/*
* Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package java.lang.annotation;
/**
* The common interface extended by all annotation types. Note that an
* interface that manually extends this one does <i>not</i> define
* an annotation type. Also note that this interface does not itself
* define an annotation type.
*
* @author Josh Bloch
* @since 1.5
*/
public interface Annotation {
/**
* Returns true if the specified object represents an annotation
* that is logically equivalent to this one. In other words,
* returns true if the specified object is an instance of the same
* annotation type as this instance, all of whose members are equal
* to the corresponding member of this annotation, as defined below:
* <ul>
* <li>Two corresponding primitive typed members whose values are
* <tt>x</tt> and <tt>y</tt> are considered equal if <tt>x == y</tt>,
* unless their type is <tt>float</tt> or <tt>double</tt>.
*
* <li>Two corresponding <tt>float</tt> members whose values
* are <tt>x</tt> and <tt>y</tt> are considered equal if
* <tt>Float.valueOf(x).equals(Float.valueOf(y))</tt>.
* (Unlike the <tt>==</tt> operator, NaN is considered equal
* to itself, and <tt>0.0f</tt> unequal to <tt>-0.0f</tt>.)
*
* <li>Two corresponding <tt>double</tt> members whose values
* are <tt>x</tt> and <tt>y</tt> are considered equal if
* <tt>Double.valueOf(x).equals(Double.valueOf(y))</tt>.
* (Unlike the <tt>==</tt> operator, NaN is considered equal
* to itself, and <tt>0.0</tt> unequal to <tt>-0.0</tt>.)
*
* <li>Two corresponding <tt>String</tt>, <tt>Class</tt>, enum, or
* annotation typed members whose values are <tt>x</tt> and <tt>y</tt>
* are considered equal if <tt>x.equals(y)</tt>. (Note that this
* definition is recursive for annotation typed members.)
*
* <li>Two corresponding array typed members <tt>x</tt> and <tt>y</tt>
* are considered equal if <tt>Arrays.equals(x, y)</tt>, for the
* appropriate overloading of {@link java.util.Arrays#equals}.
* </ul>
*
* @return true if the specified object represents an annotation
* that is logically equivalent to this one, otherwise false
*/
boolean equals(Object obj);
/**
* Returns the hash code of this annotation, as defined below:
*
* <p>The hash code of an annotation is the sum of the hash codes
* of its members (including those with default values), as defined
* below:
*
* The hash code of an annotation member is (127 times the hash code
* of the member-name as computed by {@link String#hashCode()}) XOR
* the hash code of the member-value, as defined below:
*
* <p>The hash code of a member-value depends on its type:
* <ul>
* <li>The hash code of a primitive value <tt><i>v</i></tt> is equal to
* <tt><i>WrapperType</i>.valueOf(<i>v</i>).hashCode()</tt>, where
* <tt><i>WrapperType</i></tt> is the wrapper type corresponding
* to the primitive type of <tt><i>v</i></tt> ({@link Byte},
* {@link Character}, {@link Double}, {@link Float}, {@link Integer},
* {@link Long}, {@link Short}, or {@link Boolean}).
*
* <li>The hash code of a string, enum, class, or annotation member-value
I <tt><i>v</i></tt> is computed as by calling
* <tt><i>v</i>.hashCode()</tt>. (In the case of annotation
* member values, this is a recursive definition.)
*
* <li>The hash code of an array member-value is computed by calling
* the appropriate overloading of
* {@link java.util.Arrays#hashCode(long[]) Arrays.hashCode}
* on the value. (There is one overloading for each primitive
* type, and one for object reference types.)
* </ul>
*
* @return the hash code of this annotation
*/
int hashCode();
/**
* Returns a string representation of this annotation. The details
* of the representation are implementation-dependent, but the following
* may be regarded as typical:
* <pre>
* @com.acme.util.Name(first=Alfred, middle=E., last=Neuman)
* </pre>
*
* @return a string representation of this annotation
*/
String toString();
/**
* Returns the annotation type of this annotation.
*/
Class<? extends Annotation> annotationType();
}