public
abstract
class
Enum
extends Object
implements
Comparable<E extends Enum<E>>,
Serializable
| java.lang.Object | |
| ↳ | java.lang.Enum<E extends java.lang.Enum<E>> |
 Known Direct Subclasses
|
This is the common base class of all Java language enumeration types. More information about enums, including descriptions of the implicitly declared methods synthesized by the compiler, can be found in section 8.9 of The Java™ Language Specification.
Note that when using an enumeration type as the type of a set or as the type of the keys in a map, specialized and efficient set and map implementations are available.
See also:
Protected constructors | |
|---|---|
Enum(String name, int ordinal)
Sole constructor. |
|
Public methods | |
|---|---|
final
int
|
compareTo(E o)
Compares this enum with the specified object for order. |
final
boolean
|
equals(Object other)
Returns true if the specified object is equal to this enum constant. |
final
Class<E>
|
getDeclaringClass()
Returns the Class object corresponding to this enum constant's enum type. |
final
int
|
hashCode()
Returns a hash code for this enum constant. |
final
String
|
name()
Returns the name of this enum constant, exactly as declared in its enum declaration. |
final
int
|
ordinal()
Returns the ordinal of this enumeration constant (its position in its enum declaration, where the initial constant is assigned an ordinal of zero). |
String
|
toString()
Returns the name of this enum constant, as contained in the declaration. |
static
<T extends Enum<T>>
T
|
valueOf(Class<T> enumType, String name)
Returns the enum constant of the specified enum type with the specified name. |
Protected methods | |
|---|---|
final
Object
|
clone()
Throws CloneNotSupportedException. |
final
void
|
finalize()
enum classes cannot have finalize methods. |
Inherited methods | |
|---|---|
From
class
java.lang.Object
| |
From
interface
java.lang.Comparable
| |
Enum (String name, int ordinal)
Sole constructor. Programmers cannot invoke this constructor. It is for use by code emitted by the compiler in response to enum type declarations.
| Parameters | |
|---|---|
name |
String:
- The name of this enum constant, which is the identifier
used to declare it. |
ordinal |
int:
- The ordinal of this enumeration constant (its position
in the enum declaration, where the initial constant is assigned
an ordinal of zero).
|
int compareTo (E o)
Compares this enum with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object. Enum constants are only comparable to other enum constants of the same enum type. The natural order implemented by this method is the order in which the constants are declared.
| Parameters | |
|---|---|
o |
E
|
| Returns | |
|---|---|
int |
|
boolean equals (Object other)
Returns true if the specified object is equal to this enum constant.
| Parameters | |
|---|---|
other |
Object:
the object to be compared for equality with this object. |
| Returns | |
|---|---|
boolean |
true if the specified object is equal to this enum constant. |
Class<E> getDeclaringClass ()
Returns the Class object corresponding to this enum constant's
enum type. Two enum constants e1 and e2 are of the
same enum type if and only if
e1.getDeclaringClass() == e2.getDeclaringClass().
(The value returned by this method may differ from the one returned
by the getClass() method for enum constants with
constant-specific class bodies.)
| Returns | |
|---|---|
Class<E> |
the Class object corresponding to this enum constant's enum type |
int hashCode ()
Returns a hash code for this enum constant.
| Returns | |
|---|---|
int |
a hash code for this enum constant. |
String name ()
Returns the name of this enum constant, exactly as declared in its
enum declaration.
Most programmers should use the toString() method in
preference to this one, as the toString method may return
a more user-friendly name. This method is designed primarily for
use in specialized situations where correctness depends on getting the
exact name, which will not vary from release to release.
| Returns | |
|---|---|
String |
the name of this enum constant |
int ordinal ()
Returns the ordinal of this enumeration constant (its position
in its enum declaration, where the initial constant is assigned
an ordinal of zero).
Most programmers will have no use for this method. It is
designed for use by sophisticated enum-based data structures, such
as EnumSet and EnumMap.
| Returns | |
|---|---|
int |
the ordinal of this enumeration constant |
String toString ()
Returns the name of this enum constant, as contained in the declaration. This method may be overridden, though it typically isn't necessary or desirable. An enum type should override this method when a more "programmer-friendly" string form exists.
| Returns | |
|---|---|
String |
the name of this enum constant |
T valueOf (Class<T> enumType, String name)
Returns the enum constant of the specified enum type with the specified name. The name must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
Note that for a particular enum type T, the
implicitly declared public static T valueOf(String)
method on that enum may be used instead of this method to map
from a name to the corresponding enum constant. All the
constants of an enum type can be obtained by calling the
implicit public static T[] values() method of that
type.
| Parameters | |
|---|---|
enumType |
Class:
the Class object of the enum type from which
to return a constant |
name |
String:
the name of the constant to return |
| Returns | |
|---|---|
T |
the enum constant of the specified enum type with the specified name |
| Throws | |
|---|---|
IllegalArgumentException |
if the specified enum type has no constant with the specified name, or the specified class object does not represent an enum type |
NullPointerException |
if enumType or name
is null |
Object clone ()
Throws CloneNotSupportedException. This guarantees that enums are never cloned, which is necessary to preserve their "singleton" status.
| Returns | |
|---|---|
Object |
(never returns) |
| Throws | |
|---|---|
CloneNotSupportedException |
|
Developers