📚 Library Management System

A full-stack multitenant library management application built with SAP Cloud Application Programming Model (CAP) for Java, designed for deployment on SAP Business Technology Platform (BTP).

🎯 Overview

This application provides comprehensive library management capabilities with support for books, members, and loan tracking. It includes automatic fine calculation, email validation, duplicate prevention, and is designed for SaaS multitenancy deployment.

✨ Features

Core Functionality

📖 Book Management: Create, read, update, and delete books with automatic stock tracking
👥 Member Management: Register and manage library members with email validation
📋 Loan Management: Track book loans with automatic due date calculation (30 days)
💰 Fine Calculation: Automatic fine calculation for overdue returns (₹10/day)
🔄 Return Processing: Book return with fine calculation and stock updates

Business Logic

✅ Automatic stock validation (prevents over-lending)
✅ Duplicate book prevention (updates stock instead of creating duplicates)
✅ Email validation for members
✅ Email verification for book returns (security feature)
✅ Prevents member deletion if they have active loans
✅ Automatic stock increment/decrement on loan/return

Technical Features

🔐 OAuth2 authentication via XSUAA
🏢 Multitenancy ready with SaaS Registry integration
🌐 RESTful OData V4 API
📊 SAP HANA Cloud database support
🚀 Cloud Foundry deployment ready
🔄 Blue-green deployment support

🏗️ Architecture

Technology Stack

Layer	Technology
Backend Framework	SAP CAP Java (Spring Boot 3.5.8)
Database	SAP HANA Cloud / H2 (local)
Build Tool	Maven 3.x
Runtime	Java 17
API Protocol	OData V4
Authentication	XSUAA (OAuth2)
Routing	Application Router
Deployment	Cloud Foundry (SAP BTP)

🚀 Getting Started

Prerequisites

Before you begin, ensure you have the following installed:

Java 17 or higher (Download)
Maven 3.6+ (Download)
Node.js 18+ and npm (Download)
SAP Cloud Foundry CLI (for deployment) - Install Guide
Cloud MTA Build Tool (for building) - npm install -g mbt

📥 Installation

Clone the repository

git clone <your-repository-url>
cd library-management

Install root dependencies
```
npm install
```

Install service dependencies and build

cd srv
mvn clean install -DskipTests
cd ..

After clean install, go to srv/src/gen and mark the java folder as "Generated Sources Root" in your IDE.

💻 Running Locally

Run with Maven (Recommended for Development)

Navigate to service directory
```
cd srv
```
Run the application
```
mvn spring-boot:run
```
Access the application
- 🌐 Application: http://localhost:8080
- 📊 OData Service: http://localhost:8080/odata/v4/LibraryService
- 📖 Service Metadata: http://localhost:8080/odata/v4/LibraryService/$metadata

🔨 Building for Production

Build MTA Archive

The Multi-Target Application (MTA) archive bundles all components for deployment:

# Build the MTA archive
mbt build

# Output: mta_archives/library-management_1.0.0.mtar

This command:

✅ Builds the Java service (srv)
✅ Packages the database module (db)
✅ Packages the application router (approuter)
✅ Creates a deployable .mtar file

Build Components Separately (Optional)

Build Java Service:

cd srv
mvn clean package -DskipTests

Build Database Module:

cd db
npm install

☁️ Deployment to SAP BTP

Prerequisites for Deployment

SAP BTP Account (Trial or Production)
Cloud Foundry Space with appropriate entitlements
Required Services:
- SAP HANA Cloud (or hdi-shared for trial)
- XSUAA
- SaaS Registry (for multitenancy)

Step-by-Step Deployment

1. Login to Cloud Foundry

cf login -a <api-endpoint>

2. Target Your Org and Space

cf target -o <your-org> -s <your-space>

3. Deploy the MTA Archive

cf deploy mta_archives/library-management_1.0.0.mtar

Deployment process includes:

