *
489     * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
490     * method takes into account widenings of primitive classes and
491     * {@code null}s.</p>
492     *
493     * <p>Primitive widenings allow an int to be assigned to a {@code long},
494     * {@code float} or {@code double}. This method returns the correct
495     * result for these cases.</p>
496     *
497     * <p>{@code Null} may be assigned to any reference type. This method will
498     * return {@code true} if {@code null} is passed in and the toClass is
499     * non-primitive.</p>
500     *
501     * <p>Specifically, this method tests whether the type represented by the
502     * specified {@code Class} parameter can be converted to the type
503     * represented by this {@code Class} object via an identity conversion
504     * widening primitive or widening reference conversion. See
505     * <em><a href="http://docs.oracle.com/javase/specs/">The Java Language Specification</a></em>,
506     * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
507     *
508     * @param classArray  the array of Classes to check, may be {@code null}
509     * @param toClassArray  the array of Classes to try to assign into, may be {@code null}
510     * @param autoboxing  whether to use implicit autoboxing/unboxing between primitives and wrappers
511     * @return {@code true} if assignment possible
512     */
513    public static boolean isAssignable(Class<?>[] classArray, Class<?>[] toClassArray, final boolean autoboxing) {
514        if (ArrayUtils.isSameLength(classArray, toClassArray) == false) {
515            return false;
516        }
517        if (classArray == null) {
518            classArray = ArrayUtils.EMPTY_CLASS_ARRAY;
519        }
520        if (toClassArray == null) {
521            toClassArray = ArrayUtils.EMPTY_CLASS_ARRAY;
522        }
523        for (int i = 0; i < classArray.length; i++) {
524            if (isAssignable(classArray[i], toClassArray[i], autoboxing) == false) {
525                return false;
526            }
527        }
528        return true;
529    }
530
531    /**
532     * Returns whether the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
533     * {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
534     *
535     * @param type
536     *            The class to query or null.
537     * @return true if the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
538     *         {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
539     * @since 3.1
540     */
541    public static boolean isPrimitiveOrWrapper(final Class<?> type) {
542        if (type == null) {
543            return false;
544        }
545        return type.isPrimitive() || isPrimitiveWrapper(type);
546    }
547
548    /**
549     * Returns whether the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character}, {@link Short},
550     * {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
551     *
552     * @param type
553     *            The class to query or null.
554     * @return true if the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character}, {@link Short},
555     *         {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
556     * @since 3.1
557     */
558    public static boolean isPrimitiveWrapper(final Class<?> type) {
559        return wrapperPrimitiveMap.containsKey(type);
560    }
561
562    /**
563     * <p>Checks if one {@code Class} can be assigned to a variable of
564     * another {@code Class}.</p>
565     *
566     * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method,
567     * this method takes into account widenings of primitive classes and
568     * {@code null}s.</p>
569     *
570     * <p>Primitive widenings allow an int to be assigned to a long, float or
571     * double. This method returns the correct result for these cases.</p>
572     *
573     * <p>{@code Null} may be assigned to any reference type. This method
574     * will return {@code true} if {@code null} is passed in and the
575     * toClass is non-primitive.</p>
576     *
577     * <p>Specifically, this method tests whether the type represented by the
578     * specified {@code Class} parameter can be converted to the type
579     * represented by this {@code Class} object via an identity conversion
580     * widening primitive or widening reference conversion. See
581     * <em><a href="http://docs.oracle.com/javase/specs/">The Java Language Specification</a></em>,
582     * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
583     *
584     * <p><strong>Since Lang 3.0,</strong> this method will default behavior for
585     * calculating assignability between primitive and wrapper types <em>corresponding
586     * to the running Java version</em>; i.e. autoboxing will be the default
587     * behavior in VMs running Java versions >= 1.5.</p>
588     *
589     * @param cls  the Class to check, may be null
590     * @param toClass  the Class to try to assign into, returns false if null
