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kotlinlang

```
fun bindView(
    position: Int,
    view: ListItemView // Interface
  ) = when (ViewTypeEnum.values()[position]) {
    ENUM1 -&gt; bindViewType1(view as ViewType1)
    ENUM2 -&gt; bindViewType2(view as ViewType2)
  }
```

<@U1RF0TMMJ> What does the whole class look like?

Get rid of this enum and the `values()` call. It allocates a new array (defensive copy) each time you call it

Do you have an alternative for ensuring type safety? I’m willing to allocate a new array to ensure type safety because the performance hit is negligible.

we need more information to really give you a good solution. post the whole class for exampel

<@U1RF0TMMJ> Actually, in this case, the performance hit may not be that negligible on a low end phone where you scroll very fast, because it is in a recyclerview that can bind a lot of items per seconds.

<@U1RF0TMMJ> My recyclerview view types are not type safe, but it doesn't matter, I check by hand I handle it properly. It's all in one class, with only 2-3 usages after all.

<@U3ZLHBTLG> Thanks for the insight, you definitely don’t want to be doing allocations every time you’re binding a view. I’ve modified my code to avoid instantiating a new array every time.

```
fun bindView(
  position: Int,
  view: ListItemView
) = when (ViewTypeEnum.values[position]) {
  ENUM1 -&gt; bindViewType1(view as ViewType1)
  ENUM2 -&gt; bindViewType2(view as ViewType2)
}

class ViewTypeEnum {
  ENUM1, ENUM2
  
  companion object {
    val values: Array&lt;ViewTypeEnum&gt; = ViewTypeEnum.values()
  }
}
```

<@U1RF0TMMJ> I guess you meant `enum class` with a `;` after the last enum value `ENUM2`, but yes, such code is better. :thumbsup: You could also add `@JvmField` to `values` :wink:

<@U3ZLHBTLG> The code I posted was a scrubbed down version to remove domain specific details. The real code compiles, I promise haha. This project is 100% kotlin so I don’t do interop code :slightly_smiling_face: Thanks again for the help!

<@U1RF0TMMJ> `@JvmField` is for performance, not for interop. You can make your enum class private BTW.

<@U3ZLHBTLG> How does `@JvmField` improve performance?

<@U1RF0TMMJ> Saves a method call (getter), which still has a bit more overhead over a field access on dalvik VM or ART

btw, your code is not typesafe, it can still fail at runtime without the compiler being able to tell you that you are doing something wrong