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     */
017    package org.apache.commons.lang;
018    
019    import java.lang.reflect.Method;
020    import java.lang.reflect.Modifier;
021    import java.util.ArrayList;
022    import java.util.HashMap;
023    import java.util.Iterator;
024    import java.util.List;
025    import java.util.Map;
026    
027    
028    /**
029     * <p>Operates on classes without using reflection.</p>
030     *
031     * <p>This class handles invalid <code>null</code> inputs as best it can.
032     * Each method documents its behaviour in more detail.</p>
033     *
034     * @author Stephen Colebourne
035     * @author Gary Gregory
036     * @author Norm Deane
037     * @author Alban Peignier
038     * @author Tomasz Blachowicz
039     * @since 2.0
040     * @version $Id: ClassUtils.java 633621 2008-03-04 20:20:23Z mbenson $
041     */
042    public class ClassUtils {
043    
044        /**
045         * <p>The package separator character: <code>'&#x2e;' == {@value}</code>.</p>
046         */
047        public static final char PACKAGE_SEPARATOR_CHAR = '.';
048    
049        /**
050         * <p>The package separator String: <code>"&#x2e;"</code>.</p>
051         */
052        public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);
053    
054        /**
055         * <p>The inner class separator character: <code>'$' == {@value}</code>.</p>
056         */
057        public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
058    
059        /**
060         * <p>The inner class separator String: <code>"$"</code>.</p>
061         */
062        public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
063    
064        /**
065         * Maps primitive <code>Class</code>es to their corresponding wrapper <code>Class</code>.
066         */
067        private static Map primitiveWrapperMap = new HashMap();
068        static {
069             primitiveWrapperMap.put(Boolean.TYPE, Boolean.class);
070             primitiveWrapperMap.put(Byte.TYPE, Byte.class);
071             primitiveWrapperMap.put(Character.TYPE, Character.class);
072             primitiveWrapperMap.put(Short.TYPE, Short.class);
073             primitiveWrapperMap.put(Integer.TYPE, Integer.class);
074             primitiveWrapperMap.put(Long.TYPE, Long.class);
075             primitiveWrapperMap.put(Double.TYPE, Double.class);
076             primitiveWrapperMap.put(Float.TYPE, Float.class);
077             primitiveWrapperMap.put(Void.TYPE, Void.TYPE);
078        }
079    
080        /**
081         * Maps wrapper <code>Class</code>es to their corresponding primitive types.
082         */
083        private static Map wrapperPrimitiveMap = new HashMap();
084        static {
085            for (Iterator it = primitiveWrapperMap.keySet().iterator(); it.hasNext();) {
086                Class primitiveClass = (Class) it.next();
087                Class wrapperClass = (Class) primitiveWrapperMap.get(primitiveClass);
088                if (!primitiveClass.equals(wrapperClass)) {
089                    wrapperPrimitiveMap.put(wrapperClass, primitiveClass);
090                }
091            }
092        }
093    
094        /**
095         * Maps a primitive class name to its corresponding abbreviation used in array class names.
096         */
097        private static Map abbreviationMap = new HashMap();
098    
099        /**
100         * Maps an abbreviation used in array class names to corresponding primitive class name.
101         */
102        private static Map reverseAbbreviationMap = new HashMap();
103        
104        /**
105         * Add primitive type abbreviation to maps of abbreviations.
106         * 
107         * @param primitive Canonical name of primitive type
108         * @param abbreviation Corresponding abbreviation of primitive type
109         */
110        private static void addAbbreviation(String primitive, String abbreviation) {
111            abbreviationMap.put(primitive, abbreviation);
112            reverseAbbreviationMap.put(abbreviation, primitive);
113        }
114        
115        /**
116         * Feed abbreviation maps
117         */
118        static {
119            addAbbreviation("int", "I");
120            addAbbreviation("boolean", "Z");
121            addAbbreviation("float", "F");
122            addAbbreviation("long", "J");
123            addAbbreviation("short", "S");
124            addAbbreviation("byte", "B");
125            addAbbreviation("double", "D");
126            addAbbreviation("char", "C");
127        }
128    
129        /**
130         * <p>ClassUtils instances should NOT be constructed in standard programming.
