java.lang

Class Enum<E extends Enum<E>>

java.lang.Object

java.lang.Enum<E>

Type Parameters:

E - The enum type subclass

All Implemented Interfaces:

Serializable, Comparable<E>

public abstract class Enum<E extends Enum<E>>
extends Object
implements Comparable<E>, Serializable

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.

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Enum(String name, int ordinal) Sole constructor.

Method Summary

Modifier and Type	Method and Description
int	compareTo(E o) Compares this enum with the specified object for order.
boolean	equals(Object other) Returns true if the specified object is equal to this enum constant.
int	hashCode() Returns a hash code for this enum constant.
String	name() Returns the name of this enum constant, exactly as declared in its enum declaration.
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) This method is available for compilation purpose.

Methods inherited from class java.lang.Object

clone, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Enum

protected 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 - - The name of this enum constant, which is the identifier used to declare it.

ordinal - - The ordinal of this enumeration constant (its position in the enum declaration, where the initial constant is assigned an ordinal of zero).

Method Detail

compareTo

public final 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.

Specified by:

compareTo in interface Comparable<E extends Enum<E>>

Parameters:

o - the object to be compared.

Returns:

a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

equals

public final boolean equals(@Nullable
                            Object other)

Returns true if the specified object is equal to this enum constant.

Overrides:

equals in class Object

Parameters:

other - the object to be compared for equality with this object.

Returns:

true if the specified object is equal to this enum constant.

See Also:

Object.hashCode(), HashMap

hashCode

public final int hashCode()

Returns a hash code for this enum constant.

Overrides:

hashCode in class Object

Returns:

a hash code for this enum constant.

See Also:

Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

name

public final 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:

the name of this enum constant

ordinal

public 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).

Returns:

the ordinal of this enumeration constant

toString

public 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.

Overrides:

toString in class Object

Returns:

the name of this enum constant

valueOf

public static <T extends Enum<T>> T valueOf(Class<T> enumType,
                                            String name)

This method is available for compilation purpose.

Type Parameters:

T - the enum type whose constant is to be returned

Parameters:

enumType - the Class object of the enum type from which to return a constant

name - the name of the constant to return

Returns:

the enum constant of the specified enum type with the specified name

Throws:

NoSuchMethodError - always