Model with multi-listeners.

MultiListeners.kt

interface OnModelChangeListener {
    fun onModelChangeName(model: Model, name: String)
}

class Model {
    var name = ""
        set(value) {
            field = value
            publishChangedName(value)
        }

    private var listeners = mutableMapOf<String, OnModelChangeListener>()

    fun addListener(listener: OnModelChangeListener) {
        val key = listener.hashCode().toString()
        listeners[key] = listener
    }

    fun removeListener(listener: OnModelChangeListener) {
        val key = listener.hashCode().toString()
        listeners.remove(key)
    }

    fun publishChangedName(name: String) {
        listeners.forEach { (_, value) ->
            value.onModelChangeName(this, name)
        }
    }
}