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.lang3;
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.HashSet;
024 import java.util.LinkedHashSet;
025 import java.util.List;
026 import java.util.Map;
027
028
029 /**
030 * <p>Operates on classes without using reflection.</p>
031 *
032 * <p>This class handles invalid {@code null} inputs as best it can.
033 * Each method documents its behaviour in more detail.</p>
034 *
035 * <p>The notion of a {@code canonical name} includes the human
036 * readable name for the type, for example {@code int[]}. The
037 * non-canonical method variants work with the JVM names, such as
038 * {@code [I}. </p>
039 *
040 * @since 2.0
041 * @version $Id: ClassUtils.java 1145035 2011-07-11 06:09:39Z bayard $
042 */
043 public class ClassUtils {
044
045 /**
046 * <p>The package separator character: <code>'.' == {@value}</code>.</p>
047 */
048 public static final char PACKAGE_SEPARATOR_CHAR = '.';
049
050 /**
051 * <p>The package separator String: {@code "."}.</p>
052 */
053 public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);
054
055 /**
056 * <p>The inner class separator character: <code>'$' == {@value}</code>.</p>
057 */
058 public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
059
060 /**
061 * <p>The inner class separator String: {@code "$"}.</p>
062 */
063 public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
064
065 /**
066 * Maps primitive {@code Class}es to their corresponding wrapper {@code Class}.
067 */
068 private static final Map<Class<?>, Class<?>> primitiveWrapperMap = new HashMap<Class<?>, Class<?>>();
069 static {
070 primitiveWrapperMap.put(Boolean.TYPE, Boolean.class);
071 primitiveWrapperMap.put(Byte.TYPE, Byte.class);
072 primitiveWrapperMap.put(Character.TYPE, Character.class);
073 primitiveWrapperMap.put(Short.TYPE, Short.class);
074 primitiveWrapperMap.put(Integer.TYPE, Integer.class);
075 primitiveWrapperMap.put(Long.TYPE, Long.class);
076 primitiveWrapperMap.put(Double.TYPE, Double.class);
077 primitiveWrapperMap.put(Float.TYPE, Float.class);
078 primitiveWrapperMap.put(Void.TYPE, Void.TYPE);
079 }
080
081 /**
082 * Maps wrapper {@code Class}es to their corresponding primitive types.
083 */
084 private static final Map<Class<?>, Class<?>> wrapperPrimitiveMap = new HashMap<Class<?>, Class<?>>();
085 static {
086 for (Class<?> primitiveClass : primitiveWrapperMap.keySet()) {
087 Class<?> wrapperClass = 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 final Map<String, String> abbreviationMap = new HashMap<String, String>();
098
099 /**
100 * Maps an abbreviation used in array class names to corresponding primitive class name.
101 */
102 private static final Map<String, String> reverseAbbreviationMap = new HashMap<String, String>();
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)}.</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}.</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());
155 }
156
157 /**
158 * <p>Gets the class name minus the package name from a {@code Class}.</p>
159 *
160 * <p>Consider using the Java 5 API {@link Class#getSimpleName()} instead.
161 * The one known difference is that this code will return {@code "Map.Entry"} while
162 * the {@code java.lang.Class} variant will simply return {@code "Entry"}. </p>
163 *
164 * @param cls the class to get the short name for.
165 * @return the class name without the package name or an empty string
166 */
167 public static String getShortClassName(Class<?> cls) {
168 if (cls == null) {
169 return StringUtils.EMPTY;
170 }
171 return getShortClassName(cls.getName());
172 }
173
174 /**
175 * <p>Gets the class name minus the package name from a String.</p>
176 *
177 * <p>The string passed in is assumed to be a class name - it is not checked.</p>
178
179 * <p>Note that this method differs from Class.getSimpleName() in that this will
180 * return {@code "Map.Entry"} whilst the {@code java.lang.Class} variant will simply
181 * return {@code "Entry"}. </p>
182 *
183 * @param className the className to get the short name for
184 * @return the class name of the class without the package name or an empty string
185 */
186 public static String getShortClassName(String className) {
187 if (className == null) {
188 return StringUtils.EMPTY;
189 }
190 if (className.length() == 0) {
191 return StringUtils.EMPTY;
192 }
193
194 StringBuilder arrayPrefix = new StringBuilder();
195
196 // Handle array encoding
197 if (className.startsWith("[")) {
198 while (className.charAt(0) == '[') {
199 className = className.substring(1);
200 arrayPrefix.append("[]");
201 }
202 // Strip Object type encoding
203 if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
204 className = className.substring(1, className.length() - 1);
205 }
206 }
207
208 if (reverseAbbreviationMap.containsKey(className)) {
209 className = reverseAbbreviationMap.get(className);
210 }
211
212 int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
213 int innerIdx = className.indexOf(
214 INNER_CLASS_SEPARATOR_CHAR, lastDotIdx == -1 ? 0 : lastDotIdx + 1);
215 String out = className.substring(lastDotIdx + 1);
216 if (innerIdx != -1) {
217 out = out.replace(INNER_CLASS_SEPARATOR_CHAR, PACKAGE_SEPARATOR_CHAR);
218 }
219 return out + arrayPrefix;
220 }
221
222 /**
223 * <p>Null-safe version of <code>aClass.getSimpleName()</code></p>
224 *
225 * @param cls the class for which to get the simple name.
