My name
is
Jon Skeet

how to convert "value" to enum?

I have this enum class:

public enum IconImageTag {

    None("val1"),
    USD("val2"),
    EURO("val3");
}

given a string which represent a "value" (say `"val"1)

how can I convert it to the corresponding enum?

update

I have tried this. Why is this illegal to access static member from the ctor? I get an error.

  private final String value;
    private static final Map<String, IconImageTag> stringToEnumMap = new HashMap<>();

    IconImageTag(String value) {
        this.value = value;
        stringToEnumMap.put(value, this);
    }

Ideally, you'd build up a Map<String, IconImageTag> and add an appropriate method. For example:

public enum IconImageTag {
    NONE("val1"),
    USD("val2"),
    EURO("val3");

    private final String value;

    private final Map<String, IconImageTag> valueMap = new HashMap<>();

    static {
        for (IconImageTag tag : values()) {
            valueMap.put(tag.value, tag);
        }
    }

    private IconImageTag(String value) {
        this.value = value;
    }

    public static IconImageTag fromValue(String value) {
        return valueMap.get(value);
    }
}

(I'd probably use a different term from "value" here, to avoid confusion with valueOf() etc...)

Note the use of the static initializer block - any static variables in an enum are initialized after the enum values themselves, which means that when the enum constructor runs, valueMap will still be null.

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