/*
* Copyright (c) 2003, 2013, Oracle and/or its affiliates. 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.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 not define
an annotation type. Also note that this interface does not itself
define an annotation type.
More information about annotation types can be found in section 9.6 of
The Java™ Language Specification. The AnnotatedElement interface discusses compatibility concerns when evolving an annotation type from being non-repeatable to being repeatable. Author: Josh Bloch Since: 1.5
/**
* 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.
*
* More information about annotation types can be found in section 9.6 of
* <cite>The Java™ Language Specification</cite>.
*
* The {@link java.lang.reflect.AnnotatedElement} interface discusses
* compatibility concerns when evolving an annotation type from being
* non-repeatable to being repeatable.
*
* @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:
- Two corresponding primitive typed members whose values are
x and y are considered equal if x == y, unless their type is float or double. - Two corresponding
float members whose values are x and y are considered equal if Float.valueOf(x).equals(Float.valueOf(y)). (Unlike the == operator, NaN is considered equal to itself, and 0.0f unequal to -0.0f.) - Two corresponding
double members whose values are x and y are considered equal if Double.valueOf(x).equals(Double.valueOf(y)). (Unlike the == operator, NaN is considered equal to itself, and 0.0 unequal to -0.0.) - Two corresponding
String, Class, enum, or annotation typed members whose values are x and y are considered equal if x.equals(y). (Note that this definition is recursive for annotation typed members.) - Two corresponding array typed members
x and y are considered equal if Arrays.equals(x, y), for the appropriate overloading of Object.equals.
Returns: true if the specified object represents an annotation
that is logically equivalent to this one, otherwise false
/**
* 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
* {@code x} and {@code y} are considered equal if {@code x == y},
* unless their type is {@code float} or {@code double}.
*
* <li>Two corresponding {@code float} members whose values
* are {@code x} and {@code y} are considered equal if
* {@code Float.valueOf(x).equals(Float.valueOf(y))}.
* (Unlike the {@code ==} operator, NaN is considered equal
* to itself, and {@code 0.0f} unequal to {@code -0.0f}.)
*
* <li>Two corresponding {@code double} members whose values
* are {@code x} and {@code y} are considered equal if
* {@code Double.valueOf(x).equals(Double.valueOf(y))}.
* (Unlike the {@code ==} operator, NaN is considered equal
* to itself, and {@code 0.0} unequal to {@code -0.0}.)
*
* <li>Two corresponding {@code String}, {@code Class}, enum, or
* annotation typed members whose values are {@code x} and {@code y}
* are considered equal if {@code x.equals(y)}. (Note that this
* definition is recursive for annotation typed members.)
*
* <li>Two corresponding array typed members {@code x} and {@code y}
* are considered equal if {@code Arrays.equals(x, y)}, 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:
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 String.hashCode()) XOR the hash code of the member-value, as defined below:
The hash code of a member-value depends on its type:
- The hash code of a primitive value
v is equal to
WrapperType.valueOf(v).hashCode(), where
WrapperType is the wrapper type corresponding
to the primitive type of v (Byte, Character, Double, Float, Integer, Long, Short, or Boolean). - The hash code of a string, enum, class, or annotation member-value
I
v is computed as by calling
v.hashCode(). (In the case of annotation
member values, this is a recursive definition.)
- The hash code of an array member-value is computed by calling the appropriate overloading of
Arrays.hashCode on the value. (There is one overloading for each primitive type, and one for object reference types.)
Returns: the hash code of this annotation
/**
* 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 <i>{@code v}</i> is equal to
* <code><i>WrapperType</i>.valueOf(<i>v</i>).hashCode()</code>, where
* <i>{@code WrapperType}</i> is the wrapper type corresponding
* to the primitive type of <i>{@code v}</i> ({@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 <i>{@code v}</i> is computed as by calling
* <code><i>v</i>.hashCode()</code>. (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:
@com.acme.util.Name(first=Alfred, middle=E., last=Neuman)
Returns: a string representation of this annotation
/**
* 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.
Returns: the annotation type of this annotation
/**
* Returns the annotation type of this annotation.
* @return the annotation type of this annotation
*/
Class<? extends Annotation> annotationType();
}