AnnotatedElement


1   /*
2    * @(#)AnnotatedElement.java    1.3 04/02/03
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package java.lang.reflect;
9   
10  import java.lang.annotation.Annotation  ;
11  
12  /**
13   * Represents an annotated element of the program currently running in this
14   * VM.  This interface allows annotations to be read reflectively.  All
15   * annotations returned by methods in this interface are immutable and
16   * serializable.  It is permissible for the caller to modify the
17   * arrays returned by accessors for array-valued enum members; it will
18   * have no affect on the arrays returned to other callers.
19   *
20   * <p>If an annotation returned by a method in this interface contains
21   * (directly or indirectly) a {@link Class}-valued member referring to
22   * a class that is not accessible in this VM, attempting to read the class
23   * by calling the relevant Class-returning method on the returned annotation
24   * will result in a {@link TypeNotPresentException}.
25   *
26   * <p>Similarly, attempting to read an enum-valued member will result in
27   * a {@link EnumConstantNotPresentException} if the enum constant in the
28   * annotation is no longer present in the enum type.
29   * 
30   * <p>Finally, Attempting to read a member whose definition has evolved
31   * incompatibly will result in a {@link
32   * java.lang.annotation.AnnotationTypeMismatchException} or an
33   * {@link java.lang.annotation.IncompleteAnnotationException}.
34   *
35   * @since 1.5
36   * @author Josh Bloch
37   */
38  public interface AnnotatedElement {
39      /**
40       * Returns true if an annotation for the specified type
41       * is present on this element, else false.  This method
42       * is designed primarily for convenient access to marker annotations.
43       *
44       * @param annotationType the Class object corresponding to the
45       *        annotation type
46       * @return true if an annotation for the specified annotation
47       *     type is present on this element, else false
48       * @throws NullPointerException if annotationType is null
49       * @since 1.5
50       */
51       boolean isAnnotationPresent(Class  <? extends Annotation  > annotationType);
52  
53     /**
54       * Returns this element's annotation for the specified type if
55       * such an annotation is present, else null.
56       *
57       * @param annotationType the Class object corresponding to the 
58       *        annotation type
59       * @return this element's annotation for the specified annotation type if
60       *     present on this element, else null
61       * @throws NullPointerException if annotationType is null
62       * @since 1.5
63       */
64      <T extends Annotation  > T getAnnotation(Class  <T> annotationType);
65  
66      /**
67       * Returns all annotations present on this element.  (Returns an array
68       * of length zero if this element has no annotations.)  The caller of
69       * this method is free to modify the returned array; it will have no
70       * effect on the arrays returned to other callers.
71       *
72       * @return all annotations present on this element
73       * @since 1.5
74       */
75      Annotation  [] getAnnotations();
76  
77      /**
78       * Returns all annotations that are directly present on this
79       * element.  Unlike the other methods in this interface, this method
80       * ignores inherited annotations.  (Returns an array of length zero if
81       * no annotations are directly present on this element.)  The caller of
82       * this method is free to modify the returned array; it will have no
83       * effect on the arrays returned to other callers.
84       *
85       * @return All annotations directly present on this element
86       * @since 1.5
87       */
88      Annotation  [] getDeclaredAnnotations();
89  }
90
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