Java中的枚举enum

public class EnumTest {

    enum RadioState {

        RADIO_OFF,         /* Radio explictly powered off (eg CFUN=0) */

        RADIO_UNAVAILABLE, /* Radio unavailable (eg, resetting or not booted) */

        SIM_NOT_READY,     /* Radio is on, but the SIM interface is not ready */

        SIM_LOCKED_OR_ABSENT,  /* SIM PIN locked, PUK required, network

                               personalization, or SIM absent */

        SIM_READY,         /* Radio is on and SIM interface is available */

        RUIM_NOT_READY,    /* Radio is on, but the RUIM interface is not ready */

        RUIM_READY,        /* Radio is on and the RUIM interface is available */

        RUIM_LOCKED_OR_ABSENT, /* RUIM PIN locked, PUK required, network

                                  personalization locked, or RUIM absent */

        NV_NOT_READY,      /* Radio is on, but the NV interface is not available */

        NV_READY;          /* Radio is on and the NV interface is available */



        public boolean isOn() /* and available...*/ {

            return this == SIM_NOT_READY

                    || this == SIM_LOCKED_OR_ABSENT

                    || this == SIM_READY

                    || this == RUIM_NOT_READY

                    || this == RUIM_READY

                    || this == RUIM_LOCKED_OR_ABSENT

                    || this == NV_NOT_READY

                    || this == NV_READY;

        }



        public boolean isAvailable() {

            return this != RADIO_UNAVAILABLE;

        }



        public boolean isSIMReady() {

            return this == SIM_READY;

        }



        public boolean isRUIMReady() {

            return this == RUIM_READY;

        }



        public boolean isNVReady() {

            return this == NV_READY;

        }



        public boolean isGsm() {

            return this == SIM_NOT_READY

                    || this == SIM_LOCKED_OR_ABSENT

                    || this == SIM_READY;

        }



        public boolean isCdma() {

            return this ==  RUIM_NOT_READY

                    || this == RUIM_READY

                    || this == RUIM_LOCKED_OR_ABSENT

                    || this == NV_NOT_READY

                    || this == NV_READY;

        }

    }



	public static void main(String[] args) {

		RadioState mRS = RadioState.RADIO_OFF;



		System.out.println("RadioState isOn: " + mRS.isOn());

		System.out.println("RadioState.RADIO_OFF: " + mRS.RADIO_OFF);

	}

}

1. RadioState枚举类就是class，而且是一个不可以被继承的final类。其枚举值(RADIO_OFF...)都是RadioState类型的静态常量，

2. 即然枚举类是class，当然在枚举类型中有构造器，方法和数据域。但是，枚举类的构造器有很大的不同： 

  (1) 构造器只是在构造枚举值的时候被调用。  

  (2) 构造器只能私有private，绝对不允许有public构造器。

3. 所有枚举类都继承了Enum的方法.

 

参考文章：http://www.javaeye.com/topic/477731