131         * Instead, the class should be used as
132         * <code>ClassUtils.getShortClassName(cls)</code>.</p>
133         *
134         * <p>This constructor is public to permit tools that require a JavaBean
135         * instance to operate.</p>
136         */
137        public ClassUtils() {
138          super();
139        }
140    
141        // Short class name
142        // ----------------------------------------------------------------------
143        /**
144         * <p>Gets the class name minus the package name for an <code>Object</code>.</p>
145         *
146         * @param object  the class to get the short name for, may be null
147         * @param valueIfNull  the value to return if null
148         * @return the class name of the object without the package name, or the null value
149         */
150        public static String getShortClassName(Object object, String valueIfNull) {
151            if (object == null) {
152                return valueIfNull;
153            }
154            return getShortClassName(object.getClass().getName());
155        }
156    
157        /**
158         * <p>Gets the class name minus the package name from a <code>Class</code>.</p>
159         *
160         * @param cls  the class to get the short name for.
161         * @return the class name without the package name or an empty string
162         */
163        public static String getShortClassName(Class cls) {
164            if (cls == null) {
165                return StringUtils.EMPTY;
166            }
167            return getShortClassName(cls.getName());
168        }
169    
170        /**
171         * <p>Gets the class name minus the package name from a String.</p>
172         *
173         * <p>The string passed in is assumed to be a class name - it is not checked.</p>
174         *
175         * @param className  the className to get the short name for
176         * @return the class name of the class without the package name or an empty string
177         */
178        public static String getShortClassName(String className) {
179            if (className == null) {
180                return StringUtils.EMPTY;
181            }
182            if (className.length() == 0) {
183                return StringUtils.EMPTY;
184            }
185    
186            int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
187            int innerIdx = className.indexOf(
188                    INNER_CLASS_SEPARATOR_CHAR, lastDotIdx == -1 ? 0 : lastDotIdx + 1);
189            String out = className.substring(lastDotIdx + 1);
190            if (innerIdx != -1) {
191                out = out.replace(INNER_CLASS_SEPARATOR_CHAR, PACKAGE_SEPARATOR_CHAR);
192            }
193            return out;
194        }
195    
196        // Package name
197        // ----------------------------------------------------------------------
198        /**
199         * <p>Gets the package name of an <code>Object</code>.</p>
200         *
201         * @param object  the class to get the package name for, may be null
202         * @param valueIfNull  the value to return if null
203         * @return the package name of the object, or the null value
204         */
205        public static String getPackageName(Object object, String valueIfNull) {
206            if (object == null) {
207                return valueIfNull;
208            }
209            return getPackageName(object.getClass().getName());
210        }
211    
212        /**
213         * <p>Gets the package name of a <code>Class</code>.</p>
214         *
215         * @param cls  the class to get the package name for, may be <code>null</code>.
