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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

 *

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 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

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package java.lang.reflect;

import java.lang.annotation.Annotation;

/**

 * Represents an annotated element of the program currently running in this

 * VM.  This interface allows annotations to be read reflectively.  All

 * annotations returned by methods in this interface are immutable and

 * serializable.  It is permissible for the caller to modify the

 * arrays returned by accessors for array-valued enum members; it will

 * have no affect on the arrays returned to other callers.

 *

 * <p>The {@link #getAnnotationsByType(Class)} and {@link

 * #getDeclaredAnnotationsByType(Class)} methods support multiple

 * annotations of the same type on an element. If the argument to either method

 * is a repeatable annotation type (JLS 9.6), then the method will "look

 * through" a container annotation (JLS 9.7) which was generated at

 * compile-time to wrap multiple annotations of the argument type.

 *

 * <p>The terms <em>directly present</em> and <em>present</em> are used

 * throughout this interface to describe precisely which annotations are

 * returned by methods:

 *

 * <ul>

 * <li>An annotation A is <em>directly present</em> on an element E if E is

 * associated with a RuntimeVisibleAnnotations or

 * RuntimeVisibleParameterAnnotations attribute, and:

 *

 * <ul>

 * <li>for an invocation of {@code get[Declared]Annotation(Class<T>)} or

 * {@code get[Declared]Annotations()}, the attribute contains A.

 *

 * <li>for an invocation of {@code get[Declared]AnnotationsByType(Class<T>)}, the

 * attribute either contains A or, if the type of A is repeatable, contains

 * exactly one annotation whose value element contains A and whose type is the

 * containing annotation type of A's type (JLS 9.6).

 * </ul>

 *

 * <p>

 * <li>An annotation A is <em>present</em> on an element E if either:

 *

 * <ul>

 * <li>A is <em>directly present</em> on E; or

 *

 * <li>A is not <em>directly present</em> on E, and E is a class, and A's type

 * is inheritable (JLS 9.6.3.3), and A is <em>present</em> on the superclass of

 * E.

 * </ul>

 *

 * </ul>

 *

 * <p>If an annotation returned by a method in this interface contains

 * (directly or indirectly) a {@link Class}-valued member referring to

 * a class that is not accessible in this VM, attempting to read the class

 * by calling the relevant Class-returning method on the returned annotation

 * will result in a {@link TypeNotPresentException}.

 *

 * <p>Similarly, attempting to read an enum-valued member will result in

 * a {@link EnumConstantNotPresentException} if the enum constant in the

 * annotation is no longer present in the enum type.

 *

 * <p>Attempting to read annotations of a repeatable annotation type T

 * that are contained in an annotation whose type is not, in fact, the

 *

 * <p>Finally, attempting to read a member whose definition has evolved

 * incompatibly will result in a {@link

 * java.lang.annotation.AnnotationTypeMismatchException} or an

 * {@link java.lang.annotation.IncompleteAnnotationException}.

 *

 * @see java.lang.EnumConstantNotPresentException

 * @see java.lang.TypeNotPresentException

 * @see java.lang.annotation.AnnotationTypeMismatchException

 * @see java.lang.annotation.IncompleteAnnotationException

 * @since 1.5

 * @author Josh Bloch

 */

public interface AnnotatedElement {

    /**

     * Returns true if an annotation for the specified type

     * is present on this element, else false.  This method

     * is designed primarily for convenient access to marker annotations.

     *

     * <p>The truth value returned by this method is equivalent to:

     * {@code getAnnotation(annotationClass) != null}

     *

     * <p>The body of the default method is specified to be the code

     * above.

     *

     * @param annotationClass the Class object corresponding to the

     *        annotation type

     * @return true if an annotation for the specified annotation

     *     type is present on this element, else false

     * @throws NullPointerException if the given annotation class is null

     * @since 1.5

     */

    default boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) {

        return getAnnotation(annotationClass) != null;

    }

   /**

     * Returns this element's annotation for the specified type if

     * such an annotation is present, else null.

     *

     * @param annotationClass the Class object corresponding to the

     *        annotation type

     * @return this element's annotation for the specified annotation type if

     *     present on this element, else null

     * @throws NullPointerException if the given annotation class is null

     * @since 1.5

     */

    <T extends Annotation> T getAnnotation(Class<T> annotationClass);

    /**

     * Returns annotations that are <em>present</em> on this element.

     *

     * If there are no annotations <em>present</em> on this element, the return

     * value is an array of length 0.

     *

     * The difference between this method and {@link #getAnnotation(Class)}

     * is that this method detects if its argument is a <em>repeatable

     * annotation type</em> (JLS 9.6), and if so, attempts to find one or

     * more annotations of that type by "looking through" a container

     * annotation.

     *

     * The caller of this method is free to modify the returned array; it will

     * have no effect on the arrays returned to other callers.

     *

     * @param annotationClass the Class object corresponding to the

     *        annotation type

     * @return all this element's annotations for the specified annotation type if

     *     present on this element, else an array of length zero

     * @throws NullPointerException if the given annotation class is null

     * @since 1.8

     */

    <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass);

    /**

     * Returns annotations that are <em>present</em> on this element.

     *

     * If there are no annotations <em>present</em> on this element, the return

     * value is an array of length 0.

     *

     * The caller of this method is free to modify the returned array; it will

     * have no effect on the arrays returned to other callers.

     *

     * @return annotations present on this element

     * @since 1.5

     */

    Annotation[] getAnnotations();

    /**

     * Returns this element's annotation for the specified type if

     * such an annotation is present, else null.

     *

     * This method ignores inherited annotations. (Returns null if no

     * annotations are directly present on this element.)

     *

     * @param annotationClass the Class object corresponding to the

     *        annotation type

     * @return this element's annotation for the specified annotation type if

     *     present on this element, else null

     * @throws NullPointerException if the given annotation class is null

     * @since 1.8

     */

    <T extends Annotation> T getDeclaredAnnotation(Class<T> annotationClass);

    /**

     * Returns annotations that are <em>directly present</em> on this element.

     * This method ignores inherited annotations.

     *

     * If there are no annotations <em>directly present</em> on this element,

     * the return value is an array of length 0.

     *

     * The difference between this method and {@link

     * #getDeclaredAnnotation(Class)} is that this method detects if its

     * argument is a <em>repeatable annotation type</em> (JLS 9.6), and if so,

     * attempts to find one or more annotations of that type by "looking

     * through" a container annotation.

     *

     * The caller of this method is free to modify the returned array; it will

     * have no effect on the arrays returned to other callers.

     *

     * @param annotationClass the Class object corresponding to the

     *        annotation type

     * @return all this element's annotations for the specified annotation type if

     *     present on this element, else an array of length zero

     * @throws NullPointerException if the given annotation class is null

     * @since 1.8

     */

    <T extends Annotation> T[] getDeclaredAnnotationsByType(Class<T> annotationClass);

    /**

     * Returns annotations that are <em>directly present</em> on this element.

     * This method ignores inherited annotations.

     *

     * If there are no annotations <em>directly present</em> on this element,

     * the return value is an array of length 0.

     *

     * The caller of this method is free to modify the returned array; it will

     * have no effect on the arrays returned to other callers.

     *

     * @return annotations directly present on this element

     * @since 1.5

     */

    Annotation[] getDeclaredAnnotations();

}