Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
GenericsUtils |
|
| 0.0;0 |
1 | /* | |
2 | * $Id: GenericsUtils.java 20321 2010-11-24 15:21:24Z dfeist $ | |
3 | * -------------------------------------------------------------------------------------- | |
4 | * Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com | |
5 | * | |
6 | * The software in this package is published under the terms of the CPAL v1.0 | |
7 | * license, a copy of which has been included with this distribution in the | |
8 | * LICENSE.txt file. | |
9 | */ | |
10 | package org.mule.util.generics; | |
11 | ||
12 | import java.lang.reflect.Array; | |
13 | import java.lang.reflect.Field; | |
14 | import java.lang.reflect.GenericArrayType; | |
15 | import java.lang.reflect.Method; | |
16 | import java.lang.reflect.ParameterizedType; | |
17 | import java.lang.reflect.Type; | |
18 | import java.lang.reflect.TypeVariable; | |
19 | import java.lang.reflect.WildcardType; | |
20 | import java.util.Collection; | |
21 | import java.util.Map; | |
22 | ||
23 | /** | |
24 | * Helper class for determining element types of collections and maps. | |
25 | * <p/> | |
26 | * <p>Mainly intended for usage within the framework, determining the | |
27 | * target type of values to be added to a collection or map | |
28 | * (to be able to attempt type conversion if appropriate). | |
29 | * <p/> | |
30 | * author: Spring | |
31 | */ | |
32 | 0 | public class GenericsUtils |
33 | { | |
34 | ||
35 | ||
36 | /** | |
37 | * Determine the generic element type of the given Collection class | |
38 | * (if it declares one through a generic superclass or generic interface). | |
39 | * | |
40 | * @param collectionClass the collection class to introspect | |
41 | * @return the generic type, or <code>null</code> if none | |
42 | */ | |
43 | public static Class<?> getCollectionType(Class<? extends Collection<?>> collectionClass) | |
44 | { | |
45 | 0 | return extractTypeFromClass(collectionClass, Collection.class, 0); |
46 | } | |
47 | ||
48 | /** | |
49 | * Determine the generic key type of the given Map class | |
50 | * (if it declares one through a generic superclass or generic interface). | |
51 | * | |
52 | * @param mapClass the map class to introspect | |
53 | * @return the generic type, or <code>null</code> if none | |
54 | */ | |
55 | public static Class<?> getMapKeyType(Class<? extends Map<?, ?>> mapClass) | |
56 | { | |
57 | 0 | return extractTypeFromClass(mapClass, Map.class, 0); |
58 | } | |
59 | ||
60 | /** | |
61 | * Determine the generic value type of the given Map class | |
62 | * (if it declares one through a generic superclass or generic interface). | |
63 | * | |
64 | * @param mapClass the map class to introspect | |
65 | * @return the generic type, or <code>null</code> if none | |
66 | */ | |
67 | public static Class<?> getMapValueType(Class<? extends Map<?, ?>> mapClass) | |
68 | { | |
69 | 0 | return extractTypeFromClass(mapClass, Map.class, 1); |
70 | } | |
71 | ||
72 | /** | |
73 | * Determine the generic element type of the given Collection field. | |
74 | * | |
75 | * @param collectionField the collection field to introspect | |
76 | * @return the generic type, or <code>null</code> if none | |
77 | */ | |
78 | public static Class<?> getCollectionFieldType(Field collectionField) | |
79 | { | |
80 | 0 | return getGenericFieldType(collectionField, Collection.class, 0, 1); |
81 | } | |
82 | ||
83 | /** | |
84 | * Determine the generic element type of the given Collection field. | |
85 | * | |
86 | * @param collectionField the collection field to introspect | |
87 | * @param nestingLevel the nesting level of the target type | |
