CODEWITHSUNDEEP
javaenumscommand-line-arguments
user3896551
user3896551

Reputation: 17

Can you use a switch statement with a list of enums in java 6?

I know you can have something like 

public enum letters{
                    A, B, C, D
                   }

then have something like with each letter having its own class with a method

switch(letters)
case A:
      A.methodA();
      break;
case B:
        B.methodB();
      break;
case C:
        C.methodC();
      break;
case D:
       D.methodD();
      break;
default:
      System.out.println("Learn the alphabet");

but can you have something like

switch(listOfLetterEnums)
 ...

In my program I turn command line enum arguments into a list and I need to know how to run each of the enums' method from that list whether it be a switch statement or something else.

I should add when I try it I get an error saying "cannot convert List. Only convertible int values or enum variables" would converting to a list of enums work if the above is possib

Upvotes: 0

Views: 1414

Answers (3)

PandaConda
PandaConda

Reputation: 3516

You will need to put a for loop around the switch statement to parse each element of the list separately. If the list is an Iterable then it should look something like this:

for (letterEnum : listOfLetterEnums) {
    switch(letterEnum) {
        ...
    }
}

For this to work, your list will need to implement the Iterator interface or extend a class which implements it. In this case you probably want to extend ArrayList.

If the list is an array you can just parse each element of the array:

for (int i = 0; i < listOfLetterEnums.length; i++) {
    switch(listOfLetterEnums[i]) {
        ...
    }
}

Upvotes: 2

Sizik
Sizik

Reputation: 1066

You need to loop over the list, and switch based on the value.

letters[] listOfLetterEnums = { letters.A, letters.B, letters.C, letters.D };
for(letter let : listOfLetterEnums)
{
    switch(let)
    {
    case A:
        A.methodA();
        break;
    case B:
        B.methodB();
        break;
    case C:
        C.methodC();
        break;
    case D:
        D.methodD();
        break;
    default:
        System.out.println("Learn the alphabet");
    }
}

Upvotes: 0

Andreas
Andreas

Reputation: 5103

public class Test {
    private enum Foo {
        ABC, DEF;
    }

    public static void main(String... args) {
        List<Foo> myfoos = new ArrayList<Foo>();
        myfoos.add(Foo.ABC);
        for(Foo i:myfoos)
        switch (i) {
        case ABC:
            System.out.println("do abc");
            break;
        case DEF:
            System.out.println("do def");
            break;
        }
    }
}

Upvotes: 0

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