226 * @return the simple class name.
227 * @since 3.0
228 * @see Class#getSimpleName()
229 */
230 public static String getSimpleName(Class<?> cls) {
231 if (cls == null) {
232 return StringUtils.EMPTY;
233 }
234 return cls.getSimpleName();
235 }
236
237 /**
238 * <p>Null-safe version of <code>aClass.getSimpleName()</code></p>
239 *
240 * @param object the object for which to get the simple class name.
241 * @param valueIfNull the value to return if <code>object</code> is <code>null</code>
242 * @return the simple class name.
243 * @since 3.0
244 * @see Class#getSimpleName()
245 */
246 public static String getSimpleName(Object object, String valueIfNull) {
247 if (object == null) {
248 return valueIfNull;
249 }
250 return getSimpleName(object.getClass());
251 }
252
253 // Package name
254 // ----------------------------------------------------------------------
255 /**
256 * <p>Gets the package name of an {@code Object}.</p>
257 *
258 * @param object the class to get the package name for, may be null
259 * @param valueIfNull the value to return if null
260 * @return the package name of the object, or the null value
261 */
262 public static String getPackageName(Object object, String valueIfNull) {
263 if (object == null) {
264 return valueIfNull;
265 }
266 return getPackageName(object.getClass());
267 }
268
269 /**
270 * <p>Gets the package name of a {@code Class}.</p>
271 *
272 * @param cls the class to get the package name for, may be {@code null}.
273 * @return the package name or an empty string
274 */
275 public static String getPackageName(Class<?> cls) {
276 if (cls == null) {
277 return StringUtils.EMPTY;
278 }
279 return getPackageName(cls.getName());
280 }
281
282 /**
283 * <p>Gets the package name from a {@code String}.</p>
284 *
285 * <p>The string passed in is assumed to be a class name - it is not checked.</p>
286 * <p>If the class is unpackaged, return an empty string.</p>
287 *
288 * @param className the className to get the package name for, may be {@code null}
289 * @return the package name or an empty string
290 */
291 public static String getPackageName(String className) {
292 if (className == null || className.length() == 0) {
293 return StringUtils.EMPTY;
294 }
295
296 // Strip array encoding
297 while (className.charAt(0) == '[') {
298 className = className.substring(1);
299 }
300 // Strip Object type encoding
301 if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
302 className = className.substring(1);
303 }
304
305 int i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
306 if (i == -1) {
307 return StringUtils.EMPTY;
308 }
309 return className.substring(0, i);
310 }
311
312 // Superclasses/Superinterfaces
313 // ----------------------------------------------------------------------
314 /**
315 * <p>Gets a {@code List} of superclasses for the given class.</p>
316 *
317 * @param cls the class to look up, may be {@code null}
318 * @return the {@code List} of superclasses in order going up from this one
319 * {@code null} if null input
320 */
321 public static List<Class<?>> getAllSuperclasses(Class<?> cls) {
322 if (cls == null) {
323 return null;
324 }
325 List<Class<?>> classes = new ArrayList<Class<?>>();
326 Class<?> superclass = cls.getSuperclass();
327 while (superclass != null) {
328 classes.add(superclass);
329 superclass = superclass.getSuperclass();
330 }
331 return classes;
332 }
333
334 /**
335 * <p>Gets a {@code List} of all interfaces implemented by the given
336 * class and its superclasses.</p>
337 *
338 * <p>The order is determined by looking through each interface in turn as
339 * declared in the source file and following its hierarchy up. Then each
340 * superclass is considered in the same way. Later duplicates are ignored,
341 * so the order is maintained.</p>
342 *
343 * @param cls the class to look up, may be {@code null}
344 * @return the {@code List} of interfaces in order,
345 * {@code null} if null input
346 */
347 public static List<Class<?>> getAllInterfaces(Class<?> cls) {
348 if (cls == null) {
349 return null;
350 }
351
352 LinkedHashSet<Class<?>> interfacesFound = new LinkedHashSet<Class<?>>();
353 getAllInterfaces(cls, interfacesFound);
354
355 return new ArrayList<Class<?>>(interfacesFound);
356 }
357
358 /**
359 * Get the interfaces for the specified class.
