Kotlin - option to generate open class instead of data class

[ntf]

Is your feature request related to a problem? Please describe.
When evaluating Kotlin vs Java code generation, I found that the Java one generates ordinally non final POJO class while Kotlin one generates data class which are not inheritable.

It would be great if we can generate model classes with open class instead or interface for even greater flexibility.

Describe the solution you'd like
An option kotlinGenerateModelInterfaces or kotlinGenerateModelOpenClasses that generate open class or interface instead of data class which can not be inherited.

Describe alternatives you've considered
Generate Java classes instead as models are not final classes. But it would be great to use Kotlin classes.

Additional context
Add any other context or screenshots about the feature request here.

[jxnu-liguobin]

Both kotlin and scala can provide open classes, but we haven't encountered any examples so far, so I'm not sure if we need them.

btw, it takes some time to reconstruct the template. The most crude way is to add if dataclass else openclass to the original template.

[jxnu-liguobin]

If we judge by if ... else ... (as follow), adding support to the existing template will lead to the template growing to hundreds of lines (it is difficult to maintain, which is the same as the scala toString method, although it is not urgent to solve at present). Is there a better way? @kobylynskyi

if have no field
class A

else if disable data class
class A

else
data class A

[kobylynskyi]

@jxnu-liguobin thanks for evaluating this. Sorry that I am not familiar with Kotlin, will you be able to share a sample of data class and open class? How different are they? Is it better to create a separate template file maybe?

[jxnu-liguobin]

Similar to Java POJO,but data class cannot be inherited. The constructor must have a parameter list and will generated automatically Some methods such as toString,equals,hashcode when compile time.Because it can't be inherited,this is the current problem. I'm wondering if I need to use a new file to store the template.

[jxnu-liguobin]

@ntf I have did it at pr #547. Please take a look.
There is also a small change for xxxResponse

[kobylynskyi]

Will be released as part of 4.1.4 soon.