216         * @return the package name or an empty string
217         */
218        public static String getPackageName(Class cls) {
219            if (cls == null) {
220                return StringUtils.EMPTY;
221            }
222            return getPackageName(cls.getName());
223        }
224    
225        /**
226         * <p>Gets the package name from a <code>String</code>.</p>
227         *
228         * <p>The string passed in is assumed to be a class name - it is not checked.</p>
229         * <p>If the class is unpackaged, return an empty string.</p>
230         *
231         * @param className  the className to get the package name for, may be <code>null</code>
232         * @return the package name or an empty string
233         */
234        public static String getPackageName(String className) {
235            if (className == null) {
236                return StringUtils.EMPTY;
237            }
238            int i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
239            if (i == -1) {
240                return StringUtils.EMPTY;
241            }
242            return className.substring(0, i);
243        }
244    
245        // Superclasses/Superinterfaces
246        // ----------------------------------------------------------------------
247        /**
248         * <p>Gets a <code>List</code> of superclasses for the given class.</p>
249         *
250         * @param cls  the class to look up, may be <code>null</code>
251         * @return the <code>List</code> of superclasses in order going up from this one
252         *  <code>null</code> if null input
253         */
254        public static List getAllSuperclasses(Class cls) {
255            if (cls == null) {
256                return null;
257            }
258            List classes = new ArrayList();
259            Class superclass = cls.getSuperclass();
260            while (superclass != null) {
261                classes.add(superclass);
262                superclass = superclass.getSuperclass();
263            }
264            return classes;
265        }
266    
267        /**
268         * <p>Gets a <code>List</code> of all interfaces implemented by the given
269         * class and its superclasses.</p>
270         *
271         * <p>The order is determined by looking through each interface in turn as
272         * declared in the source file and following its hierarchy up. Then each
273         * superclass is considered in the same way. Later duplicates are ignored,
274         * so the order is maintained.</p>
275         *
276         * @param cls  the class to look up, may be <code>null</code>
277         * @return the <code>List</code> of interfaces in order,
278         *  <code>null</code> if null input
279         */
280        public static List getAllInterfaces(Class cls) {
281            if (cls == null) {
282                return null;
283            }
284            List list = new ArrayList();
285            while (cls != null) {
286                Class[] interfaces = cls.getInterfaces();
287                for (int i = 0; i < interfaces.length; i++) {
288                    if (list.contains(interfaces[i]) == false) {
289                        list.add(interfaces[i]);
290                    }
291                    List superInterfaces = getAllInterfaces(interfaces[i]);
292                    for (Iterator it = superInterfaces.iterator(); it.hasNext();) {
293                        Class intface = (Class) it.next();
294                        if (list.contains(intface) == false) {
295                            list.add(intface);
296                        }
297                    }
298                }
299                cls = cls.getSuperclass();
300            }
301            return list;
302        }
303    
304        // Convert list
305        // ----------------------------------------------------------------------
306        /**
307         * <p>Given a <code>List</code> of class names, this method converts them into classes.</p>
308         *
309         * <p>A new <code>List</code> is returned. If the class name cannot be found, <code>null</code>
310         * is stored in the <code>List</code>. If the class name in the <code>List</code> is
311         * <code>null</code>, <code>null</code> is stored in the output <code>List</code>.</p>
312         *
313         * @param classNames  the classNames to change
314         * @return a <code>List</code> of Class objects corresponding to the class names,
315         *  <code>null</code> if null input
316         * @throws ClassCastException if classNames contains a non String entry
317         */
318        public static List convertClassNamesToClasses(List classNames) {
319            if (classNames == null) {
320                return null;
321            }
322            List classes = new ArrayList(classNames.size());
323            for (Iterator it = classNames.iterator(); it.hasNext();) {
324                String className = (String) it.next();
325                try {
326                    classes.add(Class.forName(className));
327                } catch (Exception ex) {
328                    classes.add(null);
329                }
330            }
331            return classes;
332        }
333    
334        /**
335         * <p>Given a <code>List</code> of <code>Class</code> objects, this method converts
336         * them into class names.</p>
337         *
338         * <p>A new <code>List</code> is returned. <code>null</code> objects will be copied into
339         * the returned list as <code>null</code>.</p>
340         *
341         * @param classes  the classes to change
342         * @return a <code>List</code> of class names corresponding to the Class objects,
343         *  <code>null</code> if null input
344         * @throws ClassCastException if <code>classes</code> contains a non-<code>Class</code> entry
345         */
346        public static List convertClassesToClassNames(List classes) {
347            if (classes == null) {
348                return null;
349            }
350            List classNames = new ArrayList(classes.size());
351            for (Iterator it = classes.iterator(); it.hasNext();) {
352                Class cls = (Class) it.next();
353                if (cls == null) {
354                    classNames.add(null);
355                } else {
356                    classNames.add(cls.getName());
357                }
358            }
359            return classNames;
360        }
361    
362        // Is assignable
363        // ----------------------------------------------------------------------
364        /**
365         * <p>Checks if an array of Classes can be assigned to another array of Classes.</p>
366         *
367         * <p>This method calls {@link #isAssignable(Class, Class) isAssignable} for each
