basvanmeurs

export default class Account extends StateMachine {

    constructor() {
        this._balance = 0;
    }

    $enter() {
        this.open();
    }

basvanmeurs

import Account from "./Account.js";

export default class StealingAccount extends Account {

    constructor() {
        super();
        this._stolen = 0;
    }

    getRealAvailable() {

basvanmeurs

package org.mypackage.util

import java.lang.ref.Reference
import java.lang.ref.ReferenceQueue
import java.lang.ref.WeakReference

/**
 * WeakMap that uses identity comparison rather than equality comparison ([java.util.WeakHashMap]).
 * Useful for instance mappings.
 *

basvanmeurs

class TargetClass {} // External class to be extended

class Extra(var name: String = "")
val state = mutableMapOf<TargetClass, Extra>()
fun TargetClass.getState(): Extra {
 return state.getOrPut(this) { Extra() }
}

fun TargetClass.setName(v: String) {
 getState().name = v;