88 | * (typically 1; e.g. in case of a List of Lists, 1 would indicate the | |
89 | * nested List, whereas 2 would indicate the element of the nested List) | |
90 | * @return the generic type, or <code>null</code> if none | |
91 | */ | |
92 | public static Class<?> getCollectionFieldType(Field collectionField, int nestingLevel) | |
93 | { | |
94 | 0 | return getGenericFieldType(collectionField, Collection.class, 0, nestingLevel); |
95 | } | |
96 | ||
97 | /** | |
98 | * Determine the generic key type of the given Map field. | |
99 | * | |
100 | * @param mapField the map field to introspect | |
101 | * @return the generic type, or <code>null</code> if none | |
102 | */ | |
103 | public static Class<?> getMapKeyFieldType(Field mapField) | |
104 | { | |
105 | 0 | return getGenericFieldType(mapField, Map.class, 0, 1); |
106 | } | |
107 | ||
108 | /** | |
109 | * Determine the generic key type of the given Map field. | |
110 | * | |
111 | * @param mapField the map field to introspect | |
112 | * @param nestingLevel the nesting level of the target type | |
113 | * (typically 1; e.g. in case of a List of Lists, 1 would indicate the | |
114 | * nested List, whereas 2 would indicate the element of the nested List) | |
115 | * @return the generic type, or <code>null</code> if none | |
116 | */ | |
117 | public static Class<?> getMapKeyFieldType(Field mapField, int nestingLevel) | |
118 | { | |
119 | 0 | return getGenericFieldType(mapField, Map.class, 0, nestingLevel); |
120 | } | |
121 | ||
122 | /** | |
123 | * Determine the generic value type of the given Map field. | |
124 | * | |
125 | * @param mapField the map field to introspect | |
126 | * @return the generic type, or <code>null</code> if none | |
127 | */ | |
128 | public static Class<?> getMapValueFieldType(Field mapField) | |
129 | { | |
130 | 0 | return getGenericFieldType(mapField, Map.class, 1, 1); |
131 | } | |
132 | ||
133 | /** | |
134 | * Determine the generic value type of the given Map field. | |
135 | * | |
136 | * @param mapField the map field to introspect | |
137 | * @param nestingLevel the nesting level of the target type | |
138 | * (typically 1; e.g. in case of a List of Lists, 1 would indicate the | |
139 | * nested List, whereas 2 would indicate the element of the nested List) | |
140 | * @return the generic type, or <code>null</code> if none | |
141 | */ | |
142 | public static Class<?> getMapValueFieldType(Field mapField, int nestingLevel) | |
143 | { | |
144 | 0 | return getGenericFieldType(mapField, Map.class, 1, nestingLevel); |
145 | } | |
146 | ||
147 | /** | |
148 | * Determine the generic element type of the given Collection parameter. | |
149 | * | |
150 | * @param methodParam the method parameter specification | |
151 | * @return the generic type, or <code>null</code> if none | |
152 | */ | |
153 | public static Class<?> getCollectionParameterType(MethodParameter methodParam) | |
154 | { | |
155 | 0 | return getGenericParameterType(methodParam, Collection.class, 0); |
156 | } | |
157 | ||
158 | /** | |
159 | * Determine the generic key type of the given Map parameter. | |
160 | * | |
161 | * @param methodParam the method parameter specification | |
162 | * @return the generic type, or <code>null</code> if none | |
163 | */ | |
164 | public static Class<?> getMapKeyParameterType(MethodParameter methodParam) | |
165 | { | |
166 | 0 | return getGenericParameterType(methodParam, Map.class, 0); |
167 | } | |
168 | ||
169 | /** | |
170 | * Determine the generic value type of the given Map parameter. | |
171 | * | |
172 | * @param methodParam the method parameter specification | |