368         * Class pair in the input arrays. It can be used to check if a set of arguments
369         * (the first parameter) are suitably compatible with a set of method parameter types
370         * (the second parameter).</p>
371         *
372         * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
373         * method takes into account widenings of primitive classes and
374         * <code>null</code>s.</p>
375         *
376         * <p>Primitive widenings allow an int to be assigned to a <code>long</code>,
377         * <code>float</code> or <code>double</code>. This method returns the correct
378         * result for these cases.</p>
379         *
380         * <p><code>Null</code> may be assigned to any reference type. This method will
381         * return <code>true</code> if <code>null</code> is passed in and the toClass is
382         * non-primitive.</p>
383         *
384         * <p>Specifically, this method tests whether the type represented by the
385         * specified <code>Class</code> parameter can be converted to the type
386         * represented by this <code>Class</code> object via an identity conversion
387         * widening primitive or widening reference conversion. See
388         * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>,
389         * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
390         *
391         * @param classArray  the array of Classes to check, may be <code>null</code>
392         * @param toClassArray  the array of Classes to try to assign into, may be <code>null</code>
393         * @return <code>true</code> if assignment possible
394         */
395        public static boolean isAssignable(Class[] classArray, Class[] toClassArray) {
396            if (ArrayUtils.isSameLength(classArray, toClassArray) == false) {
397                return false;
398            }
399            if (classArray == null) {
400                classArray = ArrayUtils.EMPTY_CLASS_ARRAY;
401            }
402            if (toClassArray == null) {
403                toClassArray = ArrayUtils.EMPTY_CLASS_ARRAY;
404            }
405            for (int i = 0; i < classArray.length; i++) {
406                if (isAssignable(classArray[i], toClassArray[i]) == false) {
407                    return false;
408                }
409            }
410            return true;
411        }
412    
413        /**
414         * <p>Checks if one <code>Class</code> can be assigned to a variable of
415         * another <code>Class</code>.</p>
416         *
417         * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method,
418         * this method takes into account widenings of primitive classes and
419         * <code>null</code>s.</p>
420         *
421         * <p>Primitive widenings allow an int to be assigned to a long, float or
422         * double. This method returns the correct result for these cases.</p>
423         *
424         * <p><code>Null</code> may be assigned to any reference type. This method
425         * will return <code>true</code> if <code>null</code> is passed in and the
426         * toClass is non-primitive.</p>
427         *
428         * <p>Specifically, this method tests whether the type represented by the
429         * specified <code>Class</code> parameter can be converted to the type
430         * represented by this <code>Class</code> object via an identity conversion
431         * widening primitive or widening reference conversion. See
432         * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>,
433         * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
434         *
435         * @param cls  the Class to check, may be null
436         * @param toClass  the Class to try to assign into, returns false if null
437         * @return <code>true</code> if assignment possible
438         */
439        public static boolean isAssignable(Class cls, Class toClass) {
440            if (toClass == null) {
441                return false;
442            }
443            // have to check for null, as isAssignableFrom doesn't
444            if (cls == null) {
445                return !(toClass.isPrimitive());
446            }
447            if (cls.equals(toClass)) {
448                return true;
449            }
450            if (cls.isPrimitive()) {
451                if (toClass.isPrimitive() == false) {
452                    return false;
453                }
454                if (Integer.TYPE.equals(cls)) {
455                    return Long.TYPE.equals(toClass)
456                        || Float.TYPE.equals(toClass)
457                        || Double.TYPE.equals(toClass);
458                }
459                if (Long.TYPE.equals(cls)) {
460                    return Float.TYPE.equals(toClass)
461                        || Double.TYPE.equals(toClass);
462                }
463                if (Boolean.TYPE.equals(cls)) {
464                    return false;
465                }
466                if (Double.TYPE.equals(cls)) {
467                    return false;
468                }
469                if (Float.TYPE.equals(cls)) {
470                    return Double.TYPE.equals(toClass);
471                }
472                if (Character.TYPE.equals(cls)) {
473                    return Integer.TYPE.equals(toClass)
474                        || Long.TYPE.equals(toClass)
475                        || Float.TYPE.equals(toClass)
476                        || Double.TYPE.equals(toClass);
477                }
478                if (Short.TYPE.equals(cls)) {
479                    return Integer.TYPE.equals(toClass)
480                        || Long.TYPE.equals(toClass)
481                        || Float.TYPE.equals(toClass)
482                        || Double.TYPE.equals(toClass);
483                }
484                if (Byte.TYPE.equals(cls)) {
485                    return Short.TYPE.equals(toClass)
486                        || Integer.TYPE.equals(toClass)
487                        || Long.TYPE.equals(toClass)
488                        || Float.TYPE.equals(toClass)
489                        || Double.TYPE.equals(toClass);
490                }
491                // should never get here
492                return false;
493            }
494            return toClass.isAssignableFrom(cls);
495        }
496    
497        /**
498         * <p>Converts the specified primitive Class object to its corresponding
499         * wrapper Class object.</p>
500         *
501         * <p>NOTE: From v2.2, this method handles <code>Void.TYPE</code>,
502         * returning <code>Void.TYPE</code>.</p>
503         *
504         * @param cls  the class to convert, may be null
505         * @return the wrapper class for <code>cls</code> or <code>cls</code> if
506         * <code>cls</code> is not a primitive. <code>null</code> if null input.