591     * @return {@code true} if assignment possible
592     */
593    public static boolean isAssignable(final Class<?> cls, final Class<?> toClass) {
594        return isAssignable(cls, toClass, SystemUtils.isJavaVersionAtLeast(JavaVersion.JAVA_1_5));
595    }
596
597    /**
598     * <p>Checks if one {@code Class} can be assigned to a variable of
599     * another {@code Class}.</p>
600     *
601     * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method,
602     * this method takes into account widenings of primitive classes and
603     * {@code null}s.</p>
604     *
605     * <p>Primitive widenings allow an int to be assigned to a long, float or
606     * double. This method returns the correct result for these cases.</p>
607     *
608     * <p>{@code Null} may be assigned to any reference type. This method
609     * will return {@code true} if {@code null} is passed in and the
610     * toClass is non-primitive.</p>
611     *
612     * <p>Specifically, this method tests whether the type represented by the
613     * specified {@code Class} parameter can be converted to the type
614     * represented by this {@code Class} object via an identity conversion
615     * widening primitive or widening reference conversion. See
616     * <em><a href="http://docs.oracle.com/javase/specs/">The Java Language Specification</a></em>,
617     * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
618     *
619     * @param cls  the Class to check, may be null
620     * @param toClass  the Class to try to assign into, returns false if null
621     * @param autoboxing  whether to use implicit autoboxing/unboxing between primitives and wrappers
622     * @return {@code true} if assignment possible
623     */
624    public static boolean isAssignable(Class<?> cls, final Class<?> toClass, final boolean autoboxing) {
625        if (toClass == null) {
626            return false;
627        }
628        // have to check for null, as isAssignableFrom doesn't
629        if (cls == null) {
630            return !toClass.isPrimitive();
631        }
632        //autoboxing:
633        if (autoboxing) {
634            if (cls.isPrimitive() && !toClass.isPrimitive()) {
635                cls = primitiveToWrapper(cls);
636                if (cls == null) {
637                    return false;
638                }
639            }
640            if (toClass.isPrimitive() && !cls.isPrimitive()) {
641                cls = wrapperToPrimitive(cls);
642                if (cls == null) {
643                    return false;
644                }
645            }
646        }
647        if (cls.equals(toClass)) {
648            return true;
649        }
650        if (cls.isPrimitive()) {
651            if (toClass.isPrimitive() == false) {
652                return false;
653            }
654            if (Integer.TYPE.equals(cls)) {
655                return Long.TYPE.equals(toClass)
656                    || Float.TYPE.equals(toClass)
657                    || Double.TYPE.equals(toClass);
658            }
659            if (Long.TYPE.equals(cls)) {
660                return Float.TYPE.equals(toClass)
661                    || Double.TYPE.equals(toClass);
662            }
663            if (Boolean.TYPE.equals(cls)) {
664                return false;
665            }
666            if (Double.TYPE.equals(cls)) {
667                return false;
668            }
669            if (Float.TYPE.equals(cls)) {
670                return Double.TYPE.equals(toClass);
671            }
672            if (Character.TYPE.equals(cls)) {
673                return Integer.TYPE.equals(toClass)
674                    || Long.TYPE.equals(toClass)
675                    || Float.TYPE.equals(toClass)
676                    || Double.TYPE.equals(toClass);
677            }
678            if (Short.TYPE.equals(cls)) {
679                return Integer.TYPE.equals(toClass)
680                    || Long.TYPE.equals(toClass)
681                    || Float.TYPE.equals(toClass)
682                    || Double.TYPE.equals(toClass);
683            }
684            if (Byte.TYPE.equals(cls)) {
685                return Short.TYPE.equals(toClass)
686                    || Integer.TYPE.equals(toClass)
687                    || Long.TYPE.equals(toClass)
688                    || Float.TYPE.equals(toClass)
689                    || Double.TYPE.equals(toClass);
690            }
691            // should never get here
692            return false;
693        }
694        return toClass.isAssignableFrom(cls);
695    }
696
697    /**
698     * <p>Converts the specified primitive Class object to its corresponding
699     * wrapper Class object.</p>
700     *
701     * <p>NOTE: From v2.2, this method handles {@code Void.TYPE},
702     * returning {@code Void.TYPE}.</p>
703     *
704     * @param cls  the class to convert, may be null
705     * @return the wrapper class for {@code cls} or {@code cls} if
706     * {@code cls} is not a primitive. {@code null} if null input.
