I have a class ```data class Login get NotBlank get Size min kotlinlang #announcements

07/26/2017, 9:45 AM

I have a class

data class Login(@get:NotBlank @get:Size(min=3) @JsonProperty(value = "login", required = true) val login: String, 
                  @get:NotBlank @JsonProperty(value = "password", required = true) val password: String)

annotations are used for validation, validation is executed after constructor but before validation, I need to trim

login

password

, in order to reject values as " r " for

login

, because real value is "r" and size is 1, which is less than 3 how to do this in Kotlin?

07/26/2017, 9:54 AM

you can try:

class Login(login: String, password: String){
    @get:NotBlank @get:Size(min=3) @JsonProperty(value = "login", required = true) val login: String = login.trim()
    @get:NotBlank @JsonProperty(value = "password", required = true) val password: String = password.trim()
}

however with this approach you cannot have

data

The other approach might be private constructor and factory method

data class Login private constructor(@get:NotBlank @get:Size(min=3) @JsonProperty(value = "login", required = true) val login: String,
                 @get:NotBlank @JsonProperty(value = "password", required = true) val password: String){
    companion object Factory{
        operator fun invoke(login: String, password: String) = Login(login.trim(), password.trim())
    }
}

You then use it as if it was constructor invocation, whereas in fact it is invoking operator

invoke

val login = Login("login", "pass")