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Clément Crepy
Clément Crepy

Reputation: 51

Java Generic Csv String to Enum List

I would like to genericly convert String in csv form to List of enum. However java won't recognise the generic enum type.

I'm using Guava and can't use Java 8.

Any idea ?

public static <E extends Enum<E>> List<E> getEnumList(String csvLine) {
    List<String> csvList = Arrays.asList(csvLine.split(","));

    Function<String, E> enumList = new Function<String, E>() {
       @Override
       public E apply(String csvStr) {
          return Enum.valueOf(E.class, csvStr);
       }
    };

    return Lists.transform(csvList, enumList);
}

Upvotes: 2

Views: 1330

Answers (1)

Konstantin Yovkov
Konstantin Yovkov

Reputation: 62864

You have to pass the Class<E>, because E will be erased (and replaced with something specific at Runtime).

Something like:

public static <E extends Enum<E>> List<E> getEnumList(String csvLine, Class<E> clazz) {
    List<String> csvList = Arrays.asList(csvLine.split(","));

    Function<String, E> enumList = new Function<String, E>() {
       @Override
       public E apply(String csvStr) {
          return Enum.valueOf(clazz, "");
       }
    };

    return Lists.transform(csvList, enumList);
}

As a side note, I guess you have to replace the empty string "" with csvStr, otherwise the csvStr parameter doesn't make any sense.

Upvotes: 3

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