507         * @since 2.1
508         */
509        public static Class primitiveToWrapper(Class cls) {
510            Class convertedClass = cls;
511            if (cls != null && cls.isPrimitive()) {
512                convertedClass = (Class) primitiveWrapperMap.get(cls);
513            }
514            return convertedClass;
515        }
516    
517        /**
518         * <p>Converts the specified array of primitive Class objects to an array of
519         * its corresponding wrapper Class objects.</p>
520         *
521         * @param classes  the class array to convert, may be null or empty
522         * @return an array which contains for each given class, the wrapper class or
523         * the original class if class is not a primitive. <code>null</code> if null input.
524         * Empty array if an empty array passed in.
525         * @since 2.1
526         */
527        public static Class[] primitivesToWrappers(Class[] classes) {
528            if (classes == null) {
529                return null;
530            }
531    
532            if (classes.length == 0) {
533                return classes;
534            }
535    
536            Class[] convertedClasses = new Class[classes.length];
537            for (int i=0; i < classes.length; i++) {
538                convertedClasses[i] = primitiveToWrapper( classes[i] );
539            }
540            return convertedClasses;
541        }
542    
543        /**
544         * <p>Converts the specified wrapper class to its corresponding primitive
545         * class.</p>
546         *
547         * <p>This method is the counter part of <code>primitiveToWrapper()</code>.
548         * If the passed in class is a wrapper class for a primitive type, this
549         * primitive type will be returned (e.g. <code>Integer.TYPE</code> for
550         * <code>Integer.class</code>). For other classes, or if the parameter is
551         * <b>null</b>, the return value is <b>null</b>.</p>
552         *
553         * @param cls the class to convert, may be <b>null</b>
554         * @return the corresponding primitive type if <code>cls</code> is a
555         * wrapper class, <b>null</b> otherwise
556         * @see #primitiveToWrapper(Class)
557         * @since 2.4
558         */
559        public static Class wrapperToPrimitive(Class cls) {
560            return (Class) wrapperPrimitiveMap.get(cls);
561        }
562    
563        /**
564         * <p>Converts the specified array of wrapper Class objects to an array of
565         * its corresponding primitive Class objects.</p>
566         *
567         * <p>This method invokes <code>wrapperToPrimitive()</code> for each element
568         * of the passed in array.</p>
569         *
570         * @param classes  the class array to convert, may be null or empty
571         * @return an array which contains for each given class, the primitive class or
572         * <b>null</b> if the original class is not a wrapper class. <code>null</code> if null input.
573         * Empty array if an empty array passed in.
