I have a class which implement `MutableList<T&g...

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[passsy]

I have a class which implement MutableList<T> with a delegate. The class doesn’t have other properties. How can I write a working equals method which includes the delegate. Can I access it somehow?

class WidgetListBuilder : MutableList<Widget> by mutableListOf() {

    inline fun <T : Widget> add(widget: T, init: T.() -> Unit): T {
        widget.apply(init)
        add(widget)
        return widget
    }

    override fun equals(other: Any?): Boolean {
        if (this === other) return true
        if (other !is WidgetListBuilder) return false
        // TODO handle list
        return true
    }

    override fun hashCode(): Int {
        return javaClass.hashCode()
    }
}

[diesieben07]

This should work:

class WidgetListBuilder private constructor(val delegate: MutableList<Widget>) : MutableList<Widget> by delegate {
    constructor() : this(mutableListOf())
}

[passsy]

Thanks!

[passsy]

adding data class makes it even better!

[passsy]

Alternatively I could use a typealias and a extension function for add to reduce the class overhead

[diesieben07]

Probably a better case for the upcoming inline classes