Java enumeration examples

Java enumeration examples

We have learned enumeration when learning programming languages. Now let's take a look at the usage of enumeration in java.

The Code is as follows:

Public class test {

Public static void main (String [] args ){

WeekDay w = WeekDay. MON;

System. out. println (w); // you can call the tostring method.

System. out. println (w. ordinal (); // print the objects in the enumeration list.

System. out. println (WeekDay. values (). length); // The total number of enumerated objects.

}

Public enum WeekDay {

SAT, MON, TUE, WED, THU, FRI, SAT,

Private WeekDay (){

System. out. println ("11 ");

}

Private WeekDay (int ){

System. out. println ("");

}

}

}

 

 

First, we define a simple enumeration class WeekDay.

 

Sat, mon... and so on in this class are actually weekday class objects.

 

Note:

 

Enumeration classes also have constructor methods, which must be private;

 

The following code can be used to understand the usage of enumeration types. It should be understood in combination with internal classes.

 

The Code is as follows:

Public enum TrefficLamp {

RED (30) {// The construction method for calling the parameter of the RED light object to be int type,

Public TrefficLamp nextLamp (){

Return GREEN;

}

},

GREEN (20 ){

Public TrefficLamp nextLamp (){

Return YELLOW;

}

},

YELLOW (2 ){

Public TrefficLamp nextLamp (){

Return RED;

}

};

Public abstract TrefficLamp nextLamp ();

Private int time;

Private TrefficLamp (int time ){

This. time = time;

};

}