Retro68/gcc/libjava/classpath/java/lang/reflect/AnnotatedElement.java

/* AnnotatedElement.java
   Copyright (C) 2004, 2005 Free Software Foundation, Inc.

This file is part of GNU Classpath.

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it under the terms of the GNU General Public License as published by
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02110-1301 USA.

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permission to link this library with independent modules to produce an
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package java.lang.reflect;

import java.lang.annotation.Annotation;

/**
 * <p>
 * Represents an element that can be annotated.  The methods of this interface
 * provide reflection-based access to the annotations associated with a
 * particular element, such as a class, field, method or package.  Each
 * annotation returned by these methods is both immutable and serializable.
 * The returned arrays may be freely modified, without any effect on the
 * arrays returned to future callers.
 * </p>
 * <p>
 * If an annotation refers to a type or enumeration constant that is
 * inaccessible, then a <code>TypeNotPresentException</code> or
 * <code>EnumConstantNotPresentException</code> will be thrown.  Likewise,
 * invalid annotations will produce either a
 * <code>AnnotationTypeMismatchException</code> or
 * <code>IncompleteAnnotationException</code>.
 * </p>
 *
 * @author Tom Tromey (tromey@redhat.com)
 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
 * @since 1.5
 */
public interface AnnotatedElement
{

  /**
   * Returns the element's annotation for the specified annotation type,
   * or <code>null</code> if no such annotation exists.
   *
   * @param annotationClass the type of annotation to look for.
   * @return this element's annotation for the specified type, or
   *         <code>null</code> if no such annotation exists.
   * @throws NullPointerException if the annotation class is <code>null</code>.
   */
  <T extends Annotation> T getAnnotation(Class<T> annotationClass);

  /**
   * Returns all annotations associated with the element.  If there are
   * no annotations associated with the element, then a zero-length array
   * will be returned.  The returned array may be modified by the client
   * code, but this will have no effect on the annotation content of the
   * element, and hence no effect on the return value of this method for
   * future callers.
   *
   * @return this element's annotations.
   */
  Annotation[] getAnnotations();

  /**
   * Returns all annotations directly defined by the element.  If there are
   * no annotations directly associated with the element, then a zero-length
   * array will be returned.  The returned array may be modified by the client
   * code, but this will have no effect on the annotation content of this
   * class, and hence no effect on the return value of this method for
   * future callers.
   *
   * @return the annotations directly defined by the element.
   * @since 1.5
   */
  Annotation[] getDeclaredAnnotations();

  /**
   * Returns true if an annotation for the specified type is associated
   * with the element.  This is primarily a short-hand for using marker
   * annotations.
   *
   * @param annotationClass the type of annotation to look for.
   * @return true if an annotation exists for the specified type.
   * @since 1.5
   */
  boolean isAnnotationPresent(Class<? extends Annotation> annotationClass);

}