Telecom Data Aggregator

This Java 21 project processes telecom usage logs to generate aggregated reports per mobile number. It handles large volumes of data, applies rate-based cost computations, and produces structured output with robust error handling and modular design.

🔗 GitHub Repository

Clone or fork the repo from: https://github.com/B-Rajpal/Telecom-calculator.git

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📁 Project Structure

Telecom-aggregator/
├── pom.xml
├── .gitignore
├── README.md
├── input/                      # Sample input files
├── output/                     # Processed reports 
├── test_files/                 # Temporary test files and test report
├── src/
│   ├── main/java/
│   │   └── com/telecom/aggregator/
│   │       ├── App.java        # Entry point
│   │       ├── model/UsageRecord.java
│   │       ├── parser/UsageRecordParser.java
│   │       ├── core/DataAggregator.java
│   │       ├── core/FileProcessor.java
│   │       └── core/CostCalculator.java
│   ├── test/java/
        └── com/telecom/aggregator/core/
            └── AggregatorAndFileProcessorTest.java  # Combined JUnit test class

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⚙️ Features

• Parses and aggregates 4G/5G usage data per user
• Distinguishes roaming vs. non-roaming charges
• Configurable cost computation (threshold penalty, roaming premium)
• Skips malformed lines gracefully
• Outputs result to terminal and to output/report.txt
• Test cases with test output saved in test_files/test-report.txt

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🖥️ How to Run

1. Clone and Open in VSCode or Eclipse

git clone https://github.com/B-Rajpal/Telecom-aggregator.git
cd Telecom-aggregator

2. Import as Maven Project (Eclipse)

• File → Import → Existing Maven Projects
• Browse to the cloned folder
• Build project

3. Run the Application

Run App.java as a Java application. It will:

• Create dummy files with usage data
• Parse and aggregate those files
• Output the results to terminal and to output/report.txt

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📥 Sample Input Format

Each line in the input file (e.g., input/usage_file_1.txt) is:

MobileNumber|Tower|4G|5G|Roaming

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📤 Sample Output Format

Mobile Number|4G|5G|4G Roaming|5G Roaming|Cost

Saved to: output/report.txt

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✅ Test Cases Covered

Test Class: AggregatorAndFileProcessorTest

Test Case	Description	Result
Aggregator Initial State	Ensure aggregator is empty before any usage is added.	✅ PASSED
Single 4G Home Usage	Validate that non-roaming 4G usage is recorded correctly.	✅ PASSED
Single 5G Roaming Usage	Check if 5G usage in roaming is recorded properly.	✅ PASSED
Multiple Records Same Number	Test cumulative addition for same user across roaming and home usage.	✅ PASSED
Multiple Mobile Numbers	Ensure distinct mobile numbers are tracked separately.	✅ PASSED
Null Usage Record	Verify null records are safely ignored without error.	✅ PASSED
File Processing with Valid Data	Test complete data processing pipeline from file to aggregation.	✅ PASSED
File with Malformed Lines	Ensure invalid records are skipped without crashing.	✅ PASSED
Non-existent File Handling	Confirm system handles missing files gracefully.	✅ PASSED

📁 Test Files and Output Directory

All temporary test input files and the generated test report (test-report.txt) are saved in the test_files/ directory during test execution.

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🙋‍♂️ Author

Rajpal B GitHub: B-Rajpal

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Let me know if you find bugs or have suggestions! 🙌