360 *
361 * @param cls the class to look up, may be {@code null}
362 * @param interfacesFound the {@code Set} of interfaces for the class
363 */
364 private static void getAllInterfaces(Class<?> cls, HashSet<Class<?>> interfacesFound) {
365 while (cls != null) {
366 Class<?>[] interfaces = cls.getInterfaces();
367
368 for (Class<?> i : interfaces) {
369 if (interfacesFound.add(i)) {
370 getAllInterfaces(i, interfacesFound);
371 }
372 }
373
374 cls = cls.getSuperclass();
375 }
376 }
377
378 // Convert list
379 // ----------------------------------------------------------------------
380 /**
381 * <p>Given a {@code List} of class names, this method converts them into classes.</p>
382 *
383 * <p>A new {@code List} is returned. If the class name cannot be found, {@code null}
384 * is stored in the {@code List}. If the class name in the {@code List} is
385 * {@code null}, {@code null} is stored in the output {@code List}.</p>
386 *
387 * @param classNames the classNames to change
388 * @return a {@code List} of Class objects corresponding to the class names,
389 * {@code null} if null input
390 * @throws ClassCastException if classNames contains a non String entry
391 */
392 public static List<Class<?>> convertClassNamesToClasses(List<String> classNames) {
393 if (classNames == null) {
394 return null;
395 }
396 List<Class<?>> classes = new ArrayList<Class<?>>(classNames.size());
397 for (String className : classNames) {
398 try {
399 classes.add(Class.forName(className));
400 } catch (Exception ex) {
401 classes.add(null);
402 }
403 }
404 return classes;
405 }
406
407 /**
408 * <p>Given a {@code List} of {@code Class} objects, this method converts
409 * them into class names.</p>
410 *
411 * <p>A new {@code List} is returned. {@code null} objects will be copied into
412 * the returned list as {@code null}.</p>
413 *
414 * @param classes the classes to change
415 * @return a {@code List} of class names corresponding to the Class objects,
416 * {@code null} if null input
417 * @throws ClassCastException if {@code classes} contains a non-{@code Class} entry
418 */
419 public static List<String> convertClassesToClassNames(List<Class<?>> classes) {
420 if (classes == null) {
421 return null;
422 }
423 List<String> classNames = new ArrayList<String>(classes.size());
424 for (Class<?> cls : classes) {
425 if (cls == null) {
426 classNames.add(null);
427 } else {
428 classNames.add(cls.getName());
429 }
430 }
431 return classNames;
432 }
433
434 // Is assignable
435 // ----------------------------------------------------------------------
436 /**
437 * <p>Checks if an array of Classes can be assigned to another array of Classes.</p>
438 *
439 * <p>This method calls {@link #isAssignable(Class, Class) isAssignable} for each
440 * Class pair in the input arrays. It can be used to check if a set of arguments
441 * (the first parameter) are suitably compatible with a set of method parameter types
442 * (the second parameter).</p>
443 *
444 * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
445 * method takes into account widenings of primitive classes and
446 * {@code null}s.</p>
447 *
448 * <p>Primitive widenings allow an int to be assigned to a {@code long},
449 * {@code float} or {@code double}. This method returns the correct
450 * result for these cases.</p>
451 *
452 * <p>{@code Null} may be assigned to any reference type. This method will
453 * return {@code true} if {@code null} is passed in and the toClass is
454 * non-primitive.</p>
455 *
456 * <p>Specifically, this method tests whether the type represented by the
457 * specified {@code Class} parameter can be converted to the type
458 * represented by this {@code Class} object via an identity conversion
459 * widening primitive or widening reference conversion. See
460 * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>,
461 * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
462 *
463 * <p><strong>Since Lang 3.0,</strong> this method will default behavior for
464 * calculating assignability between primitive and wrapper types <em>corresponding
465 * to the running Java version</em>; i.e. autoboxing will be the default
466 * behavior in VMs running Java versions >= 1.5.</p>
467 *
468 * @param classArray the array of Classes to check, may be {@code null}
469 * @param toClassArray the array of Classes to try to assign into, may be {@code null}
470 * @return {@code true} if assignment possible
471 */