173 | * @return the generic type, or <code>null</code> if none | |
174 | */ | |
175 | public static Class<?> getMapValueParameterType(MethodParameter methodParam) | |
176 | { | |
177 | 0 | return getGenericParameterType(methodParam, Map.class, 1); |
178 | } | |
179 | ||
180 | /** | |
181 | * Determine the generic element type of the given Collection return type. | |
182 | * | |
183 | * @param method the method to check the return type for | |
184 | * @return the generic type, or <code>null</code> if none | |
185 | */ | |
186 | public static Class<?> getCollectionReturnType(Method method) | |
187 | { | |
188 | 0 | return getGenericReturnType(method, Collection.class, 0, 1); |
189 | } | |
190 | ||
191 | /** | |
192 | * Determine the generic element type of the given Collection return type. | |
193 | * <p>If the specified nesting level is higher than 1, the element type of | |
194 | * a nested Collection/Map will be analyzed. | |
195 | * | |
196 | * @param method the method to check the return type for | |
197 | * @param nestingLevel the nesting level of the target type | |
198 | * (typically 1; e.g. in case of a List of Lists, 1 would indicate the | |
199 | * nested List, whereas 2 would indicate the element of the nested List) | |
200 | * @return the generic type, or <code>null</code> if none | |
201 | */ | |
202 | public static Class<?> getCollectionReturnType(Method method, int nestingLevel) | |
203 | { | |
204 | 0 | return getGenericReturnType(method, Collection.class, 0, nestingLevel); |
205 | } | |
206 | ||
207 | /** | |
208 | * Determine the generic key type of the given Map return type. | |
209 | * | |
210 | * @param method the method to check the return type for | |
211 | * @return the generic type, or <code>null</code> if none | |
212 | */ | |
213 | public static Class<?> getMapKeyReturnType(Method method) | |
214 | { | |
215 | 0 | return getGenericReturnType(method, Map.class, 0, 1); |
216 | } | |
217 | ||
218 | /** | |
219 | * Determine the generic key type of the given Map return type. | |
220 | * | |
221 | * @param method the method to check the return type for | |
222 | * @param nestingLevel the nesting level of the target type | |
223 | * (typically 1; e.g. in case of a List of Lists, 1 would indicate the | |
224 | * nested List, whereas 2 would indicate the element of the nested List) | |
225 | * @return the generic type, or <code>null</code> if none | |
226 | */ | |
227 | public static Class<?> getMapKeyReturnType(Method method, int nestingLevel) | |
228 | { | |
229 | 0 | return getGenericReturnType(method, Map.class, 0, nestingLevel); |
230 | } | |
231 | ||
232 | /** | |
233 | * Determine the generic value type of the given Map return type. | |
234 | * | |
235 | * @param method the method to check the return type for | |
236 | * @return the generic type, or <code>null</code> if none | |
237 | */ | |
238 | public static Class<?> getMapValueReturnType(Method method) | |
239 | { | |
240 | 0 | return getGenericReturnType(method, Map.class, 1, 1); |
241 | } | |
242 | ||
243 | /** | |
244 | * Determine the generic value type of the given Map return type. | |
245 | * | |
246 | * @param method the method to check the return type for | |
247 | * @param nestingLevel the nesting level of the target type | |
248 | * (typically 1; e.g. in case of a List of Lists, 1 would indicate the | |
249 | * nested List, whereas 2 would indicate the element of the nested List) | |
250 | * @return the generic type, or <code>null</code> if none | |
251 | */ | |
252 | public static Class<?> getMapValueReturnType(Method method, int nestingLevel) | |
