Simple enum question

how can i reverse lookup the string value if given the int value for the given enum? so if i am given an int value of 0 it should return a value of "Freshman 1"I cant figure it out.

public enum YearsInSchool {
FRESHMAN1(0, "Freshman 1"), 
FRESHMAN2(1, "Freshman 2"), 
SOPHOMORE1(2, "Sophomore 1"), 
SOPHOMORE2(3, "Sophomore 2"), 
JUNIOR1(4, "Junior 1"), 
JUNIOR2(5, "Junior 2"), 
SENIOR1(6, "Senior 1"), 
SENIOR2(7, "Senior 2"), 
GRADUATE(8, "Graduate"), 
FACULTY(9, "Faculty");

private int intVal;
private String strVal;开发者_运维知识库

YearsInSchool(int intValIn, String strValIn){
    intVal = intValIn;
    strVal = strValIn;      
}

public int getIntVal() {
    return intVal;
}

public String getStrVal() {
    return strVal;
}

}

---

YearsInSchool.values()[0]; will get you the first enum value.

Also enum has a built in ordinal() method that returns it's index in the set. It seems like you are just replicating this with your intVal.

---

If you don't want to make it dependent on order of constants, you can use a lookup table initialized in static block:

public enum YearsInSchool {
    ...
    private static Map<Integer, YearsInSchool> intsToValues = new HashMap<Integer, YearsInSchool>();
    static {
        for (YearsInSchool y: values())
            intsToValues.put(y.getIntValue(), y);
    }

    public static YearsInSchool getByInt(int y) {
        return intsToStrings.get(y);
    }
}

---

This should return FRESHMAN1.

YearsInSchool yis = (YearsInSchool) YearsInSchool.class.getEnumConstants()[0];

if you what "Freshman 1", you should be able to do yis.getStrVal()

---

If you use Bala's answer you are locked in to keeping everything in sequence. I prefer to create a lookup map.

private static Map<Integer, YearsInSchool> intMap 
  = new HashMap<Integer, YearsInSchool>();

in your ctor add the line intMap.put(intVal, this);

add the method

public static YearsInSchool getByInt(int n) {
  return intMap.get(n); // error handling omitted here
}

Now you can add more enum values for situations you did not consider; you don't need them all in order. (For example, you could have enums for REDSHIRT_FRESHMAN etc.)

---

Just use the code below and you can call the method getStrValIn on enum class

public enum YearsInSchool {
    FRESHMAN1(0, "Freshman 1"), FRESHMAN2(1, "Freshman 2"), SOPHOMORE1(2,
            "Sophomore 1"), SOPHOMORE2(3, "Sophomore 2"), JUNIOR1(4, "Junior 1"), JUNIOR2(
            5, "Junior 2"), SENIOR1(6, "Senior 1"), SENIOR2(7, "Senior 2"), GRADUATE(
            8, "Graduate"), FACULTY(9, "Faculty");

    private int intVal;
    private String strVal;

    YearsInSchool(int intValIn, String strValIn) {
        intVal = intValIn;
        strVal = strValIn;
    }

    public static String getStrValIn(int intValIn){

        YearsInSchool[] values = values();

        for (YearsInSchool yearsInSchool : values) {

            if(yearsInSchool.getIntVal() == intValIn){return yearsInSchool.getStrVal();}
        }

        return null;
    }

    public int getIntVal() {
        return intVal;
    }

    public String getStrVal() {
        return strVal;
    }

}

This will solve your problem