574         * @see #wrapperToPrimitive(Class)
575         * @since 2.4
576         */
577        public static Class[] wrappersToPrimitives(Class[] classes) {        
578            if (classes == null) {
579                return null;
580            }
581    
582            if (classes.length == 0) {
583                return classes;
584            }
585    
586            Class[] convertedClasses = new Class[classes.length];
587            for (int i=0; i < classes.length; i++) {
588                convertedClasses[i] = wrapperToPrimitive( classes[i] );
589            }
590            return convertedClasses;
591        }
592    
593        // Inner class
594        // ----------------------------------------------------------------------
595        /**
596         * <p>Is the specified class an inner class or static nested class.</p>
597         *
598         * @param cls  the class to check, may be null
599         * @return <code>true</code> if the class is an inner or static nested class,
600         *  false if not or <code>null</code>
601         */
602        public static boolean isInnerClass(Class cls) {
603            if (cls == null) {
604                return false;
605            }
606            return cls.getName().indexOf(INNER_CLASS_SEPARATOR_CHAR) >= 0;
607        }
608    
609        // Class loading
610        // ----------------------------------------------------------------------
611        /**
612         * Returns the class represented by <code>className</code> using the
613         * <code>classLoader</code>.  This implementation supports names like
614         * "<code>java.lang.String[]</code>" as well as "<code>[Ljava.lang.String;</code>".
615         *
616         * @param classLoader  the class loader to use to load the class
617         * @param className  the class name
618         * @param initialize  whether the class must be initialized
619         * @return the class represented by <code>className</code> using the <code>classLoader</code>
620         * @throws ClassNotFoundException if the class is not found
621         */
622        public static Class getClass(
623                ClassLoader classLoader, String className, boolean initialize) throws ClassNotFoundException {
624            Class clazz;
625            if (abbreviationMap.containsKey(className)) {
626                String clsName = "[" + abbreviationMap.get(className);
627                clazz = Class.forName(clsName, initialize, classLoader).getComponentType();
628            } else {
629                clazz = Class.forName(toCanonicalName(className), initialize, classLoader);
630            }
631            return clazz;
632        }
633    
634        /**
635         * Returns the (initialized) class represented by <code>className</code>
636         * using the <code>classLoader</code>.  This implementation supports names
637         * like "<code>java.lang.String[]</code>" as well as
638         * "<code>[Ljava.lang.String;</code>".
639         *
640         * @param classLoader  the class loader to use to load the class
641         * @param className  the class name
642         * @return the class represented by <code>className</code> using the <code>classLoader</code>
643         * @throws ClassNotFoundException if the class is not found
644         */
645        public static Class getClass(ClassLoader classLoader, String className) throws ClassNotFoundException {
646            return getClass(classLoader, className, true);
647        }
648    
649        /**
650         * Returns the (initialized )class represented by <code>className</code>
651         * using the current thread's context class loader. This implementation
652         * supports names like "<code>java.lang.String[]</code>" as well as
653         * "<code>[Ljava.lang.String;</code>".
654         *
655         * @param className  the class name
656         * @return the class represented by <code>className</code> using the current thread's context class loader
657         * @throws ClassNotFoundException if the class is not found
658         */
659        public static Class getClass(String className) throws ClassNotFoundException {
660            return getClass(className, true);
661        }
662    
663        /**
664         * Returns the class represented by <code>className</code> using the
665         * current thread's context class loader. This implementation supports
666         * names like "<code>java.lang.String[]</code>" as well as
667         * "<code>[Ljava.lang.String;</code>".
668         *
669         * @param className  the class name
670         * @param initialize  whether the class must be initialized
671         * @return the class represented by <code>className</code> using the current thread's context class loader
672         * @throws ClassNotFoundException if the class is not found
673         */
674        public static Class getClass(String className, boolean initialize) throws ClassNotFoundException {
675            ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
676            ClassLoader loader = contextCL == null ? ClassUtils.class.getClassLoader() : contextCL;
677            return getClass(loader, className, initialize );
678        }
679    
680        // Public method
681        // ----------------------------------------------------------------------
682        /**
683         * <p>Returns the desired Method much like <code>Class.getMethod</code>, however 
684         * it ensures that the returned Method is from a public class or interface and not 
685         * from an anonymous inner class. This means that the Method is invokable and 
686         * doesn't fall foul of Java bug 
687         * <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4071957">4071957</a>).
