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

  • Method Summary

    Modifier and Type Method 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 Details

    • 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 Details

    • 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