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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 not define
an annotation type. Also note that this interface does not itself
define an annotation type.
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.
*
* @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
* <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:
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 <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:
@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.
*/
Class<? extends Annotation> annotationType();
}