Package org.junit.platform.commons.support

Class AnnotationSupport

java.lang.Object
org.junit.platform.commons.support.AnnotationSupport
@API(status=MAINTAINED, since="1.0") public final class AnnotationSupport extends Object
AnnotationSupport provides static utility methods for common tasks regarding annotations — for example, checking if a class, method, or field is annotated with a particular annotation; finding annotations on a given class, method, or field; finding fields or methods annotated with a particular annotation, etc.

TestEngine and extension authors are encouraged to use these supported methods in order to align with the behavior of the JUnit Platform.

Since:
1.0
See Also:

  • Method Details

    • isAnnotated

      @API(status=MAINTAINED, since="1.3") public static boolean isAnnotated(Optional<? extends AnnotatedElement> element, Class<? extends Annotation> annotationType)
      Determine if an annotation of annotationType is either present or meta-present on the supplied optional element.
      Parameters:
      element - an Optional containing the element on which to search for the annotation; may be null or empty
      annotationType - the annotation type to search for; never null
      Returns:
      true if the annotation is present or meta-present
      Since:
      1.3
      See Also:

    • isAnnotated

      public static boolean isAnnotated(AnnotatedElement element, Class<? extends Annotation> annotationType)
      Determine if an annotation of annotationType is either present or meta-present on the supplied element.
      Parameters:
      element - the element on which to search for the annotation; may be null
      annotationType - the annotation type to search for; never null
      Returns:
      true if the annotation is present or meta-present
      See Also:

    • findAnnotation

      @API(status=MAINTAINED, since="1.1") public static <A extends Annotation> Optional<A> findAnnotation(Optional<? extends AnnotatedElement> element, Class<A> annotationType)
      Find the first annotation of annotationType that is either present or meta-present on the supplied optional element.
      Type Parameters:
      A - the annotation type
      Parameters:
      element - an Optional containing the element on which to search for the annotation; may be null or empty
      annotationType - the annotation type to search for; never null
      Returns:
      an Optional containing the annotation; never null but potentially empty
      Since:
      1.1
      See Also:

    • findAnnotation

      public static <A extends Annotation> Optional<A> findAnnotation(AnnotatedElement element, Class<A> annotationType)
      Find the first annotation of annotationType that is either directly present, meta-present, or indirectly present on the supplied element.

      If the element is a class and the annotation is neither directly present nor meta-present on the class, this method will additionally search on interfaces implemented by the class before finding an annotation that is indirectly present on the class.

      Type Parameters:
      A - the annotation type
      Parameters:
      element - the element on which to search for the annotation; may be null
      annotationType - the annotation type to search for; never null
      Returns:
      an Optional containing the annotation; never null but potentially empty

    • findAnnotation

      @API(status=EXPERIMENTAL, since="1.8") public static <A extends Annotation> Optional<A> findAnnotation(Class<?> clazz, Class<A> annotationType, SearchOption searchOption)
      Find the first annotation of the specified type that is either directly present, meta-present, or indirectly present on the supplied class.

      If the annotation is neither directly present nor meta-present on the class, this method will additionally search on interfaces implemented by the class before searching for an annotation that is indirectly present on the class (i.e., within the class inheritance hierarchy).

      If the annotation still has not been found, this method will optionally search recursively through the enclosing class hierarchy if SearchOption.INCLUDE_ENCLOSING_CLASSES is specified.

      If SearchOption.DEFAULT is specified, this method has the same semantics as findAnnotation(AnnotatedElement, Class).

      Type Parameters:
      A - the annotation type
      Parameters:
      clazz - the class on which to search for the annotation; may be null
      annotationType - the annotation type to search for; never null
      searchOption - the SearchOption to use; never null
      Returns:
      an Optional containing the annotation; never null but potentially empty
      Since:
      1.8
      See Also:

    • findRepeatableAnnotations

      @API(status=MAINTAINED, since="1.5") public static <A extends Annotation> List<A> findRepeatableAnnotations(Optional<? extends AnnotatedElement> element, Class<A> annotationType)
      Find all repeatable annotations of the supplied annotationType that are either present, indirectly present, or meta-present on the supplied optional element.

