Enum in Java

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. The radiostate enumeration class is a class which cannot be inherited. The enumerated values (radio_off...) are static constants of the radiostate type,

2. The enumeration class is a class. Of course, there are constructors, methods, and data fields in the enumeration type. However, the constructors of enumeration classes are very different:

(1) The constructor is called only when constructing enumeration values.

(2) The constructor can only be private. It is absolutely not allowed to have a public constructor.

3. All enumeration classes inherit the enum method.

 

Reference: http://www.javaeye.com/topic/477731