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/* * @(#)Annotation.java 1.10 05/11/17 * * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ 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(); }