707     * @since 2.1
708     */
709    public static Class<?> primitiveToWrapper(final Class<?> cls) {
710        Class<?> convertedClass = cls;
711        if (cls != null && cls.isPrimitive()) {
712            convertedClass = primitiveWrapperMap.get(cls);
713        }
714        return convertedClass;
715    }
716
717    /**
718     * <p>Converts the specified array of primitive Class objects to an array of
719     * its corresponding wrapper Class objects.</p>
720     *
721     * @param classes  the class array to convert, may be null or empty
722     * @return an array which contains for each given class, the wrapper class or
723     * the original class if class is not a primitive. {@code null} if null input.
724     * Empty array if an empty array passed in.
725     * @since 2.1
726     */
727    public static Class<?>[] primitivesToWrappers(final Class<?>... classes) {
728        if (classes == null) {
729            return null;
730        }
731
732        if (classes.length == 0) {
733            return classes;
734        }
735
736        final Class<?>[] convertedClasses = new Class[classes.length];
737        for (int i = 0; i < classes.length; i++) {
738            convertedClasses[i] = primitiveToWrapper(classes[i]);
739        }
740        return convertedClasses;
741    }
742
743    /**
744     * <p>Converts the specified wrapper class to its corresponding primitive
745     * class.</p>
746     *
747     * <p>This method is the counter part of {@code primitiveToWrapper()}.
748     * If the passed in class is a wrapper class for a primitive type, this
749     * primitive type will be returned (e.g. {@code Integer.TYPE} for
750     * {@code Integer.class}). For other classes, or if the parameter is
751     * <b>null</b>, the return value is <b>null</b>.</p>
752     *
753     * @param cls the class to convert, may be <b>null</b>
754     * @return the corresponding primitive type if {@code cls} is a
755     * wrapper class, <b>null</b> otherwise
756     * @see #primitiveToWrapper(Class)
757     * @since 2.4
758     */
759    public static Class<?> wrapperToPrimitive(final Class<?> cls) {
760        return wrapperPrimitiveMap.get(cls);
761    }
762
763    /**
764     * <p>Converts the specified array of wrapper Class objects to an array of
765     * its corresponding primitive Class objects.</p>
766     *
767     * <p>This method invokes {@code wrapperToPrimitive()} for each element
768     * of the passed in array.</p>
769     *
770     * @param classes  the class array to convert, may be null or empty
771     * @return an array which contains for each given class, the primitive class or
772     * <b>null</b> if the original class is not a wrapper class. {@code null} if null input.
773     * Empty array if an empty array passed in.
