Kotlin create object with params syntax

Question

I have an object

class Person {
@JsonProperty("name")
var name: String? = null

@JsonProperty("id")
lateinit var id: String}

There is an only empty constructor and I want to create a person so I wrote:

 val person = Person()
 person.name = "someName"
 person.id = "SomeId"

I'm pretty sure that there is a prettier syntax, something like

val person = Person {name = "someName" , id = "someId"}

but I can't find an example. am I missing something? should I create a secondary constructor to use this syntax or is there another way?

Manushin Igor · Accepted Answer · 2018-07-17 11:55:55Z

3

Please check apply method.

Your code will be like this:

val person = Person().apply {name = "someName", id = "someId"}

Another way - you can change declaration of Person to (e.g. just change brackets, replace var to val and remove lateinit):

class Person (@JsonProperty("name") val name: String? = null,
              @JsonProperty("id") val id: String )

Then you will able to do this:

val person = Person(name = "someName", id = "someId")

answered Jul 17, 2018 at 11:55

Manushin Igor

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Brijesh Joshi · Accepted Answer · 2018-07-17 11:43:32Z

0

You can achieve it with the constructor parameter.

class Person(
        @JsonProperty("name")
        var name: String? = null,
        @JsonProperty("id")
        var id: String
)



val person = Person(name = "someName", id = "someId")

Another way is make your class and desired variables open to be overridden.

open class Person {
    @JsonProperty("name")
    open var name: String? = null
    @JsonProperty("id")
    open var id: String = ""
}

val person =  object : Person() {
        override var name: String? = "SomeName"
        override var id = "SomeId"
}

answered Jul 17, 2018 at 11:43

Brijesh Joshi

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