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   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   * This code is free software; you can redistribute it and/or modify it
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   * published by the Free Software Foundation.  Oracle designates this
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   *
   * 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).
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   * You should have received a copy of the GNU General Public License version
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  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.
   *
   * More information about annotation types can be found in section 9.6 of
   * <cite>The Java&trade; 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:
       * <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>
       *   &#064;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.
       * @return the annotation type of this annotation
       */
      Class<? extends Annotation> annotationType();
  }
  