Annotation

public interface Annotation

Known Indirect Subclasses Deprecated, Documented, FunctionalInterface, Inherited, Native, Override, Repeatable, Retention, SafeVarargs, SuppressWarnings, Target Deprecated A program element annotated @Deprecated is one that programmers are discouraged from using, typically because it is dangerous, or because a better alternative exists.  Documented Indicates that annotations with a type are to be documented by javadoc and similar tools by default.  FunctionalInterface An informative annotation type used to indicate that an interface type declaration is intended to be a functional interface as defined by the Java Language Specification.  Inherited Indicates that an annotation type is automatically inherited.  Native Indicates that a field defining a constant value may be referenced from native code.  Override Indicates that a method declaration is intended to override a method declaration in a supertype.  Repeatable The annotation type java.lang.annotation.Repeatable is used to indicate that the annotation type whose declaration it (meta-)annotates is repeatable.  Retention Indicates how long annotations with the annotated type are to be retained.  SafeVarargs A programmer assertion that the body of the annotated method or constructor does not perform potentially unsafe operations on its varargs parameter.  SuppressWarnings Indicates that the named compiler warnings should be suppressed in the annotated element (and in all program elements contained in the annotated element).  Target Indicates the contexts in which an annotation type is applicable.

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.

Public Method Summary

abstract Class<? extends Annotation>	annotationType() Returns the annotation type of this annotation.
abstract boolean	equals(Object obj) Returns true if the specified object represents an annotation that is logically equivalent to this one.
abstract int	hashCode() 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).
abstract String	toString() Returns a string representation of this annotation.

Public Methods

public abstract Class<? extends Annotation> annotationType ()

Returns the annotation type of this annotation.

Returns

• the annotation type of this annotation

public abstract boolean equals (Object obj)

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 Arrays.equals(boolean[], boolean[]).

Parameters

obj	the object to compare this instance with.

Returns

• true if the specified object represents an annotation that is logically equivalent to this one, otherwise false

public abstract int hashCode ()

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

public abstract String toString ()

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