774     * @see #wrapperToPrimitive(Class)
775     * @since 2.4
776     */
777    public static Class<?>[] wrappersToPrimitives(final Class<?>... classes) {
778        if (classes == null) {
779            return null;
780        }
781
782        if (classes.length == 0) {
783            return classes;
784        }
785
786        final Class<?>[] convertedClasses = new Class[classes.length];
787        for (int i = 0; i < classes.length; i++) {
788            convertedClasses[i] = wrapperToPrimitive(classes[i]);
789        }
790        return convertedClasses;
791    }
792
793    // Inner class
794    // ----------------------------------------------------------------------
795    /**
796     * <p>Is the specified class an inner class or static nested class.</p>
797     *
798     * @param cls  the class to check, may be null
799     * @return {@code true} if the class is an inner or static nested class,
800     *  false if not or {@code null}
801     */
802    public static boolean isInnerClass(final Class<?> cls) {
803        return cls != null && cls.getEnclosingClass() != null;
804    }
805
806    // Class loading
807    // ----------------------------------------------------------------------
808    /**
809     * Returns the class represented by {@code className} using the
810     * {@code classLoader}.  This implementation supports the syntaxes
811     * "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
812     * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
813     *
814     * @param classLoader  the class loader to use to load the class
815     * @param className  the class name
816     * @param initialize  whether the class must be initialized
817     * @return the class represented by {@code className} using the {@code classLoader}
818     * @throws ClassNotFoundException if the class is not found
819     */
820    public static Class<?> getClass(
821            final ClassLoader classLoader, final String className, final boolean initialize) throws ClassNotFoundException {
822        try {
823            Class<?> clazz;
824            if (abbreviationMap.containsKey(className)) {
825                final String clsName = "[" + abbreviationMap.get(className);
826                clazz = Class.forName(clsName, initialize, classLoader).getComponentType();
827            } else {
828                clazz = Class.forName(toCanonicalName(className), initialize, classLoader);
829            }
830            return clazz;
831        } catch (final ClassNotFoundException ex) {
832            // allow path separators (.) as inner class name separators
833            final int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
834
835            if (lastDotIndex != -1) {
836                try {
837                    return getClass(classLoader, className.substring(0, lastDotIndex) +
838                            INNER_CLASS_SEPARATOR_CHAR + className.substring(lastDotIndex + 1),
839                            initialize);
840                } catch (final ClassNotFoundException ex2) { // NOPMD
841                    // ignore exception
842                }
843            }
844
845            throw ex;
846        }
847    }
848
849    /**
850     * Returns the (initialized) class represented by {@code className}
851     * using the {@code classLoader}.  This implementation supports
852     * the syntaxes "{@code java.util.Map.Entry[]}",
853     * "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}",
854     * and "{@code [Ljava.util.Map$Entry;}".
855     *
856     * @param classLoader  the class loader to use to load the class
857     * @param className  the class name
858     * @return the class represented by {@code className} using the {@code classLoader}
859     * @throws ClassNotFoundException if the class is not found
860     */
861    public static Class<?> getClass(final ClassLoader classLoader, final String className) throws ClassNotFoundException {
862        return getClass(classLoader, className, true);
863    }
864
865    /**
866     * Returns the (initialized) class represented by {@code className}
867     * using the current thread's context class loader. This implementation
868     * supports the syntaxes "{@code java.util.Map.Entry[]}",
869     * "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}",
870     * and "{@code [Ljava.util.Map$Entry;}".
871     *
872     * @param className  the class name
873     * @return the class represented by {@code className} using the current thread's context class loader
874     * @throws ClassNotFoundException if the class is not found
875     */
876    public static Class<?> getClass(final String className) throws ClassNotFoundException {
877        return getClass(className, true);
878    }
879
880    /**
881     * Returns the class represented by {@code className} using the
882     * current thread's context class loader. This implementation supports the
883     * syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
884     * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
885     *
886     * @param className  the class name
887     * @param initialize  whether the class must be initialized
888     * @return the class represented by {@code className} using the current thread's context class loader
889     * @throws ClassNotFoundException if the class is not found
890     */
891    public static Class<?> getClass(final String className, final boolean initialize) throws ClassNotFoundException {
892        final ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
893        final ClassLoader loader = contextCL == null ? ClassUtils.class.getClassLoader() : contextCL;
894        return getClass(loader, className, initialize);
895    }
896
897    // Public method
898    // ----------------------------------------------------------------------
899    /**
900     * <p>Returns the desired Method much like {@code Class.getMethod}, however
901     * it ensures that the returned Method is from a public class or interface and not
902     * from an anonymous inner class. This means that the Method is invokable and
903     * doesn't fall foul of Java bug
904     * <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4071957">4071957</a>).