472 public static boolean isAssignable(Class<?>[] classArray, Class<?>... toClassArray) {
473 return isAssignable(classArray, toClassArray, SystemUtils.isJavaVersionAtLeast(JavaVersion.JAVA_1_5));
474 }
475
476 /**
477 * <p>Checks if an array of Classes can be assigned to another array of Classes.</p>
478 *
479 * <p>This method calls {@link #isAssignable(Class, Class) isAssignable} for each
480 * Class pair in the input arrays. It can be used to check if a set of arguments
481 * (the first parameter) are suitably compatible with a set of method parameter types
482 * (the second parameter).</p>
483 *
484 * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
485 * method takes into account widenings of primitive classes and
486 * {@code null}s.</p>
487 *
488 * <p>Primitive widenings allow an int to be assigned to a {@code long},
489 * {@code float} or {@code double}. This method returns the correct
490 * result for these cases.</p>
491 *
492 * <p>{@code Null} may be assigned to any reference type. This method will
493 * return {@code true} if {@code null} is passed in and the toClass is
494 * non-primitive.</p>
495 *
496 * <p>Specifically, this method tests whether the type represented by the
497 * specified {@code Class} parameter can be converted to the type
498 * represented by this {@code Class} object via an identity conversion
499 * widening primitive or widening reference conversion. See
500 * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>,
501 * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
502 *
503 * @param classArray the array of Classes to check, may be {@code null}
504 * @param toClassArray the array of Classes to try to assign into, may be {@code null}
505 * @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers
506 * @return {@code true} if assignment possible
507 */
508 public static boolean isAssignable(Class<?>[] classArray, Class<?>[] toClassArray, boolean autoboxing) {
509 if (ArrayUtils.isSameLength(classArray, toClassArray) == false) {
510 return false;
511 }
512 if (classArray == null) {
513 classArray = ArrayUtils.EMPTY_CLASS_ARRAY;
514 }
515 if (toClassArray == null) {
516 toClassArray = ArrayUtils.EMPTY_CLASS_ARRAY;
517 }
518 for (int i = 0; i < classArray.length; i++) {
519 if (isAssignable(classArray[i], toClassArray[i], autoboxing) == false) {
520 return false;
521 }
522 }
523 return true;
524 }
525
526 /**
527 * <p>Checks if one {@code Class} can be assigned to a variable of
528 * another {@code Class}.</p>
529 *
530 * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method,
531 * this method takes into account widenings of primitive classes and
532 * {@code null}s.</p>
533 *
534 * <p>Primitive widenings allow an int to be assigned to a long, float or
535 * double. This method returns the correct result for these cases.</p>
536 *
537 * <p>{@code Null} may be assigned to any reference type. This method
538 * will return {@code true} if {@code null} is passed in and the
539 * toClass is non-primitive.</p>
540 *
541 * <p>Specifically, this method tests whether the type represented by the
542 * specified {@code Class} parameter can be converted to the type
543 * represented by this {@code Class} object via an identity conversion
544 * widening primitive or widening reference conversion. See
545 * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>,
546 * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
547 *
548 * <p><strong>Since Lang 3.0,</strong> this method will default behavior for
549 * calculating assignability between primitive and wrapper types <em>corresponding
550 * to the running Java version</em>; i.e. autoboxing will be the default
551 * behavior in VMs running Java versions >= 1.5.</p>
552 *
553 * @param cls the Class to check, may be null
554 * @param toClass the Class to try to assign into, returns false if null
555 * @return {@code true} if assignment possible
556 */
557 public static boolean isAssignable(Class<?> cls, Class<?> toClass) {
558 return isAssignable(cls, toClass, SystemUtils.isJavaVersionAtLeast(JavaVersion.JAVA_1_5));
559 }
560
561 /**
562 * <p>Checks if one {@code Class} can be assigned to a variable of
563 * another {@code Class}.</p>
564 *
565 * <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method,
566 * this method takes into account widenings of primitive classes and
567 * {@code null}s.</p>
568 *
569 * <p>Primitive widenings allow an int to be assigned to a long, float or
570 * double. This method returns the correct result for these cases.</p>