253 | { | |
254 | 0 | return getGenericReturnType(method, Map.class, 1, nestingLevel); |
255 | } | |
256 | ||
257 | ||
258 | /** | |
259 | * Extract the generic parameter type from the given method or constructor. | |
260 | * | |
261 | * @param methodParam the method parameter specification | |
262 | * @param source the source class/interface defining the generic parameter types | |
263 | * @param typeIndex the index of the type (e.g. 0 for Collections, | |
264 | * 0 for Map keys, 1 for Map values) | |
265 | * @return the generic type, or <code>null</code> if none | |
266 | */ | |
267 | private static Class<?> getGenericParameterType(MethodParameter methodParam, Class<?> source, int typeIndex) | |
268 | { | |
269 | 0 | return extractType(methodParam, GenericTypeResolver.getTargetType(methodParam), |
270 | source, typeIndex, methodParam.getNestingLevel(), 1); | |
271 | } | |
272 | ||
273 | /** | |
274 | * Extract the generic type from the given field. | |
275 | * | |
276 | * @param field the field to check the type for | |
277 | * @param source the source class/interface defining the generic parameter types | |
278 | * @param typeIndex the index of the type (e.g. 0 for Collections, | |
279 | * 0 for Map keys, 1 for Map values) | |
280 | * @param nestingLevel the nesting level of the target type | |
281 | * @return the generic type, or <code>null</code> if none | |
282 | */ | |
283 | private static Class<?> getGenericFieldType(Field field, Class<?> source, int typeIndex, int nestingLevel) | |
284 | { | |
285 | 0 | return extractType(null, field.getGenericType(), source, typeIndex, nestingLevel, 1); |
286 | } | |
287 | ||
288 | /** | |
289 | * Extract the generic return type from the given method. | |
290 | * | |
291 | * @param method the method to check the return type for | |
292 | * @param source the source class/interface defining the generic parameter types | |
293 | * @param typeIndex the index of the type (e.g. 0 for Collections, | |
294 | * 0 for Map keys, 1 for Map values) | |
295 | * @param nestingLevel the nesting level of the target type | |
296 | * @return the generic type, or <code>null</code> if none | |
297 | */ | |
298 | private static Class<?> getGenericReturnType(Method method, Class<?> source, int typeIndex, int nestingLevel) | |
299 | { | |
300 | 0 | return extractType(null, method.getGenericReturnType(), source, typeIndex, nestingLevel, 1); |
301 | } | |
302 | ||
303 | /** | |
304 | * Extract the generic type from the given Type object. | |
305 | * | |
306 | * @param methodParam the method parameter specification | |
307 | * @param type the Type to check | |
308 | * @param source the source collection/map Class<?> that we check | |
309 | * @param typeIndex the index of the actual type argument | |
310 | * @param nestingLevel the nesting level of the target type | |
311 | * @param currentLevel the current nested level | |
312 | * @return the generic type as Class, or <code>null</code> if none | |
313 | */ | |
314 | private static Class<?> extractType(MethodParameter methodParam, Type type, Class<?> source, | |
315 | int typeIndex, int nestingLevel, int currentLevel) | |
316 | { | |
317 | 0 | Type resolvedType = type; |
318 | 0 | if (type instanceof TypeVariable<?> && methodParam != null && methodParam.typeVariableMap != null) |
319 | { | |
320 | 0 | Type mappedType = methodParam.typeVariableMap.get(type); |
321 | 0 | if (mappedType != null) |
322 | { | |
323 | 0 | resolvedType = mappedType; |
324 | } | |
325 | } | |
326 | 0 | if (resolvedType instanceof ParameterizedType) |
327 | { | |
328 | 0 | return extractTypeFromParameterizedType( |
