Java enum this name

Java enum this name

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 . Note that when using an enumeration type as the type of a set or as the type of the keys in a map, specialized and efficient set and map implementations are available.

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Constructor Detail

Enum

Sole constructor. Programmers cannot invoke this constructor. It is for use by code emitted by the compiler in response to enum type declarations.

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.

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 .

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.

equals

hashCode

public final int hashCode()

clone

protected final Object clone() throws CloneNotSupportedException

Throws CloneNotSupportedException. This guarantees that enums are never cloned, which is necessary to preserve their «singleton» status.

compareTo

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.

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.)

valueOf

public static Enum> T valueOf(Class 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.) Note that for a particular enum type T , the implicitly declared public static T valueOf(String) method on that enum may be used instead of this method to map from a name to the corresponding enum constant. All the constants of an enum type can be obtained by calling the implicit public static T[] values() method of that type.

finalize

protected final void finalize()

Источник

Java enum this name

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 . Note that when using an enumeration type as the type of a set or as the type of the keys in a map, specialized and efficient set and map implementations are available.

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Constructor Detail

Enum

Sole constructor. Programmers cannot invoke this constructor. It is for use by code emitted by the compiler in response to enum type declarations.

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.

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 .

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.

equals

hashCode

public final int hashCode()

clone

protected final Object clone() throws CloneNotSupportedException

Throws CloneNotSupportedException. This guarantees that enums are never cloned, which is necessary to preserve their «singleton» status.

compareTo

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.

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.)

valueOf

public static Enum> T valueOf(Class 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.) Note that for a particular enum type T , the implicitly declared public static T valueOf(String) method on that enum may be used instead of this method to map from a name to the corresponding enum constant. All the constants of an enum type can be obtained by calling the implicit public static T[] values() method of that type.

finalize

protected final void finalize()

Источник

Java enum this name

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 . Note that when using an enumeration type as the type of a set or as the type of the keys in a map, specialized and efficient set and map implementations are available.

Constructor Summary

Method Summary

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

Methods declared in class java.lang.Object

Constructor Detail

Enum

Sole constructor. Programmers cannot invoke this constructor. It is for use by code emitted by the compiler in response to enum type declarations.

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.

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 .

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.

equals

hashCode

public final int hashCode()

clone

protected final Object clone() throws CloneNotSupportedException

Throws CloneNotSupportedException. This guarantees that enums are never cloned, which is necessary to preserve their «singleton» status.

compareTo

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.

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.)

valueOf

public static Enum> T valueOf​(Class 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.) Note that for a particular enum type T , the implicitly declared public static T valueOf(String) method on that enum may be used instead of this method to map from a name to the corresponding enum constant. All the constants of an enum type can be obtained by calling the implicit public static T[] values() method of that type.

finalize

protected final void finalize()

Report a bug or suggest an enhancement
For further API reference and developer documentation see the Java SE Documentation, which contains more detailed, developer-targeted descriptions with conceptual overviews, definitions of terms, workarounds, and working code examples.
Java is a trademark or registered trademark of Oracle and/or its affiliates in the US and other countries.
Copyright © 1993, 2023, Oracle and/or its affiliates, 500 Oracle Parkway, Redwood Shores, CA 94065 USA.
All rights reserved. Use is subject to license terms and the documentation redistribution policy.

Источник

How to use the name() method in Java enums [closed]

It’s difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.

I am going through some code uses the name method of a Java Enum. Can anyone please explain to me how and where to use the name() method of Enum in java.

You use it just like any other method wherever you need the name of the Enum value. What is your doubt?

Enum.name() returns a String that contains the exact name that this Enum ‘instance’ has. Its useful for key-value storage, for example the database ‘Neo4j’ uses it extensively to refer to properties.

2 Answers 2

enum Direction < NORTH("north"), SOUTH("south"), EAST("east"), WEST("west"); private final String printableValue; Direction(String printableValue) < this.printableValue = printableValue; >@Override public String toString() < return printableValue; >> 

Direction travelDirection = Direction.NORTH; System.out.println("I am going " + travelDirection); 

Direction travelDirection = Direction.NORTH; System.out.println("I am going " + travelDirection.name()); 

The name() method is pretty much like toString() except that it is declared final, so the enum definition cannot change it. This might be important e.g. when writing a framework to serialize data, where you have to rely on the fact that the name of an enum is a single Java identifier which uniquely identifies the constant. There might be some more applications, but as the manual says:

Most programmers should use the toString() method in preference to this one, as the toString method may return a more user-friendly name.

In general I’d say you should use toString() when the output is intended for a human reader, and name() when it is aimed at another process for parsing in some way.

Источник