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25 
26 package javax.annotation.processing;
27 
28 import javax.lang.model.element.Element;
29 import javax.lang.model.element.TypeElement;
30 import java.util.LinkedHashSet;
31 import java.util.Collections;
32 import java.util.Set;
33 import java.lang.annotation.Annotation;
34 
35 /**
36  * An annotation processing tool framework will {@linkplain
37  * Processor#process provide an annotation processor with an object
38  * implementing this interface} so that the processor can query for
39  * information about a round of annotation processing.
40  *
41  * @author Joseph D. Darcy
42  * @author Scott Seligman
43  * @author Peter von der Ahé
44  * @since 1.6
45  */
46 public interface RoundEnvironment {
47     /**
48      * Returns {@code true} if types generated by this round will not
49      * be subject to a subsequent round of annotation processing;
50      * returns {@code false} otherwise.
51      *
52      * @return {@code true} if types generated by this round will not
53      * be subject to a subsequent round of annotation processing;
54      * returns {@code false} otherwise
55      */
processingOver()56     boolean processingOver();
57 
58     /**
59      * Returns {@code true} if an error was raised in the prior round
60      * of processing; returns {@code false} otherwise.
61      *
62      * @return {@code true} if an error was raised in the prior round
63      * of processing; returns {@code false} otherwise
64      */
errorRaised()65     boolean errorRaised();
66 
67     /**
68      * Returns the {@linkplain Processor root elements} for annotation processing generated
69      * by the prior round.
70      *
71      * @return the root elements for annotation processing generated
72      * by the prior round, or an empty set if there were none
73      */
getRootElements()74     Set<? extends Element> getRootElements();
75 
76     /**
77      * Returns the elements annotated with the given annotation type.
78      * The annotation may appear directly or be inherited.  Only
79      * package elements, module elements, and type elements <i>included</i> in this
80      * round of annotation processing, or declarations of members,
81      * constructors, parameters, type parameters, or record components
82      * declared within those, are returned.  Included type elements are {@linkplain
83      * #getRootElements root types} and any member types nested within
84      * them.  Elements of a package are not considered included simply
85      * because a {@code package-info} file for that package was
86      * created.
87      * Likewise, elements of a module are not considered included
88      * simply because a {@code module-info} file for that module was
89      * created.
90      *
91      * @param a  annotation type being requested
92      * @return the elements annotated with the given annotation type,
93      * or an empty set if there are none
94      * @throws IllegalArgumentException if the argument does not
95      * represent an annotation type
96      */
getElementsAnnotatedWith(TypeElement a)97     Set<? extends Element> getElementsAnnotatedWith(TypeElement a);
98 
99     /**
100      * Returns the elements annotated with one or more of the given
101      * annotation types.
102      *
103      * @apiNote This method may be useful when processing repeating
104      * annotations by looking for an annotation type and its
105      * containing annotation type at the same time.
106      *
107      * @implSpec The default implementation of this method creates an
108      * empty result set, iterates over the annotations in the argument
109      * array calling {@link #getElementsAnnotatedWith(TypeElement)} on
110      * each annotation and adding those results to the result
111      * set. Finally, the contents of the result set are returned as an
112      * unmodifiable set.
113      *
114      * @param annotations  annotation types being requested
115      * @return the elements annotated with one or more of the given
116      * annotation types, or an empty set if there are none
117      * @throws IllegalArgumentException if the any elements of the
118      * argument set do not represent an annotation type
119      * @jls 9.6.3 Repeatable Annotation Types
120      * @since 9
121      */
getElementsAnnotatedWithAny(TypeElement... annotations)122     default Set<? extends Element> getElementsAnnotatedWithAny(TypeElement... annotations){
123         // Use LinkedHashSet rather than HashSet for predictability
124         Set<Element> result = new LinkedHashSet<>();
125         for (TypeElement annotation : annotations) {
126             result.addAll(getElementsAnnotatedWith(annotation));
127         }
128         return Collections.unmodifiableSet(result);
129     }
130 
131     /**
132      * Returns the elements annotated with the given annotation type.