329 | methodParam, (ParameterizedType) resolvedType, source, typeIndex, nestingLevel, currentLevel); | |
330 | } | |
331 | 0 | else if (resolvedType instanceof Class<?>) |
332 | { | |
333 | 0 | Class<?> resolvedClass = (Class<?>) resolvedType; |
334 | 0 | return extractTypeFromClass(methodParam, resolvedClass, source, typeIndex, nestingLevel, currentLevel); |
335 | } | |
336 | else | |
337 | { | |
338 | 0 | return null; |
339 | } | |
340 | } | |
341 | ||
342 | /** | |
343 | * Extract the generic type from the given ParameterizedType object. | |
344 | * | |
345 | * @param methodParam the method parameter specification | |
346 | * @param ptype the ParameterizedType to check | |
347 | * @param source the expected raw source type (can be <code>null</code>) | |
348 | * @param typeIndex the index of the actual type argument | |
349 | * @param nestingLevel the nesting level of the target type | |
350 | * @param currentLevel the current nested level | |
351 | * @return the generic type as Class, or <code>null</code> if none | |
352 | */ | |
353 | private static Class<?> extractTypeFromParameterizedType(MethodParameter methodParam, | |
354 | ParameterizedType ptype, Class<?> source, int typeIndex, int nestingLevel, int currentLevel) | |
355 | { | |
356 | ||
357 | 0 | if (!(ptype.getRawType() instanceof Class<?>)) |
358 | { | |
359 | 0 | return null; |
360 | } | |
361 | ||
362 | 0 | Class<?> rawType = (Class<?>) ptype.getRawType(); |
363 | 0 | Type[] paramTypes = ptype.getActualTypeArguments(); |
364 | 0 | if (nestingLevel - currentLevel > 0) |
365 | { | |
366 | 0 | int nextLevel = currentLevel + 1; |
367 | 0 | Integer currentTypeIndex = (methodParam != null ? methodParam.getTypeIndexForLevel(nextLevel) : null); |
368 | // Default is last parameter type: Collection element or Map value. | |
369 | 0 | int indexToUse = (currentTypeIndex != null ? currentTypeIndex : paramTypes.length - 1); |
370 | 0 | Type paramType = paramTypes[indexToUse]; |
371 | 0 | return extractType(methodParam, paramType, source, typeIndex, nestingLevel, nextLevel); |
372 | } | |
373 | 0 | if (source != null && !source.isAssignableFrom(rawType)) |
374 | { | |
375 | 0 | return null; |
376 | } | |
377 | 0 | Class<?> fromSuperclassOrInterface = |
378 | extractTypeFromClass(methodParam, rawType, source, typeIndex, nestingLevel, currentLevel); | |
379 | 0 | if (fromSuperclassOrInterface != null) |
380 | { | |
381 | 0 | return fromSuperclassOrInterface; |
382 | } | |
383 | 0 | if (paramTypes == null || typeIndex >= paramTypes.length) |
384 | { | |
385 | 0 | return null; |
386 | } | |
387 | 0 | Type paramType = paramTypes[typeIndex]; |
388 | 0 | if (paramType instanceof TypeVariable<?> && methodParam != null && methodParam.typeVariableMap != null) |
389 | { | |
390 | 0 | Type mappedType = methodParam.typeVariableMap.get(paramType); |
391 | 0 | if (mappedType != null) |
392 | { | |
393 | 0 | paramType = mappedType; |
394 | } | |
395 | } | |
396 | 0 | if (paramType instanceof WildcardType) |
397 | { | |
398 | 0 | WildcardType wildcardType = (WildcardType) paramType; |
399 | 0 | Type[] upperBounds = wildcardType.getUpperBounds(); |
400 | 0 | if (upperBounds != null && upperBounds.length > 0 && !Object.class.equals(upperBounds[0])) |
401 | { | |
402 | 0 | paramType = upperBounds[0]; |
403 | } | |
404 | else | |
405 | { | |
406 | 0 | Type[] lowerBounds = wildcardType.getLowerBounds(); |
407 | 0 | if (lowerBounds != null && lowerBounds.length > 0 && !Object.class.equals(lowerBounds[0])) |
408 | { | |
409 | 0 | paramType = lowerBounds[0]; |
410 | } | |
411 | } | |
412 | } | |