905     *
906     *  <code><pre>Set set = Collections.unmodifiableSet(...);
907     *  Method method = ClassUtils.getPublicMethod(set.getClass(), "isEmpty",  new Class[0]);
908     *  Object result = method.invoke(set, new Object[]);</pre></code>
909     * </p>
910     *
911     * @param cls  the class to check, not null
912     * @param methodName  the name of the method
913     * @param parameterTypes  the list of parameters
914     * @return the method
915     * @throws NullPointerException if the class is null
916     * @throws SecurityException if a security violation occurred
917     * @throws NoSuchMethodException if the method is not found in the given class
918     *  or if the metothod doen't conform with the requirements
919     */
920    public static Method getPublicMethod(final Class<?> cls, final String methodName, final Class<?>... parameterTypes)
921            throws SecurityException, NoSuchMethodException {
922
923        final Method declaredMethod = cls.getMethod(methodName, parameterTypes);
924        if (Modifier.isPublic(declaredMethod.getDeclaringClass().getModifiers())) {
925            return declaredMethod;
926        }
927
928        final List<Class<?>> candidateClasses = new ArrayList<Class<?>>();
929        candidateClasses.addAll(getAllInterfaces(cls));
930        candidateClasses.addAll(getAllSuperclasses(cls));
931
932        for (final Class<?> candidateClass : candidateClasses) {
933            if (!Modifier.isPublic(candidateClass.getModifiers())) {
934                continue;
935            }
936            Method candidateMethod;
937            try {
938                candidateMethod = candidateClass.getMethod(methodName, parameterTypes);
939            } catch (final NoSuchMethodException ex) {
940                continue;
941            }
942            if (Modifier.isPublic(candidateMethod.getDeclaringClass().getModifiers())) {
943                return candidateMethod;
944            }
945        }
946
947        throw new NoSuchMethodException("Can't find a public method for " +
948                methodName + " " + ArrayUtils.toString(parameterTypes));
949    }
950
951    // ----------------------------------------------------------------------
952    /**
953     * Converts a class name to a JLS style class name.
954     *
955     * @param className  the class name
956     * @return the converted name
957     */
958    private static String toCanonicalName(String className) {
959        className = StringUtils.deleteWhitespace(className);
960        if (className == null) {
961            throw new NullPointerException("className must not be null.");
962        } else if (className.endsWith("[]")) {
963            final StringBuilder classNameBuffer = new StringBuilder();
964            while (className.endsWith("[]")) {
965                className = className.substring(0, className.length() - 2);
966                classNameBuffer.append("[");
967            }
968            final String abbreviation = abbreviationMap.get(className);
969            if (abbreviation != null) {
970                classNameBuffer.append(abbreviation);
971            } else {
972                classNameBuffer.append("L").append(className).append(";");
973            }
974            className = classNameBuffer.toString();
975        }
976        return className;
977    }
978
979    /**
980     * <p>Converts an array of {@code Object} in to an array of {@code Class} objects.
981     * If any of these objects is null, a null element will be inserted into the array.</p>
982     *
983     * <p>This method returns {@code null} for a {@code null} input array.</p>
984     *
985     * @param array an {@code Object} array
986     * @return a {@code Class} array, {@code null} if null array input
987     * @since 2.4
988     */
989    public static Class<?>[] toClass(final Object... array) {
990        if (array == null) {
991            return null;
992        } else if (array.length == 0) {
993            return ArrayUtils.EMPTY_CLASS_ARRAY;
994        }
995        final Class<?>[] classes = new Class[array.length];
996        for (int i = 0; i < array.length; i++) {
997            classes[i] = array[i] == null ? null : array[i].getClass();
998        }
999        return classes;
1000    }
1001
1002    // Short canonical name
1003    // ----------------------------------------------------------------------
1004    /**
1005     * <p>Gets the canonical name minus the package name for an {@code Object}.</p>
1006     *
1007     * @param object  the class to get the short name for, may be null
1008     * @param valueIfNull  the value to return if null
1009     * @return the canonical name of the object without the package name, or the null value
1010     * @since 2.4
1011     */
1012    public static String getShortCanonicalName(final Object object, final String valueIfNull) {
1013        if (object == null) {
1014            return valueIfNull;
1015        }
1016        return getShortCanonicalName(object.getClass().getName());
1017    }
1018
1019    /**
1020     * <p>Gets the canonical name minus the package name from a {@code Class}.</p>
1021     *
1022     * @param cls  the class to get the short name for.
