cmpt213-a2/src/Main.java

import com.google.gson.*;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import java.io.*;
import java.time.LocalDateTime;
import java.time.chrono.ChronoLocalDate;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
private static final String fileName = "list.json";
    private static ArrayList<PackageInfo> packageList=new ArrayList<>();
private static void save(){
    Gson gson = new GsonBuilder().registerTypeAdapter(LocalDateTime.class,
            new TypeAdapter<LocalDateTime>() {
                @Override
                public void write(JsonWriter jsonWriter,
                                  LocalDateTime localDateTime) throws IOException {
                    jsonWriter.value(localDateTime.toString());
                }
                @Override
                public LocalDateTime read(JsonReader jsonReader) throws IOException {
                    return LocalDateTime.parse(jsonReader.nextString());
                }
            }).create();
    try{
        Writer w = new FileWriter(fileName);
        gson.toJson(packageList, w);
        w.flush();
        w.close();
    }
    catch (IOException e){
        e.printStackTrace();
    }
}

private static void load(){
    File file = new File(fileName);
try{
    JsonElement element = JsonParser.parseReader(new FileReader(fileName));
    JsonArray array = element.getAsJsonArray();
    for (int i = 0; i < array.size(); i++){
        JsonObject pObj = array.get(i).getAsJsonObject();
        DateTimeFormatter format = DateTimeFormatter.ofPattern("yyy-MM-dd HH:mm");
        packageList.add(new PackageInfo(pObj.get("name").getAsString(),
                pObj.get("note").getAsString(),
                pObj.get("price").getAsDouble(),
                pObj.get("weight").getAsDouble(),
                        pObj.get("delivered").getAsBoolean(),
                LocalDateTime.parse(pObj.get("expectedDate").getAsString()))
        );
    }
    System.out.println("packages loaded");
}
catch (FileNotFoundException e){
System.out.println("no packages to load");
    }
}

    public static void main(String[] args) {
TextMenu menu=new TextMenu();
load();
do{
    menu.display();
    System.out.println("choose an option between 1 and 7:");
    Scanner scan = new Scanner(System.in);
    int option=Integer.parseInt(scan.nextLine());
    if (option > 7 || option < 1){
        System.out.println("invalid input");
    }
    else if(option == 7){
        save();
        System.out.print("packages saved");
        break;
    }
    else{
        switch(option){
            case 1: menu.list(packageList);
                    break;
            case 2: menu.add(packageList);
            break;
            case 3: menu.remove(packageList);
            break;
            case 4: menu.overDueList(packageList);
            break;
            case 5: menu.upcomingList(packageList);
            break;
            case 6: menu.markDelivered(packageList);
        }
    }
}
while (true);
    }
}