      See findRepeatableAnnotations(AnnotatedElement, Class) for details of the algorithm used.

      Type Parameters:
      A - the annotation type
      Parameters:
      element - an Optional containing the element on which to search for the annotation; may be null or empty
      annotationType - the repeatable annotation type to search for; never null
      Returns:
      an immutable list of all such annotations found; never null
      Since:
      1.5
      See Also:

    • findRepeatableAnnotations

      public static <A extends Annotation> List<A> findRepeatableAnnotations(AnnotatedElement element, Class<A> annotationType)
      Find all repeatable annotations of the supplied annotationType that are either present, indirectly present, or meta-present on the supplied AnnotatedElement.

      This method extends the functionality of AnnotatedElement.getAnnotationsByType(Class) with additional support for meta-annotations.

      In addition, if the element is a class and the repeatable annotation is @Inherited, this method will search on superclasses first in order to support top-down semantics. The result is that this algorithm finds repeatable annotations that would be shadowed and therefore not visible according to Java's standard semantics for inherited, repeatable annotations, but most developers will naturally assume that all repeatable annotations in JUnit are discovered regardless of whether they are declared stand-alone, in a container, or as a meta-annotation (e.g., multiple declarations of @ExtendWith within a test class hierarchy).

      If the element is a class and the repeatable annotation is not discovered within the class hierarchy, this method will additionally search on interfaces implemented by each class in the hierarchy.

      If the supplied element is null, this method returns an empty list.

      As of JUnit Platform 1.5, the search algorithm will also find repeatable annotations used as meta-annotations on other repeatable annotations.

      Type Parameters:
      A - the annotation type
      Parameters:
      element - the element to search on; may be null
      annotationType - the repeatable annotation type to search for; never null
      Returns:
      an immutable list of all such annotations found; never null
      See Also:

    • findPublicAnnotatedFields

      public static List<Field> findPublicAnnotatedFields(Class<?> clazz, Class<?> fieldType, Class<? extends Annotation> annotationType)
      Find all public fields of the supplied class or interface that are declared to be of the specified fieldType and are annotated or meta-annotated with the specified annotationType.

      Consult the Javadoc for Class.getFields() for details on inheritance and ordering.

      Parameters:
      clazz - the class or interface in which to find the fields; never null
      fieldType - the declared type of fields to find; never null
      annotationType - the annotation type to search for; never null
      Returns:
      the list of all such fields found; neither null nor mutable
      See Also:

    • findAnnotatedFields

      @API(status=MAINTAINED, since="1.4") public static List<Field> findAnnotatedFields(Class<?> clazz, Class<? extends Annotation> annotationType)
      Find all fields of the supplied class or interface that are annotated or meta-annotated with the specified annotationType, using top-down search semantics within the type hierarchy.

      Fields declared in the same class or interface will be ordered using an algorithm that is deterministic but intentionally nonobvious.

      The results will not contain fields that are hidden or synthetic.

      Parameters:
      clazz - the class or interface in which to find the fields; never null
      annotationType - the annotation type to search for; never null
      Returns:
      the list of all such fields found; neither null nor mutable
      Since:
      1.4
      See Also:

    • findAnnotatedFields

      @API(status=MAINTAINED, since="1.4") public static List<Field> findAnnotatedFields(Class<?> clazz, Class<? extends Annotation> annotationType, Predicate<Field> predicate, HierarchyTraversalMode traversalMode)
      Find all fields of the supplied class or interface that are annotated or meta-annotated with the specified annotationType and match the specified predicate, using the supplied hierarchy traversal mode.

      Fields declared in the same class or interface will be ordered using an algorithm that is deterministic but intentionally nonobvious.

      The results will not contain fields that are hidden or synthetic.