133      * The annotation may appear directly or be inherited.  Only
134      * package elements, module elements, and type elements <i>included</i> in this
135      * round of annotation processing, or declarations of members,
136      * constructors, parameters, type parameters, or record components
137      * declared within those, are returned.  Included type elements are {@linkplain
138      * #getRootElements root types} and any member types nested within
139      * them.  Elements in a package are not considered included simply
140      * because a {@code package-info} file for that package was
141      * created.
142      * Likewise, elements of a module are not considered included
143      * simply because a {@code module-info} file for that module was
144      * created.
145      *
146      * <p> Note: An implementation of this method typically performs
147      * an internal conversion from the runtime reflective
148      * representation of an annotation type as a {@code Class} object
149      * to a different representation used for annotation
150      * processing. The set of annotation types present in the runtime
151      * context may differ from the set of annotation types present in
152      * the context of annotation processing in a particular
153      * environmental configuration. If an runtime annotation type is
154      * not present in the annotation processing context, the situation
155      * is not treated as an error and no elements are found for that
156      * annotation type.
157      *
158      * @param a  annotation type being requested
159      * @return the elements annotated with the given annotation type,
160      * or an empty set if there are none
161      * @throws IllegalArgumentException if the argument does not
162      * represent an annotation type
163      *
164      * @see javax.lang.model.AnnotatedConstruct#getAnnotation(Class)
165      * @see javax.lang.model.AnnotatedConstruct#getAnnotationsByType(Class)
166      */
getElementsAnnotatedWith(Class<? extends Annotation> a)167     Set<? extends Element> getElementsAnnotatedWith(Class<? extends Annotation> a);
168 
169     /**
170      * Returns the elements annotated with one or more of the given
171      * annotation types.
172      *
173      * <p> Note: An implementation of this method typically performs
174      * an internal conversion from the runtime reflective
175      * representation of an annotation type as a {@code Class} object
176      * to a different representation used for annotation
177      * processing. The set of annotation types present in the runtime
178      * context may differ from the set of annotation types present in
179      * the context of annotation processing in a particular
180      * environmental configuration. If an runtime annotation type is
181      * not present in the annotation processing context, the situation
182      * is not treated as an error and no elements are found for that
183      * annotation type.
184      *
185      * @apiNote This method may be useful when processing repeating
186      * annotations by looking for an annotation type and its
187      * containing annotation type at the same time.
188      *
189      * @implSpec The default implementation of this method creates an
190      * empty result set, iterates over the annotations in the argument
191      * set calling {@link #getElementsAnnotatedWith(Class)} on
192      * each annotation and adding those results to the result
193      * set. Finally, the contents of the result set are returned as an
194      * unmodifiable set.
195      *
196      * @param annotations  annotation types being requested
197      * @return the elements annotated with one or more of the given
198      * annotation types, or an empty set if there are none
199      * @throws IllegalArgumentException if the any elements of the
200      * argument set do not represent an annotation type
201      * @jls 9.6.3 Repeatable Annotation Types
202      *
203      * @see javax.lang.model.AnnotatedConstruct#getAnnotation(Class)
204      * @see javax.lang.model.AnnotatedConstruct#getAnnotationsByType(Class)
205      *
206      * @since 9
207      */
getElementsAnnotatedWithAny(Set<Class<? extends Annotation>> annotations)208     default Set<? extends Element> getElementsAnnotatedWithAny(Set<Class<? extends Annotation>> annotations){
209         // Use LinkedHashSet rather than HashSet for predictability
210         Set<Element> result = new LinkedHashSet<>();
211         for (Class<? extends Annotation> annotation : annotations) {
212             result.addAll(getElementsAnnotatedWith(annotation));
213         }
214         return Collections.unmodifiableSet(result);
215     }
216 }
217