1023     * @return the canonical name without the package name or an empty string
1024     * @since 2.4
1025     */
1026    public static String getShortCanonicalName(final Class<?> cls) {
1027        if (cls == null) {
1028            return StringUtils.EMPTY;
1029        }
1030        return getShortCanonicalName(cls.getName());
1031    }
1032
1033    /**
1034     * <p>Gets the canonical name minus the package name from a String.</p>
1035     *
1036     * <p>The string passed in is assumed to be a canonical name - it is not checked.</p>
1037     *
1038     * @param canonicalName  the class name to get the short name for
1039     * @return the canonical name of the class without the package name or an empty string
1040     * @since 2.4
1041     */
1042    public static String getShortCanonicalName(final String canonicalName) {
1043        return ClassUtils.getShortClassName(getCanonicalName(canonicalName));
1044    }
1045
1046    // Package name
1047    // ----------------------------------------------------------------------
1048    /**
1049     * <p>Gets the package name from the canonical name of an {@code Object}.</p>
1050     *
1051     * @param object  the class to get the package name for, may be null
1052     * @param valueIfNull  the value to return if null
1053     * @return the package name of the object, or the null value
1054     * @since 2.4
1055     */
1056    public static String getPackageCanonicalName(final Object object, final String valueIfNull) {
1057        if (object == null) {
1058            return valueIfNull;
1059        }
1060        return getPackageCanonicalName(object.getClass().getName());
1061    }
1062
1063    /**
1064     * <p>Gets the package name from the canonical name of a {@code Class}.</p>
1065     *
1066     * @param cls  the class to get the package name for, may be {@code null}.
1067     * @return the package name or an empty string
1068     * @since 2.4
1069     */
1070    public static String getPackageCanonicalName(final Class<?> cls) {
1071        if (cls == null) {
1072            return StringUtils.EMPTY;
1073        }
1074        return getPackageCanonicalName(cls.getName());
1075    }
1076
1077    /**
1078     * <p>Gets the package name from the canonical name. </p>
1079     *
1080     * <p>The string passed in is assumed to be a canonical name - it is not checked.</p>
1081     * <p>If the class is unpackaged, return an empty string.</p>
1082     *
1083     * @param canonicalName  the canonical name to get the package name for, may be {@code null}
1084     * @return the package name or an empty string
1085     * @since 2.4
1086     */
1087    public static String getPackageCanonicalName(final String canonicalName) {
1088        return ClassUtils.getPackageName(getCanonicalName(canonicalName));
1089    }
1090
1091    /**
1092     * <p>Converts a given name of class into canonical format.
1093     * If name of class is not a name of array class it returns
1094     * unchanged name.</p>
1095     * <p>Example:
1096     * <ul>
1097     * <li>{@code getCanonicalName("[I") = "int[]"}</li>
1098     * <li>{@code getCanonicalName("[Ljava.lang.String;") = "java.lang.String[]"}</li>
1099     * <li>{@code getCanonicalName("java.lang.String") = "java.lang.String"}</li>
1100     * </ul>
1101     * </p>
1102     *
1103     * @param className the name of class
1104     * @return canonical form of class name
1105     * @since 2.4
1106     */
1107    private static String getCanonicalName(String className) {
1108        className = StringUtils.deleteWhitespace(className);
1109        if (className == null) {
1110            return null;
1111        } else {
1112            int dim = 0;
1113            while (className.startsWith("[")) {
1114                dim++;
1115                className = className.substring(1);
1116            }
1117            if (dim < 1) {
1118                return className;
1119            } else {
1120                if (className.startsWith("L")) {
1121                    className = className.substring(
1122                        1,
1123                        className.endsWith(";")
1124                            ? className.length() - 1
1125                            : className.length());
1126                } else {
1127                    if (className.length() > 0) {
1128                        className = reverseAbbreviationMap.get(className.substring(0, 1));
1129                    }
1130                }
1131                final StringBuilder canonicalClassNameBuffer = new StringBuilder(className);
1132                for (int i = 0; i < dim; i++) {
1133                    canonicalClassNameBuffer.append("[]");
1134                }
1135                return canonicalClassNameBuffer.toString();
1136            }
1137        }
1138    }
1139
1140    /**
1141     * Get an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order,
1142     * excluding interfaces.