571 *
572 * <p>{@code Null} may be assigned to any reference type. This method
573 * will return {@code true} if {@code null} is passed in and the
574 * toClass is non-primitive.</p>
575 *
576 * <p>Specifically, this method tests whether the type represented by the
577 * specified {@code Class} parameter can be converted to the type
578 * represented by this {@code Class} object via an identity conversion
579 * widening primitive or widening reference conversion. See
580 * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>,
581 * sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
582 *
583 * @param cls the Class to check, may be null
584 * @param toClass the Class to try to assign into, returns false if null
585 * @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers
586 * @return {@code true} if assignment possible
587 */
588 public static boolean isAssignable(Class<?> cls, Class<?> toClass, boolean autoboxing) {
589 if (toClass == null) {
590 return false;
591 }
592 // have to check for null, as isAssignableFrom doesn't
593 if (cls == null) {
594 return !(toClass.isPrimitive());
595 }
596 //autoboxing:
597 if (autoboxing) {
598 if (cls.isPrimitive() && !toClass.isPrimitive()) {
599 cls = primitiveToWrapper(cls);
600 if (cls == null) {
601 return false;
602 }
603 }
604 if (toClass.isPrimitive() && !cls.isPrimitive()) {
605 cls = wrapperToPrimitive(cls);
606 if (cls == null) {
607 return false;
608 }
609 }
610 }
611 if (cls.equals(toClass)) {
612 return true;
613 }
614 if (cls.isPrimitive()) {
615 if (toClass.isPrimitive() == false) {
616 return false;
617 }
618 if (Integer.TYPE.equals(cls)) {
619 return Long.TYPE.equals(toClass)
620 || Float.TYPE.equals(toClass)
621 || Double.TYPE.equals(toClass);
622 }
623 if (Long.TYPE.equals(cls)) {
624 return Float.TYPE.equals(toClass)
625 || Double.TYPE.equals(toClass);
626 }
627 if (Boolean.TYPE.equals(cls)) {
628 return false;
629 }
630 if (Double.TYPE.equals(cls)) {
631 return false;
632 }
633 if (Float.TYPE.equals(cls)) {
634 return Double.TYPE.equals(toClass);
635 }
636 if (Character.TYPE.equals(cls)) {
637 return Integer.TYPE.equals(toClass)
638 || Long.TYPE.equals(toClass)
639 || Float.TYPE.equals(toClass)
640 || Double.TYPE.equals(toClass);
641 }
642 if (Short.TYPE.equals(cls)) {
643 return Integer.TYPE.equals(toClass)
644 || Long.TYPE.equals(toClass)
645 || Float.TYPE.equals(toClass)
646 || Double.TYPE.equals(toClass);
647 }
648 if (Byte.TYPE.equals(cls)) {
649 return Short.TYPE.equals(toClass)
650 || Integer.TYPE.equals(toClass)
651 || Long.TYPE.equals(toClass)
652 || Float.TYPE.equals(toClass)
653 || Double.TYPE.equals(toClass);
654 }
655 // should never get here
656 return false;
657 }
658 return toClass.isAssignableFrom(cls);
659 }
660
661 /**
662 * <p>Converts the specified primitive Class object to its corresponding
663 * wrapper Class object.</p>
664 *
665 * <p>NOTE: From v2.2, this method handles {@code Void.TYPE},
666 * returning {@code Void.TYPE}.</p>
667 *
668 * @param cls the class to convert, may be null
669 * @return the wrapper class for {@code cls} or {@code cls} if
670 * {@code cls} is not a primitive. {@code null} if null input.
671 * @since 2.1
672 */
673 public static Class<?> primitiveToWrapper(Class<?> cls) {
674 Class<?> convertedClass = cls;
675 if (cls != null && cls.isPrimitive()) {
676 convertedClass = primitiveWrapperMap.get(cls);
677 }
678 return convertedClass;
679 }
680
681 /**
682 * <p>Converts the specified array of primitive Class objects to an array of
683 * its corresponding wrapper Class objects.</p>
684 *
685 * @param classes the class array to convert, may be null or empty
686 * @return an array which contains for each given class, the wrapper class or
687 * the original class if class is not a primitive. {@code null} if null input.
688 * Empty array if an empty array passed in.
689 * @since 2.1
690 */
691 public static Class<?>[] primitivesToWrappers(Class<?>... classes) {
692 if (classes == null) {
693 return null;
694 }
695
696 if (classes.length == 0) {
697 return classes;
698 }
699
700 Class<?>[] convertedClasses = new Class[classes.length];
701 for (int i = 0; i < classes.length; i++) {
702 convertedClasses[i] = primitiveToWrapper(classes[i]);
703 }
704 return convertedClasses;
705 }
706
707 /**
708 * <p>Converts the specified wrapper class to its corresponding primitive
709 * class.</p>
710 *
711 * <p>This method is the counter part of {@code primitiveToWrapper()}.
