001/* AnnotatedElement.java
002   Copyright (C) 2004, 2005 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package java.lang.reflect;
040
041import java.lang.annotation.Annotation;
042
043/**
044 * <p>
045 * Represents an element that can be annotated.  The methods of this interface
046 * provide reflection-based access to the annotations associated with a
047 * particular element, such as a class, field, method or package.  Each
048 * annotation returned by these methods is both immutable and serializable.
049 * The returned arrays may be freely modified, without any effect on the
050 * arrays returned to future callers.
051 * </p>
052 * <p>
053 * If an annotation refers to a type or enumeration constant that is
054 * inaccessible, then a <code>TypeNotPresentException</code> or
055 * <code>EnumConstantNotPresentException</code> will be thrown.  Likewise,
056 * invalid annotations will produce either a
057 * <code>AnnotationTypeMismatchException</code> or
058 * <code>IncompleteAnnotationException</code>.
059 * </p>
060 *
061 * @author Tom Tromey (tromey@redhat.com)
062 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
063 * @since 1.5
064 */
065public interface AnnotatedElement
066{
067
068  /**
069   * Returns the element's annotation for the specified annotation type,
070   * or <code>null</code> if no such annotation exists.
071   *
072   * @param annotationClass the type of annotation to look for.
073   * @return this element's annotation for the specified type, or
074   *         <code>null</code> if no such annotation exists.
075   * @throws NullPointerException if the annotation class is <code>null</code>.
076   */
077  <T extends Annotation> T getAnnotation(Class<T> annotationClass);
078
079  /**
080   * Returns all annotations associated with the element.  If there are
081   * no annotations associated with the element, then a zero-length array
082   * will be returned.  The returned array may be modified by the client
083   * code, but this will have no effect on the annotation content of the
084   * element, and hence no effect on the return value of this method for
085   * future callers.
086   *
087   * @return this element's annotations.
088   */
089  Annotation[] getAnnotations();
090
091  /**
092   * Returns all annotations directly defined by the element.  If there are
093   * no annotations directly associated with the element, then a zero-length
094   * array will be returned.  The returned array may be modified by the client
095   * code, but this will have no effect on the annotation content of this
096   * class, and hence no effect on the return value of this method for
097   * future callers.
098   *
099   * @return the annotations directly defined by the element.
100   * @since 1.5
101   */
102  Annotation[] getDeclaredAnnotations();
103
104  /**
105   * Returns true if an annotation for the specified type is associated
106   * with the element.  This is primarily a short-hand for using marker
107   * annotations.
108   *
109   * @param annotationClass the type of annotation to look for.
110   * @return true if an annotation exists for the specified type.
111   * @since 1.5
112   */
113  boolean isAnnotationPresent(Class<? extends Annotation> annotationClass);
114
115}