1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.lang;
18
19 import java.lang.reflect.Method;
20 import java.lang.reflect.Modifier;
21 import java.util.ArrayList;
22 import java.util.HashMap;
23 import java.util.Iterator;
24 import java.util.List;
25 import java.util.Map;
26
27
28 /**
29 * <p>Operates on classes without using reflection.</p>
30 *
31 * <p>This class handles invalid <code>null</code> inputs as best it can.
32 * Each method documents its behaviour in more detail.</p>
33 *
34 * @author Stephen Colebourne
35 * @author Gary Gregory
36 * @author Norm Deane
37 * @author Alban Peignier
38 * @author Tomasz Blachowicz
39 * @since 2.0
40 * @version $Id: ClassUtils.java 633621 2008-03-04 20:20:23Z mbenson $
41 */
42 public class ClassUtils {
43
44 /**
45 * <p>The package separator character: <code>'.' == {@value}</code>.</p>
46 */
47 public static final char PACKAGE_SEPARATOR_CHAR = '.';
48
49 /**
50 * <p>The package separator String: <code>"."</code>.</p>
51 */
52 public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);
53
54 /**
55 * <p>The inner class separator character: <code>'$' == {@value}</code>.</p>
56 */
57 public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
58
59 /**
60 * <p>The inner class separator String: <code>"$"</code>.</p>
61 */
62 public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
63
64 /**
65 * Maps primitive <code>Class</code>es to their corresponding wrapper <code>Class</code>.
66 */
67 private static Map primitiveWrapperMap = new HashMap();
68 static {
69 primitiveWrapperMap.put(Boolean.TYPE, Boolean.class);
70 primitiveWrapperMap.put(Byte.TYPE, Byte.class);
71 primitiveWrapperMap.put(Character.TYPE, Character.class);
72 primitiveWrapperMap.put(Short.TYPE, Short.class);
73 primitiveWrapperMap.put(Integer.TYPE, Integer.class);
74 primitiveWrapperMap.put(Long.TYPE, Long.class);
75 primitiveWrapperMap.put(Double.TYPE, Double.class);
76 primitiveWrapperMap.put(Float.TYPE, Float.class);
77 primitiveWrapperMap.put(Void.TYPE, Void.TYPE);
78 }
79
80 /**
81 * Maps wrapper <code>Class</code>es to their corresponding primitive types.
82 */
83 private static Map wrapperPrimitiveMap = new HashMap();
84 static {
85 for (Iterator it = primitiveWrapperMap.keySet().iterator(); it.hasNext();) {
86 Class primitiveClass = (Class) it.next();
87 Class wrapperClass = (Class) primitiveWrapperMap.get(primitiveClass);
88 if (!primitiveClass.equals(wrapperClass)) {
89 wrapperPrimitiveMap.put(wrapperClass, primitiveClass);
90 }
91 }
92 }
93
94 /**
95 * Maps a primitive class name to its corresponding abbreviation used in array class names.
96 */
97 private static Map abbreviationMap = new HashMap();
98
99 /**
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 }