712 * If the passed in class is a wrapper class for a primitive type, this
713 * primitive type will be returned (e.g. {@code Integer.TYPE} for
714 * {@code Integer.class}). For other classes, or if the parameter is
715 * <b>null</b>, the return value is <b>null</b>.</p>
716 *
717 * @param cls the class to convert, may be <b>null</b>
718 * @return the corresponding primitive type if {@code cls} is a
719 * wrapper class, <b>null</b> otherwise
720 * @see #primitiveToWrapper(Class)
721 * @since 2.4
722 */
723 public static Class<?> wrapperToPrimitive(Class<?> cls) {
724 return wrapperPrimitiveMap.get(cls);
725 }
726
727 /**
728 * <p>Converts the specified array of wrapper Class objects to an array of
729 * its corresponding primitive Class objects.</p>
730 *
731 * <p>This method invokes {@code wrapperToPrimitive()} for each element
732 * of the passed in array.</p>
733 *
734 * @param classes the class array to convert, may be null or empty
735 * @return an array which contains for each given class, the primitive class or
736 * <b>null</b> if the original class is not a wrapper class. {@code null} if null input.
737 * Empty array if an empty array passed in.
738 * @see #wrapperToPrimitive(Class)
739 * @since 2.4
740 */
741 public static Class<?>[] wrappersToPrimitives(Class<?>... classes) {
742 if (classes == null) {
743 return null;
744 }
745
746 if (classes.length == 0) {
747 return classes;
748 }
749
750 Class<?>[] convertedClasses = new Class[classes.length];
751 for (int i = 0; i < classes.length; i++) {
752 convertedClasses[i] = wrapperToPrimitive(classes[i]);
753 }
754 return convertedClasses;
755 }
756
757 // Inner class
758 // ----------------------------------------------------------------------
759 /**
760 * <p>Is the specified class an inner class or static nested class.</p>
761 *
762 * @param cls the class to check, may be null
763 * @return {@code true} if the class is an inner or static nested class,
764 * false if not or {@code null}
765 */
766 public static boolean isInnerClass(Class<?> cls) {
767 return cls != null && cls.getEnclosingClass() != null;
768 }
769
770 // Class loading
771 // ----------------------------------------------------------------------
772 /**
773 * Returns the class represented by {@code className} using the
774 * {@code classLoader}. This implementation supports the syntaxes
775 * "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
776 * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
777 *
778 * @param classLoader the class loader to use to load the class
779 * @param className the class name
780 * @param initialize whether the class must be initialized
781 * @return the class represented by {@code className} using the {@code classLoader}
782 * @throws ClassNotFoundException if the class is not found
783 */
784 public static Class<?> getClass(
785 ClassLoader classLoader, String className, boolean initialize) throws ClassNotFoundException {
786 try {
787 Class<?> clazz;
788 if (abbreviationMap.containsKey(className)) {
789 String clsName = "[" + abbreviationMap.get(className);
790 clazz = Class.forName(clsName, initialize, classLoader).getComponentType();
791 } else {
792 clazz = Class.forName(toCanonicalName(className), initialize, classLoader);
793 }
794 return clazz;
795 } catch (ClassNotFoundException ex) {
796 // allow path separators (.) as inner class name separators
797 int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
798
799 if (lastDotIndex != -1) {
800 try {
801 return getClass(classLoader, className.substring(0, lastDotIndex) +
802 INNER_CLASS_SEPARATOR_CHAR + className.substring(lastDotIndex + 1),
803 initialize);
804 } catch (ClassNotFoundException ex2) { // NOPMD
805 // ignore exception
806 }
807 }
808
809 throw ex;
810 }
811 }
812
813 /**
814 * Returns the (initialized) class represented by {@code className}
815 * using the {@code classLoader}. This implementation supports
816 * the syntaxes "{@code java.util.Map.Entry[]}",
817 * "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}",
818 * and "{@code [Ljava.util.Map$Entry;}".
819 *
820 * @param classLoader the class loader to use to load the class
821 * @param className the class name
822 * @return the class represented by {@code className} using the {@code classLoader}
823 * @throws ClassNotFoundException if the class is not found
824 */
825 public static Class<?> getClass(ClassLoader classLoader, String className) throws ClassNotFoundException {
826 return getClass(classLoader, className, true);
827 }
828
829 /**
830 * Returns the (initialized) class represented by {@code className}
831 * using the current thread's context class loader. This implementation
832 * supports the syntaxes "{@code java.util.Map.Entry[]}",
833 * "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}",
834 * and "{@code [Ljava.util.Map$Entry;}".
