Class Enum
java.lang.Enum All Implemented Interfaces:
-
Direct Known Subclasses:
-
abstract public class Enum
This is the common base class of all Java language enumeration types.
Since:
-
1.5
Version:
-
1.15, 01/27/06
Author:
-
Josh Bloch, Neal Gafter
| Constructor Summary |
protected |
Enum(String name, int ordinal) Sole constructor. |
| Method Summary |
|
clone() Throws CloneNotSupportedException. |
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. |
protected void |
finalize() enum classes cannot have finalize methods. |
|
getDeclaringClass() Returns the Class object corresponding to this enum constant's
enum type. |
int |
hashCode() Returns a hash code for this enum constant. |
|
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). |
|
toString() Returns the name of this enum constant, as contained in the
declaration. |
static T |
valueOf(Class<T> enumType, String name) Returns the enum constant of the specified enum type with the
specified name. |
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
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).
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:
-
the ordinal of this enumeration constant
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:
-
Returns:
-
the name of this enum constant
equals
public final boolean equals(Object other) -
Returns true if the specified object is equal to this
enum constant.
Overrides:
-
Parameters:
-
other - the object to be compared for equality with this object.
Returns:
-
true if the specified object is equal to this
enum constant.
hashCode
public final int hashCode()
-
Returns a hash code for this enum constant.
Overrides:
-
Returns:
-
a hash code for this enum constant.
clone
-
Throws CloneNotSupportedException. This guarantees that enums
are never cloned, which is necessary to preserve their "singleton"
status.
Overrides:
-
Returns:
-
(never returns)
Throws:
-
CloneNotSupportedException - if the object's class does not
support the
Cloneable interface. Subclasses
that override the
clone method can also
throw this exception to indicate that an instance cannot
be cloned.
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:
-
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.
getDeclaringClass
public final 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
Object.getClass() method for enum constants with
constant-specific class bodies.)
Returns:
-
the Class object corresponding to this enum constant's
enum type
valueOf
public static 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.)
-
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:
-
IllegalArgumentException - if the specified enum type has
no constant with the specified name, or the specified
class object does not represent an enum type
-
Since:
-
1.5
finalize
protected final void finalize()
-
enum classes cannot have finalize methods.
Overrides:
-
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