CODEWITHSUNDEEP
kotlin
Jasper Blues
Jasper Blues

Reputation: 28776

Kotlin : Interface with immutable property implemented by class with mutable

I have the following code:

Instead of inject the mutable TokenConfigurationConfig we inject the interface.

public interface TokenAuthenticationConfig {

    public fun apiKey() : String

}

@Component
@ConfigurationProperties(prefix = "service.api")
public open class TokenAuthenticationConfigImpl : TokenAuthenticationConfig
{
    public var apiKey : String

    constructor() {
        this.apiKey = ""
    }

    override fun apiKey(): String
    {
        return this.apiKey
    }
}

It works ok, but just wondering:

Uses of the interface would see the property as immutable, while users of the class would see it as mutable.

Upvotes: 3

Views: 1218

Answers (1)

voddan
voddan

Reputation: 33819

Yes, it definitely is possible to define such an interface and a class.

Any (publicly visible) property x in Kotlin means a pair of methods getX() and setX(..), generated by the compiler to satisfy the Java convention. That said, it is consistent that you can override getX in a class and add setX.

Here is an example:

interface SomethingImmutable {
    val Somevar: String
}

class MyClass: SomethingImmutable {
    override var Somevar: String = "Initial Value"
}

Upvotes: 3

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