688         *
689         *  <code><pre>Set set = Collections.unmodifiableSet(...);
690         *  Method method = ClassUtils.getPublicMethod(set.getClass(), "isEmpty",  new Class[0]);
691         *  Object result = method.invoke(set, new Object[]);</pre></code>
692         * </p>
693         *
694         * @param cls  the class to check, not null
695         * @param methodName  the name of the method
696         * @param parameterTypes  the list of parameters
697         * @return the method
698         * @throws NullPointerException if the class is null
699         * @throws SecurityException if a a security violation occured
700         * @throws NoSuchMethodException if the method is not found in the given class
701         *  or if the metothod doen't conform with the requirements
702         */
703        public static Method getPublicMethod(Class cls, String methodName, Class parameterTypes[]) 
704                throws SecurityException, NoSuchMethodException {
705            
706            Method declaredMethod = cls.getMethod(methodName, parameterTypes);
707            if (Modifier.isPublic(declaredMethod.getDeclaringClass().getModifiers())) {
708                return declaredMethod;
709            }
710            
711            List candidateClasses = new ArrayList();
712            candidateClasses.addAll(getAllInterfaces(cls));
713            candidateClasses.addAll(getAllSuperclasses(cls));
714            
715            for (Iterator it = candidateClasses.iterator(); it.hasNext(); ) {
716                Class candidateClass = (Class) it.next();
717                if (!Modifier.isPublic(candidateClass.getModifiers())) {
718                    continue;
719                }
720                Method candidateMethod;
721                try {
722                    candidateMethod = candidateClass.getMethod(methodName, parameterTypes);
723                } catch (NoSuchMethodException ex) {
724                    continue;
725                }
726                if (Modifier.isPublic(candidateMethod.getDeclaringClass().getModifiers())) {
727                    return candidateMethod;
728                }
729            }
730            
731            throw new NoSuchMethodException("Can't find a public method for " +
732                    methodName + " " + ArrayUtils.toString(parameterTypes));
733        }
734    
735        // ----------------------------------------------------------------------
736        /**
737         * Converts a class name to a JLS style class name.
738         *
739         * @param className  the class name
740         * @return the converted name
741         */
742        private static String toCanonicalName(String className) {
743            className = StringUtils.deleteWhitespace(className);
744            if (className == null) {
745                throw new NullArgumentException("className");
746            } else if (className.endsWith("[]")) {
747                StringBuffer classNameBuffer = new StringBuffer();
748                while (className.endsWith("[]")) {
749                    className = className.substring(0, className.length() - 2);
750                    classNameBuffer.append("[");
751                }
752                String abbreviation = (String) abbreviationMap.get(className);
753                if (abbreviation != null) {
754                    classNameBuffer.append(abbreviation);
755                } else {
756                    classNameBuffer.append("L").append(className).append(";");
757                }
758                className = classNameBuffer.toString();
759            }
760            return className;
761        }
762    
763        /**
764         * <p>Converts an array of <code>Object</code> in to an array of <code>Class</code> objects.</p>
765         *
766         * <p>This method returns <code>null</code> for a <code>null</code> input array.</p>
767         *
768         * @param array an <code>Object</code> array
769         * @return a <code>Class</code> array, <code>null</code> if null array input
770         * @since 2.4
771         */
772        public static Class[] toClass(Object[] array)
773        {
774            if (array == null) {
775                return null;
776            } else if (array.length == 0) {
777                return ArrayUtils.EMPTY_CLASS_ARRAY;
778            }
779            Class[] classes = new Class[array.length];
780            for (int i = 0; i < array.length; i++) {
781                classes[i] = array[i].getClass();
782            }
783            return classes;
784        }
785    
786        // Short canonical name
787        // ----------------------------------------------------------------------
788        /**
789         * <p>Gets the canonical name minus the package name for an <code>Object</code>.</p>
790         *
791         * @param object  the class to get the short name for, may be null
792         * @param valueIfNull  the value to return if null
793         * @return the canonical name of the object without the package name, or the null value
794         * @since 2.4
795         */
796        public static String getShortCanonicalName(Object object, String valueIfNull) {
797            if (object == null) {
798                return valueIfNull;
799            }
800            return getShortCanonicalName(object.getClass().getName());
801        }
802    
803        /**
804         * <p>Gets the canonical name minus the package name from a <code>Class</code>.</p>
805         *
806         * @param cls  the class to get the short name for.