✅ Creating/updating services (library-db, library-uaa, library-registry)
✅ Deploying database schema (library-management-db-deployer)
✅ Deploying Java service (library-management-srv)
✅ Deploying application router (library-management-approuter)

Expected deployment time: 8-12 minutes

4. Verify Deployment

# Check applications
cf apps

# Check services
cf services

# View application logs
cf logs library-management-srv --recent

Accessing Your Deployed Application

After successful deployment:

Application URLs:

Service: https://<org>-<space>-library-management-srv.cfapps.<region>.hana.ondemand.com
Approuter: https://<org>-<space>-library-management-approuter.cfapps.<region>.hana.ondemand.com

📡 API Documentation

OData V4 Endpoints

Base URL: https://<your-app-url>/odata/v4/LibraryService

Books

Method	Endpoint	Description
GET	`/Books`	List all books
POST	`/Books`	Create a new book
GET	`/Books({ID})`	Get book by ID
PATCH	`/Books({ID})`	Update book
DELETE	`/Books({ID})`	Delete book

Example Book Entity:

{
  "title": "Clean Code",
  "author": "Robert C. Martin",
  "stock": 5
}

Members

Method	Endpoint	Description
GET	`/Members`	List all members
POST	`/Members`	Register a member
GET	`/Members({ID})`	Get member by ID
PATCH	`/Members({ID})`	Update member
DELETE	`/Members({ID})`	Delete member

Example Member Entity:

{
  "name": "John Doe",
  "email": "john.doe@example.com"
}

Loans

Method	Endpoint	Description
GET	`/Loans`	List all loans
POST	`/Loans`	Create a loan
GET	`/Loans({ID})`	Get loan by ID

Example Loan Entity:

{
  "bookId": "book-uuid",
  "memberId": "member-uuid",
  "loanDate": "2026-01-11",
  "dueDate": "2026-02-10",
  "returnDate": null
}

Return Book:

POST /odata/v4/LibraryService/returnBook
Content-Type: application/json

{
  "loanId": "loan-uuid",
  "email": "john.doe@example.com"
}

Response: { "value": 50 }  // Fine amount

Subscription API (Multitenancy)

Method	Endpoint	Description
GET	`/mt/v1.0/subscriptions/dependencies`	Get subscription dependencies
PUT	`/mt/v1.0/subscriptions/tenants/{tenantId}`	Subscribe a tenant
DELETE	`/mt/v1.0/subscriptions/tenants/{tenantId}`	Unsubscribe a tenant

🔐 Security & Authentication

Local Development

Mock authentication enabled by default
No login required for testing

Production (BTP)

OAuth2 authentication via XSUAA
Role-based access control
Two main roles:
- Admin: Full access to all operations
- MTCallback: Subscription management

Configuring Users (Production)

Go to BTP Cockpit
Navigate to your subaccount → Security → Role Collections
Assign users to role collections

🧪 Sample Usage Scenarios

Scenario 1: Adding Books and Members

# Add a book
curl -X POST http://localhost:8080/odata/v4/LibraryService/Books \
  -H "Content-Type: application/json" \
  -d '{
    "title": "The Pragmatic Programmer",
    "author": "David Thomas",
    "stock": 3
  }'

# Register a member
curl -X POST http://localhost:8080/odata/v4/LibraryService/Members \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Jane Smith",
    "email": "jane.smith@example.com"
  }'

Scenario 2: Creating a Loan

curl -X POST http://localhost:8080/odata/v4/LibraryService/Loans \
  -H "Content-Type: application/json" \
  -d '{
    "bookId": "<book-id>",
    "memberId": "<member-id>",
    "loanDate": "2026-01-11",
    "dueDate": "2026-02-10"
  }'

Scenario 3: Returning a Book (On Time)

curl -X POST http://localhost:8080/odata/v4/LibraryService/returnBook \
  -H "Content-Type: application/json" \
  -d '{
    "loanId": "<loan-id>",
    "email": "jane.smith@example.com"
  }'

