Question

im using vaadin with scaladin add-on & have a class extend vaadin.scala.CustomComponent

class CostPlanImport extends CustomComponent {
    var root: Panel = _
    // ..
}

now i want override attach method of com.vaadin.ui.Component class in my class & access my class properties (root,..) in that method.

how i have to do?

Thanks.

Answer 1

As you can see from the CustomComponent source

class CustomComponent(override val p: com.vaadin.ui.CustomComponent with
    CustomComponentMixin = new com.vaadin.ui.CustomComponent with 
    CustomComponentMixin
) extends AbstractComponent(p) {
    ... inner code
}

You pass the corresponding vaadin component as a contructor argument p (which usually stands for “peer”)

That is, the scaladin component is a wrapper around your original component.

To override the behavior of the peer component, you have to do it when you pass it to the wrapper constructor.

You have different choices here

---

With anonymous subclass

class CostPlanImport(override val p: com.vaadin.ui.CustomComponent with CustomComponentMixin =
    new com.vaadin.ui.CustomComponent {
        def attach() {
            //your code here
        } with CustomComponentMixin
) extends CustomComponent(p)

---

With a trait

trait AttachBehavior {
    self: com.vaadin.ui.Component =>
      def attach() {
         //your reusable code here
      }
}

class CostPlanImport(override val p: com.vaadin.ui.CustomComponent with CustomComponentMixin =
    new com.vaadin.ui.CustomComponent 
        with CustomComponentMixin
        with AttachBehavior
) extends CustomComponent(p)

---

With a CustomComponent subclass

[not shown, but is a mix of the preceding two examples]

---

Note: the code examples are not tested

---

UPDATE

If you need to pass parameters from your “wrapper component” constructor to the peer’s method, you can

class CostPlanImport(
    name: String,
    cost: Double,
) extends CustomComponent( p = 
    new com.vaadin.ui.CustomComponent {
        def attach() {
            //your code here
            //with "name" & "cost" visible
        } with CustomComponentMixin
)