835 *
836 * @param className the class name
837 * @return the class represented by {@code className} using the current thread's context class loader
838 * @throws ClassNotFoundException if the class is not found
839 */
840 public static Class<?> getClass(String className) throws ClassNotFoundException {
841 return getClass(className, true);
842 }
843
844 /**
845 * Returns the class represented by {@code className} using the
846 * current thread's context class loader. This implementation supports the
847 * syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
848 * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
849 *
850 * @param className the class name
851 * @param initialize whether the class must be initialized
852 * @return the class represented by {@code className} using the current thread's context class loader
853 * @throws ClassNotFoundException if the class is not found
854 */
855 public static Class<?> getClass(String className, boolean initialize) throws ClassNotFoundException {
856 ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
857 ClassLoader loader = contextCL == null ? ClassUtils.class.getClassLoader() : contextCL;
858 return getClass(loader, className, initialize );
859 }
860
861 // Public method
862 // ----------------------------------------------------------------------
863 /**
864 * <p>Returns the desired Method much like {@code Class.getMethod}, however
865 * it ensures that the returned Method is from a public class or interface and not
866 * from an anonymous inner class. This means that the Method is invokable and
867 * doesn't fall foul of Java bug
868 * <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4071957">4071957</a>).
869 *
870 * <code><pre>Set set = Collections.unmodifiableSet(...);
871 * Method method = ClassUtils.getPublicMethod(set.getClass(), "isEmpty", new Class[0]);
872 * Object result = method.invoke(set, new Object[]);</pre></code>
873 * </p>
874 *
875 * @param cls the class to check, not null
876 * @param methodName the name of the method
877 * @param parameterTypes the list of parameters
878 * @return the method
879 * @throws NullPointerException if the class is null
880 * @throws SecurityException if a a security violation occured
881 * @throws NoSuchMethodException if the method is not found in the given class
882 * or if the metothod doen't conform with the requirements
883 */
884 public static Method getPublicMethod(Class<?> cls, String methodName, Class<?>... parameterTypes)
885 throws SecurityException, NoSuchMethodException {
886
887 Method declaredMethod = cls.getMethod(methodName, parameterTypes);
888 if (Modifier.isPublic(declaredMethod.getDeclaringClass().getModifiers())) {
889 return declaredMethod;
890 }
891
892 List<Class<?>> candidateClasses = new ArrayList<Class<?>>();
893 candidateClasses.addAll(getAllInterfaces(cls));
894 candidateClasses.addAll(getAllSuperclasses(cls));
895
896 for (Class<?> candidateClass : candidateClasses) {
897 if (!Modifier.isPublic(candidateClass.getModifiers())) {
898 continue;
899 }
900 Method candidateMethod;
901 try {
902 candidateMethod = candidateClass.getMethod(methodName, parameterTypes);
903 } catch (NoSuchMethodException ex) {
904 continue;
905 }
906 if (Modifier.isPublic(candidateMethod.getDeclaringClass().getModifiers())) {
907 return candidateMethod;
908 }
909 }
910
911 throw new NoSuchMethodException("Can't find a public method for " +
912 methodName + " " + ArrayUtils.toString(parameterTypes));
913 }
914
915 // ----------------------------------------------------------------------
916 /**
917 * Converts a class name to a JLS style class name.
918 *
919 * @param className the class name
920 * @return the converted name
921 */
922 private static String toCanonicalName(String className) {
923 className = StringUtils.deleteWhitespace(className);
924 if (className == null) {
925 throw new NullPointerException("className must not be null.");
926 } else if (className.endsWith("[]")) {
927 StringBuilder classNameBuffer = new StringBuilder();
928 while (className.endsWith("[]")) {
929 className = className.substring(0, className.length() - 2);
930 classNameBuffer.append("[");
931 }
932 String abbreviation = abbreviationMap.get(className);
933 if (abbreviation != null) {
934 classNameBuffer.append(abbreviation);
935 } else {
936 classNameBuffer.append("L").append(className).append(";");
937 }
938 className = classNameBuffer.toString();
939 }
940 return className;
941 }
942
943 /**
944 * <p>Converts an array of {@code Object} in to an array of {@code Class} objects.
945 * If any of these objects is null, a null element will be inserted into the array.</p>
946 *
947 * <p>This method returns {@code null} for a {@code null} input array.</p>
948 *
949 * @param array an {@code Object} array
950 * @return a {@code Class} array, {@code null} if null array input
951 * @since 2.4
952 */
953 public static Class<?>[] toClass(Object... array) {
954 if (array == null) {
955 return null;
956 } else if (array.length == 0) {
957 return ArrayUtils.EMPTY_CLASS_ARRAY;
958 }
959 Class<?>[] classes = new Class[array.length];
960 for (int i = 0; i < array.length; i++) {
961 classes[i] = array[i] == null ? null : array[i].getClass();
962 }
963 return classes;
964 }
965
966 // Short canonical name
967 // ----------------------------------------------------------------------
968 /**
969 * <p>Gets the canonical name minus the package name for an {@code Object}.</p>
970 *
971 * @param object the class to get the short name for, may be null
972 * @param valueIfNull the value to return if null
973 * @return the canonical name of the object without the package name, or the null value
974 * @since 2.4
975 */
976 public static String getShortCanonicalName(Object object, String valueIfNull) {
977 if (object == null) {
978 return valueIfNull;
979 }
980 return getShortCanonicalName(object.getClass().getName());
981 }
982
983 /**
984 * <p>Gets the canonical name minus the package name from a {@code Class}.</p>
985 *
986 * @param cls the class to get the short name for.