413 | 0 | if (paramType instanceof ParameterizedType) |
414 | { | |
415 | 0 | paramType = ((ParameterizedType) paramType).getRawType(); |
416 | } | |
417 | 0 | if (paramType instanceof GenericArrayType) |
418 | { | |
419 | // A generic array type... Let's turn it into a straight array type if possible. | |
420 | 0 | Type compType = ((GenericArrayType) paramType).getGenericComponentType(); |
421 | 0 | if (compType instanceof Class<?>) |
422 | { | |
423 | 0 | Class<?> compClass = (Class<?>) compType; |
424 | 0 | return Array.newInstance(compClass, 0).getClass(); |
425 | } | |
426 | 0 | } |
427 | 0 | else if (paramType instanceof Class<?>) |
428 | { | |
429 | // We finally got a straight Class... | |
430 | 0 | return (Class<?>) paramType; |
431 | } | |
432 | 0 | return null; |
433 | } | |
434 | ||
435 | /** | |
436 | * Extract the generic type from the given Class<?> object. | |
437 | * | |
438 | * @param clazz the Class<?> to check | |
439 | * @param source the expected raw source type (can be <code>null</code>) | |
440 | * @param typeIndex the index of the actual type argument | |
441 | * @return the generic type as Class, or <code>null</code> if none | |
442 | */ | |
443 | private static Class<?> extractTypeFromClass(Class<?> clazz, Class<?> source, int typeIndex) | |
444 | { | |
445 | 0 | return extractTypeFromClass(null, clazz, source, typeIndex, 1, 1); |
446 | } | |
447 | ||
448 | /** | |
449 | * Extract the generic type from the given Class<?> object. | |
450 | * | |
451 | * @param methodParam the method parameter specification | |
452 | * @param clazz the Class<?> to check | |
453 | * @param source the expected raw source type (can be <code>null</code>) | |
454 | * @param typeIndex the index of the actual type argument | |
455 | * @param nestingLevel the nesting level of the target type | |
456 | * @param currentLevel the current nested level | |
457 | * @return the generic type as Class, or <code>null</code> if none | |
458 | */ | |
459 | private static Class<?> extractTypeFromClass( | |
460 | MethodParameter methodParam, Class<?> clazz, Class<?> source, int typeIndex, int nestingLevel, int currentLevel) | |
461 | { | |
462 | ||
463 | 0 | if (clazz.getName().startsWith("java.util.")) |
464 | { | |
465 | 0 | return null; |
466 | } | |
467 | 0 | if (clazz.getSuperclass() != null && isIntrospectionCandidate(clazz.getSuperclass())) |
468 | { | |
469 | 0 | return extractType(methodParam, clazz.getGenericSuperclass(), source, typeIndex, nestingLevel, currentLevel); |
470 | } | |
471 | 0 | Type[] ifcs = clazz.getGenericInterfaces(); |
472 | 0 | if (ifcs != null) |
473 | { | |
474 | 0 | for (Type ifc : ifcs) |
475 | { | |
476 | 0 | Type rawType = ifc; |
477 | 0 | if (ifc instanceof ParameterizedType) |
478 | { | |
479 | 0 | rawType = ((ParameterizedType) ifc).getRawType(); |
480 | } | |
481 | 0 | if (rawType instanceof Class<?> && isIntrospectionCandidate((Class<?>) rawType)) |
482 | { | |
483 | 0 | return extractType(methodParam, ifc, source, typeIndex, nestingLevel, currentLevel); |
484 | } | |
485 | } | |
486 | } | |
487 | 0 | return null; |
488 | } | |
489 | ||
490 | /** | |
491 | * Determine whether the given class is a potential candidate | |
492 | * that defines generic collection or map types. | |
493 | * | |
494 | * @param clazz the class to check | |
495 | * @return whether the given class is assignable to Collection or Map | |
496 | */ | |
497 | private static boolean isIntrospectionCandidate(Class<?> clazz) | |
498 | { | |
499 | 0 | return (Collection.class.isAssignableFrom(clazz) || Map.class.isAssignableFrom(clazz)); |
500 | } | |
501 | ||
502 | } | |
503 |