How to convert multiple values to enum in RequestParm?

Question

I have this enum declaration below

public enum FamilyType {
    FIRSTNAME("firstname"),
    LASTNAME("lastname");

    private final String type;

    FamilyType(String type) {
        this.type = type;
    }

    public static FamilyType fromString(String type) {
        for (FamilyType t : FamilyType.values()) {
            if (t.type.equals(type)) {
                return t;
            }
        }
        return converter(type);
    }

    @Deprecated
    private static FamilyType converter(String value) {
        if ("NICKNAME".equalsIgnoreCase(value)) {
            return FIRSTNAME;
        }
        if ("SURENAME".equalsIgnoreCase(value)) {
            return LASTNAME;
        }

        throw new InvalidFileNameException("my-enum", value);
    }
}

and I have a controller endpoint where the delete request holds the FamilyType as Requestparam like the following

public String deleteFamilyType(@PathVariable String userId, @Valid @RequestParam FamilyType familyType) {

while sending from postman familytype=firstname, it works but if sending familytype=nickname then my converter returns

org.springframework.web.method.annotation.MethodArgumentTypeMismatchException:
Failed to convert value of type 'java.lang.String' to required type 'FamilyType';
nested exception is java.lang.IllegalArgumentException: 
No enum constant FamilyType.NICKNAME
at org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:133)
at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)
at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:167)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.

Answer 1

Following this tutorial section 3, we can use custom converter to override the default conversion Enum#valueOf.

public class StringToFamilyTypeConverter implements Converter<String, FamilyType> {
    @Override
    public FamilyType convert(String source) {
        if ("NICKNAME".equalsIgnoreCase(source)) {
            return FamilyType.FIRSTNAME;
        }
        if ("SURENAME".equalsIgnoreCase(source)) {
            return FamilyType.LASTNAME;
        }
        return FamilyType.valueOf(source.toUpperCase());
    }
}

And then add the converter to MVC configuration

@Configuration
public class AppConfig implements WebMvcConfigurer {
    // ...
    @Override
    public void addFormatters(FormatterRegistry registry) {
        registry.addConverter(new StringToFamilyTypeConverter());
    }
    // ...
}