Common method of enumeration

Turn: https://www.cnblogs.com/liaojie970/p/6474733.html

Use a: constant

public enum Color {  
  RED, GREEN, BLANK, YELLOW  
}

Usage of Two: switch

enum Signal {
        GREEN, YELLOW, RED
    }

    public class TrafficLight {
        Signal color = Signal.RED;

        public void change() {
            switch (color) {
            case RED:
                color = Signal.GREEN;
                break;
            case YELLOW:
                color = Signal.RED;
                break;
            case GREEN:
                color = Signal.YELLOW;
                break;
            }
        }
    }

　　

Use three: add a new method to enumeration

public enum Color {
    RED ( "red", 1), GREEN ( "green", 2), BLANK ( "White", 3), YELLO ( "yellow", 4);
    // Member variables
    private String name;
    private int index;

    // Construction method
    private Color(String name, int index) {
        this.name = name;
        this.index = index;
    }

    // common method
    public static String getName(int index) {
        for (Color c : Color.values()) {
        if (c.getIndex() == index) {
            return c.name;
        }
        }
        return null;
    }

    // get set method
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getIndex() {
        return index;
    }

    public void setIndex(int index) {
        this.index = index;
    }
    }

　　

Usage four: covering enumeration method

public class Test {
    public enum Color {
        RED ( "red", 1), GREEN ( "green", 2), BLANK ( "White", 3), YELLO ( "yellow", 4);
        // Member variables
        private String name;
        private int index;

        // Construction method
        private Color(String name, int index) {
            this.name = name;
            this.index = index;
        }

        // override method
        @Override
        public String toString() {
            return this.index + "_" + this.name;
        }
    }

    public static void main(String[] args) {
        System.out.println(Color.RED.toString());
    }
}