      Parameters:
      clazz - the class or interface in which to find the fields; never null
      annotationType - the annotation type to search for; never null
      predicate - the field filter; never null
      traversalMode - the hierarchy traversal mode; never null
      Returns:
      the list of all such fields found; neither null nor mutable
      Since:
      1.4
      See Also:

    • findAnnotatedFieldValues

      @API(status=MAINTAINED, since="1.4") public static List<Object> findAnnotatedFieldValues(Object instance, Class<? extends Annotation> annotationType)
      Find the values of all non-static fields of the supplied instance that are annotated or meta-annotated with the specified annotationType, using top-down search semantics within the type hierarchy.

      Values from fields declared in the same class or interface will be ordered using an algorithm that is deterministic but intentionally nonobvious.

      The results will not contain values from fields that are hidden or synthetic.

      Parameters:
      instance - the instance in which to find the fields; never null
      annotationType - the annotation type to search for; never null
      Returns:
      the list of all such field values found; neither null nor mutable
      Since:
      1.4
      See Also:

    • findAnnotatedFieldValues

      @API(status=MAINTAINED, since="1.4") public static List<Object> findAnnotatedFieldValues(Class<?> clazz, Class<? extends Annotation> annotationType)
      Find the values of all static fields of the supplied class or interface that are annotated or meta-annotated with the specified annotationType, using top-down search semantics within the type hierarchy.

      Values from fields declared in the same class or interface will be ordered using an algorithm that is deterministic but intentionally nonobvious.

      The results will not contain values from fields that are hidden or synthetic.

      Parameters:
      clazz - the class or interface in which to find the fields; never null
      annotationType - the annotation type to search for; never null
      Returns:
      the list of all such field values found; neither null nor mutable
      Since:
      1.4
      See Also:

    • findAnnotatedFieldValues

      @API(status=MAINTAINED, since="1.4") public static <T> List<T> findAnnotatedFieldValues(Object instance, Class<? extends Annotation> annotationType, Class<T> fieldType)
      Find the values of all non-static fields of the supplied instance that are declared to be of the specified fieldType and are annotated or meta-annotated with the specified annotationType, using top-down search semantics within the type hierarchy.

      Values from fields declared in the same class or interface will be ordered using an algorithm that is deterministic but intentionally nonobvious.

      The results will not contain values from fields that are hidden or synthetic.

      Parameters:
      instance - the instance in which to find the fields; never null
      annotationType - the annotation type to search for; never null
      fieldType - the declared type of fields to find; never null
      Returns:
      the list of all such field values found; neither null nor mutable
      Since:
      1.4
      See Also:

    • findAnnotatedFieldValues

      @API(status=MAINTAINED, since="1.4") public static <T> List<T> findAnnotatedFieldValues(Class<?> clazz, Class<? extends Annotation> annotationType, Class<T> fieldType)
      Find the values of all static fields of the supplied class or interface that are declared to be of the specified fieldType and are annotated or meta-annotated with the specified annotationType, using top-down search semantics within the type hierarchy.

      Values from fields declared in the same class or interface will be ordered using an algorithm that is deterministic but intentionally nonobvious.

      The results will not contain values from fields that are hidden or synthetic.

      Parameters:
      clazz - the class or interface in which to find the fields; never null
      annotationType - the annotation type to search for; never null
      fieldType - the declared type of fields to find; never null
      Returns:
      the list of all such field values found; neither null nor mutable
      Since:
      1.4
      See Also:

    • findAnnotatedMethods

      public static List<Method> findAnnotatedMethods(Class<?> clazz, Class<? extends Annotation> annotationType, HierarchyTraversalMode traversalMode)
      Find all methods of the supplied class or interface that are annotated or meta-annotated with the specified annotationType.
      Parameters:
      clazz - the class or interface in which to find the methods; never null
      annotationType - the annotation type to search for; never null
      traversalMode - the hierarchy traversal mode; never null
      Returns:
      the list of all such methods found; neither null nor mutable