Java Reference
In-Depth Information
clone() isoverriddentopreventconstantsfrombeingclonedsothatthereis
pared via == .
equals() isoverriddentocompareconstantsviatheirreferences—constants
with the same identities ( == ) must have the same contents ( equals() ), and
different identities imply different contents.
finalize() is overridden to ensure that constants cannot be finalized.
hashCode() is overridden because equals() is overridden.
toString() is overridden to return the constant's name.
Exceptfor toString() ,alloftheoverridingmethodsaredeclared final sothat
they cannot be overridden in a subclass.
Enum also provides its own methods. These methods include the final com-
pareTo() , ( Enum implements Comparable ), getDeclaringClass() ,
name() , and ordinal() methods:
compareTo() compares the current constant with the constant passed as an
argument to see which constant precedes the other constant in the enum, and
array of unsorted constants.
getDeclaringClass() returns the Class object corresponding to the
currentconstant'senum.Forexample,the Class objectfor Coin isreturned
whencalling Coin.PENNY.getDeclaringClass() for enum Coin {
PENNY, ICKEL, DIME, QUARTER } . Also, TempConversion is
returnedwhencalling TempConversion.C2F.getDeclaringClass()
for Listing 3-65 's TempConversion enum. The compareTo() method
uses Class 's getClass() methodand Enum 's getDeclaringClass()
Otherwise, a ClassCastException is thrown. (I will discuss Class in
Chapter 4 . )
name() returns the constant's name. Unless overridden to return something
more descriptive, toString() also returns the constant's name.
ordinal() returnsazero-based ordinal ,anintegerthatidentifiestheposition
of the constant within the enum type. compareTo() compares ordinals.
Enum also provides the public static <T extends Enum<T>> T
valueOf(Class<T> enumType, String name) method for returning the
enum constant from the specified enum with the specified name:
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