69
70 /** Helper to get the container, or null if none, of an annotation. */
71 private static <A extends Annotation> Class<? extends Annotation> getContainer(Class<A> annotationClass) {
72 Repeatable containingAnnotation = annotationClass.getDeclaredAnnotation(Repeatable.class);
73 return (containingAnnotation == null) ? null : containingAnnotation.value();
74 }
75
76 /** Reflectively look up and get the returned array from the the
77 * invocation of the value() element on an instance of an
78 * Annotation.
79 */
80 private static <A extends Annotation> A[] getValueArray(Annotation containerInstance) {
81 try {
82 // the spec tells us the container must have an array-valued
83 // value element. Get the AnnotationType, get the "value" element
84 // and invoke it to get the contents.
85
86 Class<? extends Annotation> containerClass = containerInstance.annotationType();
87 AnnotationType annoType = AnnotationType.getInstance(containerClass);
88 if (annoType == null)
89 throw new InvalidContainerAnnotationError(containerInstance + " is an invalid container for repeating annotations");
90
91 Method m = annoType.members().get("value");
92 if (m == null)
93 throw new InvalidContainerAnnotationError(containerInstance +
94 " is an invalid container for repeating annotations");
95 m.setAccessible(true);
96
97 @SuppressWarnings("unchecked") // not provably safe, but we catch the ClassCastException
98 A[] a = (A[])m.invoke(containerInstance); // this will erase to (Annotation[]) but we
99 // do a runtime cast on the return-value
100 // in the methods that call this method
101 return a;
102 } catch (IllegalAccessException | // couldnt loosen security
103 IllegalArgumentException | // parameters doesn't match
104 InvocationTargetException | // the value method threw an exception
105 ClassCastException e) { // well, a cast failed ...
106 throw new InvalidContainerAnnotationError(
107 containerInstance + " is an invalid container for repeating annotations",
108 e,
109 containerInstance,
110 null);
111 }
112 }
113
114 /* Sanity check type of and return a list of all the annotation
115 * instances of type {@code annotationClass} from {@code
116 * containerInstance}.
117 */
118 private static <A extends Annotation> List<A> unpackAll(Annotation containerInstance,
119 Class<A> annotationClass) {
120 if (containerInstance == null) {
121 return Collections.emptyList(); // container not present
122 }
123
124 try {
125 A[] a = getValueArray(containerInstance);
126 List<A> l = new ArrayList<>(a.length);
127 for (int i = 0; i < a.length; i++)
128 l.add(annotationClass.cast(a[i]));
129 return l;
130 } catch (ClassCastException |
131 NullPointerException e) {
132 throw new InvalidContainerAnnotationError(
133 String.format("%s is an invalid container for repeating annotations of type: %s",
134 containerInstance, annotationClass),
135 e,
136 containerInstance,
137 annotationClass);
138 }
139 }
140 }
|
69
70 /** Helper to get the container, or null if none, of an annotation. */
71 private static <A extends Annotation> Class<? extends Annotation> getContainer(Class<A> annotationClass) {
72 Repeatable containingAnnotation = annotationClass.getDeclaredAnnotation(Repeatable.class);
73 return (containingAnnotation == null) ? null : containingAnnotation.value();
74 }
75
76 /** Reflectively look up and get the returned array from the the
77 * invocation of the value() element on an instance of an
78 * Annotation.
79 */
80 private static <A extends Annotation> A[] getValueArray(Annotation containerInstance) {
81 try {
82 // the spec tells us the container must have an array-valued
83 // value element. Get the AnnotationType, get the "value" element
84 // and invoke it to get the contents.
85
86 Class<? extends Annotation> containerClass = containerInstance.annotationType();
87 AnnotationType annoType = AnnotationType.getInstance(containerClass);
88 if (annoType == null)
89 throw new AnnotationFormatError(containerInstance + " is an invalid container for repeating annotations");
90
91 Method m = annoType.members().get("value");
92 if (m == null)
93 throw new AnnotationFormatError(containerInstance +
94 " is an invalid container for repeating annotations");
95 m.setAccessible(true);
96
97 @SuppressWarnings("unchecked") // not provably safe, but we catch the ClassCastException
98 A[] a = (A[])m.invoke(containerInstance); // this will erase to (Annotation[]) but we
99 // do a runtime cast on the return-value
100 // in the methods that call this method
101 return a;
102 } catch (IllegalAccessException | // couldnt loosen security
103 IllegalArgumentException | // parameters doesn't match
104 InvocationTargetException | // the value method threw an exception
105 ClassCastException e) { // well, a cast failed ...
106 throw new AnnotationFormatError(
107 containerInstance + " is an invalid container for repeating annotations",
108 e);
109 }
110 }
111
112 /* Sanity check type of and return a list of all the annotation
113 * instances of type {@code annotationClass} from {@code
114 * containerInstance}.
115 */
116 private static <A extends Annotation> List<A> unpackAll(Annotation containerInstance,
117 Class<A> annotationClass) {
118 if (containerInstance == null) {
119 return Collections.emptyList(); // container not present
120 }
121
122 try {
123 A[] a = getValueArray(containerInstance);
124 List<A> l = new ArrayList<>(a.length);
125 for (int i = 0; i < a.length; i++)
126 l.add(annotationClass.cast(a[i]));
127 return l;
128 } catch (ClassCastException |
129 NullPointerException e) {
130 throw new AnnotationFormatError(
131 String.format("%s is an invalid container for repeating annotations of type: %s",
132 containerInstance, annotationClass),
133 e);
134 }
135 }
136 }
|