Access Java Enum fields in javascript

Question

I'm trying to access the facility String of this enum in java script

public enum FacilityEnum {

    CAR_VALET("carValet"),
    INDOOR("indoorPark"),
    DISABLED_ACCESS("disabledAccess"),
    EV_CHARGE("evCharge"),

    private String facility;

    private FacilityEnum(String facility) {
        this.facility = facility;
    }

    public String getFacility() {
        return facility;
    }

    public void setFacility(String facility) {
        this.facility = facility;
    }



}

This enum is used in a Facility.class

@Entity
public class Facility {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long facilityId;

    @Enumerated(EnumType.STRING)
    private FacilityEnum service;


    @ManyToMany(mappedBy = "facilities")
    @JsonBackReference("parks-facilities-services")
    private Set<Park> parks;
    }


    public FacilityEnum getService() {
        return service;
    }

    public void setService(FacilityEnum service) {
        this.service = service;
    }

which has a ManyToMany relation with Park.class.

The problem comes when i need to use the facility String in javascript

This the javascript interested part, i'm using Spring + Thymleaf

var parcheggi = JSON.parse([[${parks}]]); //my list of Parks
parcheggi.forEach(function (arrayItem) { //it's ok

            var parcheggio = arrayItem;
            var services = parcheggio.facilities; //it's ok, i get Facility objects
            var servicesDiv = '<div>';
            services.forEach(function (service){
                var s = service; //the single Facility

                servicesDiv += '<img src="/images/park_icons/facilities/' + s.service + '.png" />'
            });
            servicesDiv += '</div>';

 //rest of the code...

In this case s.service is the rough Enum (CAR_VALET, INDOOR...) if i try s.service.facility I get undefined.. I need to have carValet, indoor, disabledAccess and so on...

Answer 1

One way to do what you want is to configure object mapper to serialize enums using toString method. You would add the following to the object mapper configuration:

 objectMapper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);

(Note that previous Jackson versions have equivalent to this property but it's different).

Then just add toString to your enum:

@Override
public String toString ()
{
    return facility;
}

Answer 2

You are getting undefined because your Enum can't be deserialized in JSON, you have two options here:

• Either change the Implementation of your Enum, so it contains only the String constants and it will be correctly mapped by Jackson.

Your code would be:

public enum FacilityEnum {
    CAR_VALET,
    INDOOR,
    DISABLED_ACCESS,
    EV_CHARGE;
}

• Or you should override the toString() method in your Enum so it can be deserialized and returned as a String .

Your code would be:

public enum FacilityEnum {

  CAR_VALET("carValet"),
    INDOOR("indoorPark"),
    DISABLED_ACCESS("disabledAccess"),
    EV_CHARGE("evCharge"),

    private String facility;

  private FacilityEnum(String facility) {
    this.facility = facility;
  }

  public String getFacility() {
    return facility;
  }

  public void setFacility(String facility) {
    this.facility = facility;
  }

  @Override
  public String toString() {
    return facility;
  }

}