jaroslav@66: /*
jaroslav@66:  * Copyright (c) 2003, 2009, Oracle and/or its affiliates. All rights reserved.
jaroslav@66:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
jaroslav@66:  *
jaroslav@66:  * This code is free software; you can redistribute it and/or modify it
jaroslav@66:  * under the terms of the GNU General Public License version 2 only, as
jaroslav@66:  * published by the Free Software Foundation.  Oracle designates this
jaroslav@66:  * particular file as subject to the "Classpath" exception as provided
jaroslav@66:  * by Oracle in the LICENSE file that accompanied this code.
jaroslav@66:  *
jaroslav@66:  * This code is distributed in the hope that it will be useful, but WITHOUT
jaroslav@66:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
jaroslav@66:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
jaroslav@66:  * version 2 for more details (a copy is included in the LICENSE file that
jaroslav@66:  * accompanied this code).
jaroslav@66:  *
jaroslav@66:  * You should have received a copy of the GNU General Public License version
jaroslav@66:  * 2 along with this work; if not, write to the Free Software Foundation,
jaroslav@66:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
jaroslav@66:  *
jaroslav@66:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
jaroslav@66:  * or visit www.oracle.com if you need additional information or have any
jaroslav@66:  * questions.
jaroslav@66:  */
jaroslav@66: 
jaroslav@66: package java.lang.annotation;
jaroslav@66: 
jaroslav@66: /**
jaroslav@66:  * The common interface extended by all annotation types.  Note that an
jaroslav@66:  * interface that manually extends this one does <i>not</i> define
jaroslav@66:  * an annotation type.  Also note that this interface does not itself
jaroslav@66:  * define an annotation type.
jaroslav@66:  *
jaroslav@66:  * More information about annotation types can be found in section 9.6 of
jaroslav@66:  * <cite>The Java&trade; Language Specification</cite>.
jaroslav@66:  *
jaroslav@66:  * @author  Josh Bloch
jaroslav@66:  * @since   1.5
jaroslav@66:  */
jaroslav@66: public interface Annotation {
jaroslav@66:     /**
jaroslav@66:      * Returns true if the specified object represents an annotation
jaroslav@66:      * that is logically equivalent to this one.  In other words,
jaroslav@66:      * returns true if the specified object is an instance of the same
jaroslav@66:      * annotation type as this instance, all of whose members are equal
jaroslav@66:      * to the corresponding member of this annotation, as defined below:
jaroslav@66:      * <ul>
jaroslav@66:      *    <li>Two corresponding primitive typed members whose values are
jaroslav@66:      *    <tt>x</tt> and <tt>y</tt> are considered equal if <tt>x == y</tt>,
jaroslav@66:      *    unless their type is <tt>float</tt> or <tt>double</tt>.
jaroslav@66:      *
jaroslav@66:      *    <li>Two corresponding <tt>float</tt> members whose values
jaroslav@66:      *    are <tt>x</tt> and <tt>y</tt> are considered equal if
jaroslav@66:      *    <tt>Float.valueOf(x).equals(Float.valueOf(y))</tt>.
jaroslav@66:      *    (Unlike the <tt>==</tt> operator, NaN is considered equal
jaroslav@66:      *    to itself, and <tt>0.0f</tt> unequal to <tt>-0.0f</tt>.)
jaroslav@66:      *
jaroslav@66:      *    <li>Two corresponding <tt>double</tt> members whose values
jaroslav@66:      *    are <tt>x</tt> and <tt>y</tt> are considered equal if
jaroslav@66:      *    <tt>Double.valueOf(x).equals(Double.valueOf(y))</tt>.
jaroslav@66:      *    (Unlike the <tt>==</tt> operator, NaN is considered equal
jaroslav@66:      *    to itself, and <tt>0.0</tt> unequal to <tt>-0.0</tt>.)
