How to generate data class from class instance - kotlin

Question

I've got some configuration values in a JSON file which I want to parse via gson to a data-class. I want to generate a new class, based on the created data-class where the values are final.
This all should happen during my CI-Pipeline and the generated class should then be used when my application is running.
Simple example to clarify:
I've got this data class
data class MyDataClass(val name:String, val age:Int)
and via parsing (gson) a instance like this is created
MyDataClass("john", 42)
Is there a way to create a (data) class based on the new instance of MyDataClass so anything like this will be created?
class MyDataClassFinal{
val name = "john"
val age = 42
}

Answer 1

Use .copy() and modify only the parameters you need to. For example:
val joe = MyDataClass(“Joe”, 42)
val mary = joe.copy(name = “Mary”) // age is 42

Answer 2

I've got some configuration values in a json file wich I want to parse via gson to a data-class. I want to generate a new class, based on the created data-class where the values are final.
There is nothing for you to do here. The data class, as you've described it, is final. It is not open so the class is final and the fields are vals and only set via constructor, so they can't be changed, so they too are final.
You can see the Java equivalent of the class by going to doing a search for "Actions", looking for Kotlin Bytecode, then hit Decompile to see the Java source. It looks like this:
#Metadata(
mv = {1, 1, 18},
bv = {1, 0, 3},
k = 1,
d1 = {"\u0000 \n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0000\n\u0002\u0010\u000e\n\u0000\n\u0002\u0010\b\n\u0002\b\t\n\u0002\u0010\u000b\n\u0002\b\u0004\b\u0086\b\u0018\u00002\u00020\u0001B\u0015\u0012\u0006\u0010\u0002\u001a\u00020\u0003\u0012\u0006\u0010\u0004\u001a\u00020\u0005¢\u0006\u0002\u0010\u0006J\t\u0010\u000b\u001a\u00020\u0003HÆ\u0003J\t\u0010\f\u001a\u00020\u0005HÆ\u0003J\u001d\u0010\r\u001a\u00020\u00002\b\b\u0002\u0010\u0002\u001a\u00020\u00032\b\b\u0002\u0010\u0004\u001a\u00020\u0005HÆ\u0001J\u0013\u0010\u000e\u001a\u00020\u000f2\b\u0010\u0010\u001a\u0004\u0018\u00010\u0001HÖ\u0003J\t\u0010\u0011\u001a\u00020\u0005HÖ\u0001J\t\u0010\u0012\u001a\u00020\u0003HÖ\u0001R\u0011\u0010\u0004\u001a\u00020\u0005¢\u0006\b\n\u0000\u001a\u0004\b\u0007\u0010\bR\u0011\u0010\u0002\u001a\u00020\u0003¢\u0006\b\n\u0000\u001a\u0004\b\t\u0010\n¨\u0006\u0013"},
d2 = {"Lcore/lib/extensions/MyDataClass;", "", "name", "", "age", "", "(Ljava/lang/String;I)V", "getAge", "()I", "getName", "()Ljava/lang/String;", "component1", "component2", "copy", "equals", "", "other", "hashCode", "toString", "treking-android.dominicore-android"}
)
public final class MyDataClass {
#NotNull
private final String name;
private final int age;
#NotNull
public final String getName() {
return this.name;
}
public final int getAge() {
return this.age;
}
public MyDataClass(#NotNull String name, int age) {
Intrinsics.checkParameterIsNotNull(name, "name");
super();
this.name = name;
this.age = age;
}
#NotNull
public final String component1() {
return this.name;
}
public final int component2() {
return this.age;
}
#NotNull
public final MyDataClass copy(#NotNull String name, int age) {
Intrinsics.checkParameterIsNotNull(name, "name");
return new MyDataClass(name, age);
}
// $FF: synthetic method
public static MyDataClass copy$default(MyDataClass var0, String var1, int var2, int var3, Object var4) {
if ((var3 & 1) != 0) {
var1 = var0.name;
}
if ((var3 & 2) != 0) {
var2 = var0.age;
}
return var0.copy(var1, var2);
}
#NotNull
public String toString() {
return "MyDataClass(name=" + this.name + ", age=" + this.age + ")";
}
public int hashCode() {
String var10000 = this.name;
return (var10000 != null ? var10000.hashCode() : 0) * 31 + this.age;
}
public boolean equals(#Nullable Object var1) {
if (this != var1) {
if (var1 instanceof MyDataClass) {
MyDataClass var2 = (MyDataClass)var1;
if (Intrinsics.areEqual(this.name, var2.name) && this.age == var2.age) {
return true;
}
}
return false;
} else {
return true;
}
}
}
As you can see, the class, it's fields, and their accessors are all final.