java.lang

Class Enum<E extends Enum<E>>

java.lang.Object

java.lang.Enum<E>

All Implemented Interfaces:

Serializable, Comparable<E>

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

The superclass of all enumerated types. Actual enumeration types inherit from this class, but extending this class does not make a class an enumeration type, since the compiler needs to generate special information for it.

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Enum(String name, int ordinal) Constructor for constants of enum subtypes.

Method Summary

Modifier and Type	Method and Description
protected Object	clone() Enum objects are singletons, they may not be cloned.
int	compareTo(E o) Compares this object to the specified enum object to determine their relative order.
boolean	equals(Object other) Compares this object with the specified object and indicates if they are equal.
protected void	finalize() Enum types may not have finalizers.
Class<E>	getDeclaringClass() Returns the enum constant's declaring class.
static <T extends Enum<T>> T[]	getSharedConstants(Class<T> enumType) Returns a shared, mutable array containing the constants of this enum.
int	hashCode() Returns an integer hash code for this object.
String	name() Returns the name of this enum constant.
int	ordinal() Returns the position of the enum constant in the declaration.
String	toString() Returns a string containing a concise, human-readable description of this object.
static <T extends Enum<T>> T	valueOf(Class<T> enumType, String name) Returns the constant with the specified name of the specified enum type.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Enum

protected Enum(String name,
               int ordinal)

Constructor for constants of enum subtypes.

Parameters:

name - the enum constant's declared name.

ordinal - the enum constant's ordinal, which corresponds to its position in the enum declaration, starting at zero.

Method Detail

name

public final String name()

Returns the name of this enum constant. The name is the field as it appears in the enum declaration.

Returns:

the name of this enum constant.

See Also:

toString()

ordinal

public final int ordinal()

Returns the position of the enum constant in the declaration. The first constant has an ordinal value of zero.

Returns:

the ordinal value of this enum constant.

toString

public String toString()

Returns a string containing a concise, human-readable description of this object. In this case, the enum constant's name is returned.

Overrides:

toString in class Object

Returns:

a printable representation of this object.

equals

public final boolean equals(Object other)

Compares this object with the specified object and indicates if they are equal. In order to be equal, object must be identical to this enum constant.

Overrides:

equals in class Object

Parameters:

other - the object to compare this enum constant with.

Returns:

true if the specified object is equal to this Enum; false otherwise.

See Also:

Object.hashCode()

hashCode

public final int hashCode()

Description copied from class: Object

Returns an integer hash code for this object. By contract, any two objects for which Object.equals(java.lang.Object) returns true must return the same hash code value. This means that subclasses of Object usually override both methods or neither method.

Note that hash values must not change over time unless information used in equals comparisons also changes.

See Writing a correct hashCode method if you intend implementing your own hashCode method.

Overrides:

hashCode in class Object

Returns:

this object's hash code.

See Also:

Object.equals(java.lang.Object)

clone

protected final Object clone()
                      throws CloneNotSupportedException

Enum objects are singletons, they may not be cloned. This method always throws a CloneNotSupportedException.

Overrides:

clone in class Object

Returns:

does not return.

Throws:

CloneNotSupportedException - is always thrown.

compareTo

public final int compareTo(E o)

Compares this object to the specified enum object to determine their relative order. This method compares the object's ordinal values, that is, their position in the enum declaration.

Specified by:

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

Parameters:

o - the enum object to compare this object to.

Returns:

a negative value if the ordinal value of this enum constant is less than the ordinal value of o; 0 if the ordinal values of this enum constant and o are equal; a positive value if the ordinal value of this enum constant is greater than the ordinal value of o.

See Also:

Comparable

getDeclaringClass

public final Class<E> getDeclaringClass()

Returns the enum constant's declaring class.

Returns:

the class object representing the constant's enum type.

valueOf

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

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

Parameters:

enumType - the class of the enumerated type to search for the constant value.

name - the name of the constant value to find.

Returns:

the enum constant.

Throws:

NullPointerException - if either enumType or name are null.

IllegalArgumentException - if enumType is not an enumerated type or does not have a constant value called name.

getSharedConstants

public static <T extends Enum<T>> T[] getSharedConstants(Class<T> enumType)

Returns a shared, mutable array containing the constants of this enum. It is an error to modify the returned array.

finalize

protected final void finalize()

Enum types may not have finalizers.

Overrides:

finalize in class Object

Since:

1.6