PackageDeliveriesTracker
fileName: String, packageList: ArrayList<PackageInfo>, rtaf: RuntimeTypeAdapterFactory, gson: GsonBuilder
save():void, load(): void, main(String[] args): void

PackageInfo
name: String, notes: String, price: double, weight, double, deliver: boolean, expectedDate: LocalDateTime
compareTo(PackageInfo p): int, toString(): String
	BookPackage
	authorName: String
	
	PerishablePackage
	expiryDate:LocalDateTime
	
	ElectronicPackage
	handlingFee: double
	

TextMenu
title: String, options: String[]
display(): void, list(ArrayList<PackageInfo> packageList): void, add(ArrayList<PackageInfo> packageList): void, remove(ArrayList<PackageInfo> packageList): void, sortList(ArrayList<PackageInfo> packageList, boolean due): ArrayList<PackageInfo>, overDueList(ArrayList<PackageInfo> packageList): void, getUndelivered(List<PackageInfo> packageList): ArrayList<PackageInfo>
upcomingList(ArrayList<PackageInfo> PackageList): void, markDelivered(ArrayList<PackageInfo> PackageList): void

PackageFactory
PackageType: enum
getInstance(packageType type, String name, String Notes, double price, double weight, boolean delivered, LocalDateTime expectedDate, string author, LocalDateTime expiryDate, double handlingFee): PackageInfo


1. PackageInfo and subclass are created from PackageFactory
2. PackageDeliveriesTracker creates objects of PackageInfo
3. PackageDeliveriesTracker is dependent on TextMenu