# Response: { "fine": 0 }  // No fine

Scenario 4: Returning a Book (Overdue)

If the book is returned 5 days late:

# Response: { "fine": 50 }  // ₹10 × 5 days = ₹50

🔧 Configuration

application.yaml

Key configurations:

cds:
  multitenancy:
    enabled: true          # Enable multitenancy
    tenantId: request      # Extract tenant from request
  
  security:
    authentication-strategy: never  # Disable auth for subscription endpoints

xs-security.json

Defines OAuth2 security:

Scopes: Admin, Callback, mtcallback
Role templates
Grant authorities for SaaS Registry

mta.yaml

Multi-Target Application descriptor:

Defines modules (db, srv, approuter)
Configures services (HANA, XSUAA, SaaS Registry)
Sets up routes and dependencies

⚠️ Known Limitations

Trial Account Limitations

What Works:

✅ All CRUD operations
✅ Business logic (loans, returns, fines)
✅ Subscription API endpoints (return HTTP 200)
✅ Single-tenant deployment

What Doesn't Work:

❌ Multitenancy with tenant-specific HDI containers
❌ Tenant database isolation
❌ Full SaaS subscription flow

Why: Trial accounts don't have access to HANA Cloud's HDI container provisioning for tenants.

Solution: For production multitenancy, deploy to a production BTP account with HANA Cloud service.

🐛 Troubleshooting

Build Issues

Maven build fails:

# Clean and rebuild
cd srv
mvn clean install -U

MTA build fails:

# Clean build artifacts
rm -rf mta_archives/ node_modules/ srv/target/
npm install
mbt build

Deployment Issues

Service creation fails:

# Check service status
cf services

# View service creation logs
cf service library-db

Application won't start:

# View application logs
cf logs library-management-srv --recent

# Check application details
cf app library-management-srv

Runtime Issues

Database connection errors:

Verify HANA service is running
Check service binding: cf env library-management-srv

Authentication errors:

Verify XSUAA service configuration
Check xs-security.json is correctly deployed

🧹 Maintenance

Update Dependencies

# Update Node.js dependencies
npm update

# Update Maven dependencies
cd srv
mvn versions:display-dependency-updates

Clean Build Artifacts

# Remove all build artifacts
rm -rf mta_archives/ node_modules/ srv/target/ db/gen/

# Reinstall and rebuild
npm install
mbt build

Redeploy

# Rebuild and redeploy
mbt build
cf deploy mta_archives/library-management_1.0.0.mtar

📊 Database Schema

Entity Relationships

Members (1) ──< (N) Loans (N) >── (1) Books

Key Fields

Books:

ID (UUID, Primary Key)
title (String)
author (String)
stock (Integer)
Managed fields (createdAt, createdBy, modifiedAt, modifiedBy)

Members:

ID (UUID, Primary Key)
name (String)
email (String, unique)
Managed fields

Loans:

ID (UUID, Primary Key)
bookId (UUID, Foreign Key)
memberId (UUID, Foreign Key)
loanDate (Date)
dueDate (Date, auto-calculated as loanDate + 30 days)
returnDate (Date, nullable)
fine (Integer, default 0)
Managed fields

🙏 Acknowledgments

Version: 1.0.0
Last Updated: January 11, 2026
Status: ✅ Production Ready (Single-tenant) | ⚠️ Multitenancy requires HANA Cloud

Name		Name	Last commit message	Last commit date
Latest commit History 2 Commits
approuter		approuter
db		db
srv		srv
.cdsrc.json		.cdsrc.json
.gitignore		.gitignore
README.md		README.md
mta.yaml		mta.yaml
package-lock.json		package-lock.json
package.json		package.json
pom.xml		pom.xml
xs-security.json		xs-security.json

hritamkar/library-management

Folders and files

Latest commit

History

Repository files navigation