987 * @return the canonical name without the package name or an empty string
988 * @since 2.4
989 */
990 public static String getShortCanonicalName(Class<?> cls) {
991 if (cls == null) {
992 return StringUtils.EMPTY;
993 }
994 return getShortCanonicalName(cls.getName());
995 }
996
997 /**
998 * <p>Gets the canonical name minus the package name from a String.</p>
999 *
1000 * <p>The string passed in is assumed to be a canonical name - it is not checked.</p>
1001 *
1002 * @param canonicalName the class name to get the short name for
1003 * @return the canonical name of the class without the package name or an empty string
1004 * @since 2.4
1005 */
1006 public static String getShortCanonicalName(String canonicalName) {
1007 return ClassUtils.getShortClassName(getCanonicalName(canonicalName));
1008 }
1009
1010 // Package name
1011 // ----------------------------------------------------------------------
1012 /**
1013 * <p>Gets the package name from the canonical name of an {@code Object}.</p>
1014 *
1015 * @param object the class to get the package name for, may be null
1016 * @param valueIfNull the value to return if null
1017 * @return the package name of the object, or the null value
1018 * @since 2.4
1019 */
1020 public static String getPackageCanonicalName(Object object, String valueIfNull) {
1021 if (object == null) {
1022 return valueIfNull;
1023 }
1024 return getPackageCanonicalName(object.getClass().getName());
1025 }
1026
1027 /**
1028 * <p>Gets the package name from the canonical name of a {@code Class}.</p>
1029 *
1030 * @param cls the class to get the package name for, may be {@code null}.
1031 * @return the package name or an empty string
1032 * @since 2.4
1033 */
1034 public static String getPackageCanonicalName(Class<?> cls) {
1035 if (cls == null) {
1036 return StringUtils.EMPTY;
1037 }
1038 return getPackageCanonicalName(cls.getName());
1039 }
1040
1041 /**
1042 * <p>Gets the package name from the canonical name. </p>
1043 *
1044 * <p>The string passed in is assumed to be a canonical name - it is not checked.</p>
1045 * <p>If the class is unpackaged, return an empty string.</p>
1046 *
1047 * @param canonicalName the canonical name to get the package name for, may be {@code null}
1048 * @return the package name or an empty string
1049 * @since 2.4
1050 */
1051 public static String getPackageCanonicalName(String canonicalName) {
1052 return ClassUtils.getPackageName(getCanonicalName(canonicalName));
1053 }
1054
1055 /**
1056 * <p>Converts a given name of class into canonical format.
1057 * If name of class is not a name of array class it returns
1058 * unchanged name.</p>
1059 * <p>Example:
1060 * <ul>
1061 * <li>{@code getCanonicalName("[I") = "int[]"}</li>
1062 * <li>{@code getCanonicalName("[Ljava.lang.String;") = "java.lang.String[]"}</li>
1063 * <li>{@code getCanonicalName("java.lang.String") = "java.lang.String"}</li>
1064 * </ul>
1065 * </p>
1066 *
1067 * @param className the name of class
1068 * @return canonical form of class name
1069 * @since 2.4
1070 */
1071 private static String getCanonicalName(String className) {
1072 className = StringUtils.deleteWhitespace(className);
1073 if (className == null) {
1074 return null;
1075 } else {
1076 int dim = 0;
1077 while (className.startsWith("[")) {
1078 dim++;
1079 className = className.substring(1);
1080 }
1081 if (dim < 1) {
1082 return className;
1083 } else {
1084 if (className.startsWith("L")) {
1085 className = className.substring(
1086 1,
1087 className.endsWith(";")
1088 ? className.length() - 1
1089 : className.length());
1090 } else {
1091 if (className.length() > 0) {
1092 className = reverseAbbreviationMap.get(className.substring(0, 1));
1093 }
1094 }
1095 StringBuilder canonicalClassNameBuffer = new StringBuilder(className);
1096 for (int i = 0; i < dim; i++) {
1097 canonicalClassNameBuffer.append("[]");
1098 }
1099 return canonicalClassNameBuffer.toString();
1100 }
1101 }
1102 }
1103 }