Parking Lot System: Code

#webdev #beginners #designsystem #tutorial

🔥 We'll start from building a Spring Boot Application. Because of some inbuilt annotations. For example: If you want to use Getter setters in the following class:-



package src.entities;

import src.enums.VehicleType;

public class Ticket {
    int floorNo;
    int price;
    String name;
    long time;
    VehicleType vehicleType;
    ParkingSpot parkingSpot;
}

Then you have to write code for a constructor and getters and setters of floorNo, price, name etc.

Yes, you don't need to learn Spring Boot, Just go through this blog to know about its basic things.

Note:- As in our previous blog of Parking Lot System Design, we discussed about its various components and design in this series of LLD (Low level design)

😎 Today We'll go through the code of Parking lot system

📍 We will implement few of the components like ParkingSpot, Vehicle, VehicleType, ParkingStraegy, Ticket etc.

You can refer this code and further can build Entrance, CostComputation etc

🎉 Let's go through the code

📍 Our Entities are:-

ParkingSpot ```JAVA

package com.parkinglotsystem.main.entities;

import com.parkinglotsystem.main.parking.ParkingType;

public interface ParkingSpot {
public boolean isEmpty();
public void occupy();
public void vacateParkingSpot();
public ParkingType getType();

}

- Ticket
```JAVA


package com.parkinglotsystem.main.entities;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
@AllArgsConstructor
public class Ticket {
    int floorNo;
    int price;
    String name;
    long time;
    Vehicle vehicle;
    ParkingSpot parkingSpot;
}

Vehicle ```JAVA

package com.parkinglotsystem.main.entities;

import com.parkinglotsystem.main.enums.VehicleType;

public class Vehicle {
VehicleType vehicleType;
String color;
String vehicleNumber;
}


### 📍 Our enum is:-
- VehicleType
```JAVA


package com.parkinglotsystem.main.enums;

public enum VehicleType {
    TWO_WHEELER("two_wheeler"),
    THREE_WHEELER("three_wheeler"),
    FOUR_WHEELER("four_wheeler");

    private final String value;

    private VehicleType(String value) {
        this.value = value;
    }

    public String getValue() {
        return value;
    }
}

📍 Our Parking Components are:-

ParkingSpotStrategy ```JAVA

package com.parkinglotsystem.main.parking;

import com.parkinglotsystem.main.entities.ParkingSpot;

import java.util.List;
import java.util.Optional;

public interface ParkingSpotStrategy {
Optional findParkingSpot(List parkings);
}

- DefaultParkingSpotStrategy
```JAVA


package com.parkinglotsystem.main.parking;

import com.parkinglotsystem.main.entities.ParkingSpot;

import java.util.List;
import java.util.Optional;

public class DefaultParkingStrategy implements  ParkingSpotStrategy{

    @Override
    public Optional<ParkingSpot> findParkingSpot(List<ParkingSpot> parkings){
        return parkings.stream()
                .filter(parkingSpot -> parkingSpot.getType().equals(ParkingType.TWO_WHEELER) && parkingSpot.isEmpty())
                .findFirst();
    }
}

ParkingSpotManager ```JAVA

package com.parkinglotsystem.main.parking;

import com.parkinglotsystem.main.entities.ParkingSpot;
import com.parkinglotsystem.main.entities.Ticket;
import com.parkinglotsystem.main.entities.Vehicle;
import lombok.AllArgsConstructor;

import java.util.List;
import java.util.Optional;

@AllArgsConstructor
public class ParkingSpotManager {
private List parkings;
public Optional findParkingSpot(ParkingSpotStrategy ps){
return ps.findParkingSpot(parkings);
}

public boolean parkVehicle(Vehicle v, Ticket t, ParkingSpotStrategy ps){
    Optional<ParkingSpot> parkingSpot = findParkingSpot(ps);
    if(parkingSpot.isPresent()){
        parkingSpot.get().occupy();
        return true;
    }
    return false;
}

}


- ParkingType
```JAVA


package com.parkinglotsystem.main.parking;

public enum ParkingType {
    TWO_WHEELER("twoWheeler"),
    THREE_WHEELER("threeWheeler"),
    FOUR_WHEELER("fourWheeler");

    private final String value;

    ParkingType(String value) {
        this.value = value;
    }

    public String getValue() {
        return value;
    }
}

TwoWheelerParkingSpot ```JAVA

package com.parkinglotsystem.main.parking;

import com.parkinglotsystem.main.entities.ParkingSpot;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.Setter;

@Getter
@setter
@AllArgsConstructor
public class TwoWheelerParkingSpot implements ParkingSpot {
private boolean isOccupied;
private int noOfFloor;
private int price;

@Override
public boolean isEmpty(){
    return !isOccupied;
}

@Override
public void occupy(){
    this.isOccupied = true;
}

@Override
public void vacateParkingSpot(){
   this.isOccupied = false;
}

@Override
public ParkingType getType(){
    return ParkingType.TWO_WHEELER;
}

}


> Note that we used different annotations like 
```TEXT


@Getter @Setter @AllArgCsConstructor

These annotations are provided by lombok that is included in build.gradle file so that it can be imported.

🚀 That was it for today, You will get an understanding of how to code from LLD and How easy it is. Further you can complete this code and make a PR to contribute to this project.

Thanks and Follow for more