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I'm using JAVA 1.6 and Jackson 1.9.9 I've got an enum

public enum Event {

    FORGOT_PASSWORD("forgot password");

    private final String value;

    private Event(final String description) {

        this.value = description;

    }

    @JsonValue

    final String value() {

        return this.value;

    }

}

I've added a @JsonValue, this seems to do the job it serializes the object into:

{"event":"forgot password"}

but when I try to deserialize I get a

Caused by: org.codehaus.jackson.map.JsonMappingException: Can not construct instance of com.globalrelay.gas.appsjson.authportal.Event from String value 'forgot password': value not one of declared Enum instance names

What am I missing here?

1 Answer

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The serializer / deserializer solution pointed out by @xbakesx is an excellent one if you wish to simply decouple your enum class from its JSON representation.

Alternatively, if you prefer a self-contained solution, an implementation based on @JsonCreator and @JsonValue annotations would be more comfortable.

 the following is a complete whole solution (Java 6, Jackson 1.9):

public enum DeviceScheduleFormat {

    Weekday,

    EvenOdd,

    Interval;

    private static Map<String, DeviceScheduleFormat> namesMap = new HashMap<String, DeviceScheduleFormat>(3);

    static {

        namesMap.put("weekday", Weekday);

        namesMap.put("even-odd", EvenOdd);

        namesMap.put("interval", Interval);

    }

    @JsonCreator

    public static DeviceScheduleFormat forValue(String value) {

        return namesMap.get(StringUtils.lowerCase(value));

    }

    @JsonValue

    public String toValue() {

        for (Entry<String, DeviceScheduleFormat> entry : namesMap.entrySet()) {

            if (entry.getValue() == this)

                return entry.getKey();

        }

        return null; // or fail

    }

}

...