1143     *
1144     * @param type the type to get the class hierarchy from
1145     * @return Iterable an Iterable over the class hierarchy of the given class
1146     * @since 3.2
1147     */
1148    public static Iterable<Class<?>> hierarchy(final Class<?> type) {
1149        return hierarchy(type, Interfaces.EXCLUDE);
1150    }
1151
1152    /**
1153     * Get an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order.
1154     *
1155     * @param type the type to get the class hierarchy from
1156     * @param interfacesBehavior switch indicating whether to include or exclude interfaces
1157     * @return Iterable an Iterable over the class hierarchy of the given class
1158     * @since 3.2
1159     */
1160    public static Iterable<Class<?>> hierarchy(final Class<?> type, Interfaces interfacesBehavior) {
1161        final Iterable<Class<?>> classes = new Iterable<Class<?>>() {
1162    
1163            @Override
1164            public Iterator<Class<?>> iterator() {
1165                final MutableObject<Class<?>> next = new MutableObject<Class<?>>(type);
1166                return new Iterator<Class<?>>() {
1167    
1168                    @Override
1169                    public boolean hasNext() {
1170                        return next.getValue() != null;
1171                    }
1172    
1173                    @Override
1174                    public Class<?> next() {
1175                        final Class<?> result = next.getValue();
1176                        next.setValue(result.getSuperclass());
1177                        return result;
1178                    }
1179    
1180                    @Override
1181                    public void remove() {
1182                        throw new UnsupportedOperationException();
1183                    }
1184    
1185                };
1186            }
1187    
1188        };
1189        if (interfacesBehavior != Interfaces.INCLUDE) {
1190            return classes;
1191        }
1192        return new Iterable<Class<?>>() {
1193    
1194            @Override
1195            public Iterator<Class<?>> iterator() {
1196                final Set<Class<?>> seenInterfaces = new HashSet<Class<?>>();
1197                final Iterator<Class<?>> wrapped = classes.iterator();
1198    
1199                return new Iterator<Class<?>>() {
1200                    Iterator<Class<?>> interfaces = Collections.<Class<?>> emptySet().iterator();
1201    
1202                    @Override
1203                    public boolean hasNext() {
1204                        return interfaces.hasNext() || wrapped.hasNext();
1205                    }
1206    
1207                    @Override
1208                    public Class<?> next() {
1209                        if (interfaces.hasNext()) {
1210                            final Class<?> nextInterface = interfaces.next();
1211                            seenInterfaces.add(nextInterface);
1212                            return nextInterface;
1213                        }
1214                        final Class<?> nextSuperclass = wrapped.next();
1215                        final Set<Class<?>> currentInterfaces = new LinkedHashSet<Class<?>>();
1216                        walkInterfaces(currentInterfaces, nextSuperclass);
1217                        interfaces = currentInterfaces.iterator();
1218                        return nextSuperclass;
1219                    }
1220    
1221                    private void walkInterfaces(Set<Class<?>> addTo, Class<?> c) {
1222                        for (Class<?> iface : c.getInterfaces()) {
1223                            if (!seenInterfaces.contains(iface)) {
1224                                addTo.add(iface);
1225                            }
1226                            walkInterfaces(addTo, iface);
1227                        }
1228                    }
1229    
1230                    @Override
1231                    public void remove() {
1232                        throw new UnsupportedOperationException();
1233                    }
1234    
1235                };
1236            }
1237        };
1238    }
1239
1240}