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