jaroslav@66:      *
jaroslav@66:      *    <li>Two corresponding <tt>String</tt>, <tt>Class</tt>, enum, or
jaroslav@66:      *    annotation typed members whose values are <tt>x</tt> and <tt>y</tt>
jaroslav@66:      *    are considered equal if <tt>x.equals(y)</tt>.  (Note that this
jaroslav@66:      *    definition is recursive for annotation typed members.)
jaroslav@66:      *
jaroslav@66:      *    <li>Two corresponding array typed members <tt>x</tt> and <tt>y</tt>
jaroslav@66:      *    are considered equal if <tt>Arrays.equals(x, y)</tt>, for the
jaroslav@66:      *    appropriate overloading of {@link java.util.Arrays#equals}.
jaroslav@66:      * </ul>
jaroslav@66:      *
jaroslav@66:      * @return true if the specified object represents an annotation
jaroslav@66:      *     that is logically equivalent to this one, otherwise false
jaroslav@66:      */
jaroslav@66:     boolean equals(Object obj);
jaroslav@66: 
jaroslav@66:     /**
jaroslav@66:      * Returns the hash code of this annotation, as defined below:
jaroslav@66:      *
jaroslav@66:      * <p>The hash code of an annotation is the sum of the hash codes
jaroslav@66:      * of its members (including those with default values), as defined
jaroslav@66:      * below:
jaroslav@66:      *
jaroslav@66:      * The hash code of an annotation member is (127 times the hash code
jaroslav@66:      * of the member-name as computed by {@link String#hashCode()}) XOR
jaroslav@66:      * the hash code of the member-value, as defined below:
jaroslav@66:      *
jaroslav@66:      * <p>The hash code of a member-value depends on its type:
jaroslav@66:      * <ul>
jaroslav@66:      * <li>The hash code of a primitive value <tt><i>v</i></tt> is equal to
jaroslav@66:      *     <tt><i>WrapperType</i>.valueOf(<i>v</i>).hashCode()</tt>, where
jaroslav@66:      *     <tt><i>WrapperType</i></tt> is the wrapper type corresponding
jaroslav@66:      *     to the primitive type of <tt><i>v</i></tt> ({@link Byte},
jaroslav@66:      *     {@link Character}, {@link Double}, {@link Float}, {@link Integer},
jaroslav@66:      *     {@link Long}, {@link Short}, or {@link Boolean}).
jaroslav@66:      *
jaroslav@66:      * <li>The hash code of a string, enum, class, or annotation member-value
jaroslav@66:      I     <tt><i>v</i></tt> is computed as by calling
jaroslav@66:      *     <tt><i>v</i>.hashCode()</tt>.  (In the case of annotation
jaroslav@66:      *     member values, this is a recursive definition.)
jaroslav@66:      *
jaroslav@66:      * <li>The hash code of an array member-value is computed by calling
jaroslav@66:      *     the appropriate overloading of
jaroslav@66:      *     {@link java.util.Arrays#hashCode(long[]) Arrays.hashCode}
jaroslav@66:      *     on the value.  (There is one overloading for each primitive
jaroslav@66:      *     type, and one for object reference types.)
jaroslav@66:      * </ul>
jaroslav@66:      *
jaroslav@66:      * @return the hash code of this annotation
jaroslav@66:      */
jaroslav@66:     int hashCode();
jaroslav@66: 
jaroslav@66:     /**
jaroslav@66:      * Returns a string representation of this annotation.  The details
jaroslav@66:      * of the representation are implementation-dependent, but the following
jaroslav@66:      * may be regarded as typical:
jaroslav@66:      * <pre>
jaroslav@66:      *   &#064;com.acme.util.Name(first=Alfred, middle=E., last=Neuman)
jaroslav@66:      * </pre>
jaroslav@66:      *
jaroslav@66:      * @return a string representation of this annotation
jaroslav@66:      */
jaroslav@66:     String toString();
jaroslav@66: 
jaroslav@66:     /**
jaroslav@66:      * Returns the annotation type of this annotation.
jaroslav@66:      */
jaroslav@66:     Class<? extends Annotation> annotationType();
jaroslav@66: }