807         * @return the canonical name without the package name or an empty string
808         * @since 2.4
809         */
810        public static String getShortCanonicalName(Class cls) {
811            if (cls == null) {
812                return StringUtils.EMPTY;
813            }
814            return getShortCanonicalName(cls.getName());
815        }
816    
817        /**
818         * <p>Gets the canonical name minus the package name from a String.</p>
819         *
820         * <p>The string passed in is assumed to be a canonical name - it is not checked.</p>
821         *
822         * @param canonicalName  the class name to get the short name for
823         * @return the canonical name of the class without the package name or an empty string
824         * @since 2.4
825         */
826        public static String getShortCanonicalName(String canonicalName) {
827            return ClassUtils.getShortClassName(getCanonicalName(canonicalName));
828        }
829    
830        // Package name
831        // ----------------------------------------------------------------------
832        /**
833         * <p>Gets the package name from the canonical name of an <code>Object</code>.</p>
834         *
835         * @param object  the class to get the package name for, may be null
836         * @param valueIfNull  the value to return if null
837         * @return the package name of the object, or the null value
838         * @since 2.4
839         */
840        public static String getPackageCanonicalName(Object object, String valueIfNull) {
841            if (object == null) {
842                return valueIfNull;
843            }
844            return getPackageCanonicalName(object.getClass().getName());
845        }
846    
847        /**
848         * <p>Gets the package name from the canonical name of a <code>Class</code>.</p>
849         *
850         * @param cls  the class to get the package name for, may be <code>null</code>.
851         * @return the package name or an empty string
852         * @since 2.4
853         */
854        public static String getPackageCanonicalName(Class cls) {
855            if (cls == null) {
856                return StringUtils.EMPTY;
857            }
858            return getPackageCanonicalName(cls.getName());
859        }
860    
861        /**
862         * <p>Gets the package name from the canonical name. </p>
863         *
864         * <p>The string passed in is assumed to be a canonical name - it is not checked.</p>
865         * <p>If the class is unpackaged, return an empty string.</p>
866         *
867         * @param canonicalName  the canonical name to get the package name for, may be <code>null</code>
868         * @return the package name or an empty string
869         * @since 2.4
870         */
871        public static String getPackageCanonicalName(String canonicalName) {
872            return ClassUtils.getPackageName(getCanonicalName(canonicalName));
873        }
874    
875        /**
876         * <p>Converts a given name of class into canonical format.
877         * If name of class is not a name of array class it returns
878         * unchanged name.</p>
879         * <p>Example:
880         * <ul>
881         * <li><code>getCanonicalName("[I") = "int[]"</code></li>
882         * <li><code>getCanonicalName("[Ljava.lang.String;") = "java.lang.String[]"</code></li>
883         * <li><code>getCanonicalName("java.lang.String") = "java.lang.String"</code></li>
884         * </ul>
885         * </p>
886         * 
887         * @param className the name of class
888         * @return canonical form of class name
889         * @since 2.4
890         */
891        private static String getCanonicalName(String className) {
892            className = StringUtils.deleteWhitespace(className);
893            if (className == null) {
894                return null;
895            } else {
896                int dim = 0;
897                while(className.startsWith("[")) {
898                    dim++;
899                    className = className.substring(1);
900                }
901                if(dim < 1) {
902                    return className;
903                } else {
904                    if(className.startsWith("L")) {
905                        className = className.substring(
906                            1,
907                            className.endsWith(";")
908                                ? className.length() - 1
909                                : className.length());
910                    } else {
911                        if(className.length() > 0) {
912                            className = (String) reverseAbbreviationMap.get(
913                                className.substring(0, 1));
914                        }
915                    }
916                    StringBuffer canonicalClassNameBuffer = new StringBuffer(className);
917                    for(int i = 0; i < dim; i++) {
918                        canonicalClassNameBuffer.append("[]");
919                    }
920                    return canonicalClassNameBuffer.toString();
921                }
922            }
923        }
924    }