Implementing Validation in Patient, Order, and Cart Modules

Business Scenario

The objective of this lab is to implement input validation for Patient, Order, and CartItem modules using Spring Boot validation annotations. This ensures that only valid and meaningful data is processed by the backend system.

Frontend applications allow users to:

Add items to cart
Enter patient details
Place orders

Introduction (Frontend Perspective)

Without validation:

Invalid cart quantities may be stored
Incorrect patient data may be saved
Orders may contain incomplete or incorrect details

Validation ensures:

Clean and accurate data
Improved user experience
Prevention of runtime errors

Add Validation Dependency

Ensure the following dependency is present in pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

Dependency added

Apply Validation in Entities

Patient Entity

@NotBlank → for name
@Min → for age
@NotBlank → for address

Order Entity

@Positive → for totalAmount
@NotBlank → for status
@NotBlank → for paymentStatus
@NotNull → for createdAt

CartItem Entity

@Min → for quantity
@NotNull → for user
@NotNull → for medicine

Enable Validation in Controller

Add @Valid annotation in POST methods:

Example:

@PostMapping
public CartItem add(@Valid @RequestBody CartItem item) {
    return service.addToCart(item);
}

Apply same for:

PatientController
OrderController

Controller validation

Validation Flow

Request comes from frontend/Postman
Controller receives request
Validation is applied
If valid → Service executes
If invalid → Error response returned

Test APIs using Postman

1. Patient Validation

Valid JSON

{
  "name": "Ramesh",
  "age": 30,
  "address": "Mumbai"
}

Invalid JSON

{
  "name": "",
  "age": 0,
  "address": ""
}

2. Order Validation

Valid JSON

{
  "totalAmount": 500,
  "status": "PLACED",
  "paymentStatus": "PAID",
  "createdAt": "2026-06-10T10:00:00"
}

Invalid JSON

{
  "totalAmount": -100,
  "status": "",
  "paymentStatus": "",
  "createdAt": null
}

3. CartItem Validation

Valid JSON

{
  "quantity": 2,
  "user": { "id": 1 },
  "medicine": { "id": 1 }
}

Invalid JSON

{
  "quantity": 0,
  "user": null,
  "medicine": null
}

Postman validation responses

Global Exception Handling

Use @RestControllerAdvice to handle validation errors:

Returns clean error messages
Improves API response structure
Error response

Run Application

Start Spring Boot application
Verify validation is working
Application running

Verify Results

Valid data → saved successfully
Invalid data → rejected with error messages
Database contains only correct data
Database records

Pre-Lab Preparation

Explore different restaurants
View food items and menus
Add items to cart
Place orders online

Topic : Weaving the world of Web

1) Navigating the world of Web

2) Building Blocks of Website,

3) Tag Titans: Fundamental Web Construct.

git pull origin branchName

Git Pull

Task 1: Understanding BRD

Before you start building anything, you need to clearly understand what the client actually wants.So, let’s begin by understanding the BRD (Business Requirement Document) shared by the client.

BRD Full Form is Business Requirement Details.BRD like a plan for building a house. This plan helps the builder understand what to build.In the same way,BRD tells developers what the client wants to build

Click to download BRD : BiteBox_BRD.pdf

Activity

After going through BRD list down the Core Features and Web Pages in the tabulated Format as shown Below.

Col 1	Col 2	Col 3
Row 1
Row 2
Row 3

Formula

Profit = Revenue - Cost

Task 2: Create WireFrame

Now that you understand the requirements, don’t jump into coding yet. Before development, we always visualize the layout.

Now lets create a simple wireframe for the homepage.

A wireframe is like a layout plan of a house. Before building, you decide where rooms, doors, and windows will be placed.Similarly, a wireframe helps you plan where elements like headers, images, and buttons will appear on a webpage—before adding design or colours.

Task 3: Code Editor Installation

Good work on completing the planning phase.

Now we will start development. Before that, make sure your system is ready with the required tools.

In this step we will install the VS code editor that will help to Write code efficiently,Organize files , Run and test your application

Go to the visual studio code official website

Click to download Homepage Wireframe : Homepage Wireframe

Link - https://code.visualstudio.com/download

Choose your operating system(windows / Mac) and download the installation file.

Double click on the download app and Accept the agreement and click next

It is a long established fact that a reader will be distracted

Sub Steps

Double click on the download app and Accept the agreement and click next

public class MathSample {
    public static void main(String[] args) {
        int x = 10;
        int y = 20;
        int sum = x + y;
        
        System.out.println("The sum is: " + sum);
    }
}

public class MathSample {
    public static void main(String[] args) {
        int x = 10;
        int y = 20;
        int sum = x + y;
        
        System.out.println("The sum is: " + sum);
    }
}

public class MathSample {
    public static void main(String[] args) {
        int x = 10;
        int y = 20;
        int sum = x + y;
        
        System.out.println("The sum is: " + sum);
    }
}

Great job!
You have successfully completed your first lab on BiteBox Project Onboarding.

In this lab, you have: Understood the BRD, Created a wireframe, Set up your development environment, Organised your project structure, Run your first program

You are now ready to move to the next stage of development

Checkpoint

Next-Lab Preparation

Git Push

git push origin branchName

Topic : Working with a Text and Listin HTML

1) Power of HTML text tags
2) Customizing your style with CSS
3) Listing it right using HTML
4) HTML Link up , attributes of tag, block vs inline elements

Text box Width : 887
Business Scenario, Pre-lab Preparation, Next-lab Preparation, Task, Activity, Checkpoint : 90%.
Steps : 1,2,3 [Sub Steps - a,b,c]
Normal Text, Topic Name : 80%
Subtopic : 70%
Code Box font Size : 16px

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