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This article is about how java defines the values and descriptions of Enum class implementations. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

Define Enum class implementation values and descriptions

In computer programming languages such as C++ and Java, enumerated types (Enum) are special data types that can define a set of predefined constants for a variable. When using an enumerated type, the enumerated type variable must be one of its predefined values.

1. Enumerated types implemented with the class keyword

Before JDK5, the Java language did not support enumerated types, and only classes (class) were used to simulate the implementation of enumerated types.

/ * * order status enumeration * / public final class OrderStatus {/ * attribute related * / / * * status value * / private final int value; / * * status description * / private final String description; / * * constant dependent * / * * created (1) * / public static final OrderStatus CREATED = new OrderStatus (1, "created") / * * in progress (2) * / public static final OrderStatus PROCESSING = new OrderStatus (2, "in progress"); / * completed (3) * / public static final OrderStatus FINISHED = new OrderStatus (3, "completed"); / * * constructor * / private OrderStatus (int value, String description) {this.value = value; this.description = description } / * * get the status value * / public int getValue () {return value;} / * * get the status description * / public String getDescription () {return description;}} 2. Enumerated types implemented with the enum keyword

JDK5 provides a new type-- the enumerated type of Java. The keyword enum can create a limited set of named values as a new type, and these named values can be used as constants, which is a very useful function.

/ * * order status enumeration * / public enum OrderStatus {/ * constant dependent * / / * * created (1) * / CREATED (1, "created"), / * * in progress (2) * / PROCESSING (2, "in progress"), / * completed (3) * / FINISHED (3, "completed") / * * attribute related * / / * * status value * / private final int value; / * * State description * / private final String description; / * * Constructor * / private OrderStatus (int value, String description) {this.value = value; this.description = description } / * * get the status value * / public int getValue () {return value;} / * * get the status description * / public String getDescription () {return description;}}

In fact, the Enum type is a syntax sugar, and the compiler helps us parse and compile the syntax. Through decompilation, you can see that the Java enumeration is actually compiled to generate a class that inherits java.lang.Enum and adds common methods for enumerated types such as values () and valueOf ().

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