JVD CLI — Java Days 2025

A modern, extensible Java CLI showcasing algorithms, utilities, and a rich terminal printing toolkit (colors, progress bars, tables, spinners). Built with Java 21 and Gradle. Perfect for demos, interviews, and as a base for premium CLI tooling.

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Table of Contents

• Features
• Quick Start
• Run It
• Usage
• Command Reference
• PrintHelpers (UI/UX Toolkit)
• Configuration
• Architecture
• Extending with New Commands
• Packaging & Distribution
• Tech Stack
• Why It Stands Out
• Screenshots
• Releases
• Roadmap
• Pro / Premium Edition
• Contributing
• License
• Changelog

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Features

• Fast, friendly CLI with discoverable help topics
• Math utilities: sum, average, min, max
• Array utilities: sort, reverse, unique
• Generators: random arrays, maps, matrices
• Rich terminal printing helpers:
  • Colors, titles, sections, separators
  • Multi-line boxes, spinners, progress bars, ASCII tables
  • Fluent logging builder with levels (INFO, WARN, SUCCESS, ERROR, DEBUG, TRACE)
  • Configurable colors and timestamp format
• Clean, testable command registry pattern (easy to add new commands)

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Quick Start

Requirements:

• Java 21+
• Git

Clone and build (Windows cmd):

git clone https://github.com/senanqulamov/JavaDays.git
cd JavaDays
.\gradlew.bat build

Run from Gradle (Windows cmd):

.\gradlew.bat run

Run the packaged JAR:

java -jar build\libs\JavaDays-1.0.0.jar

Note: ANSI colors are supported on most modern terminals. On older Windows shells, enable "Virtual Terminal Processing" or use Windows Terminal/PowerShell.

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Run It

When you start the app you’ll see a short progress bar, a title, and a welcome box. At the prompt, type commands and press Enter.

Example session:

jvd> help
jvd> generate array 5
jvd> sum 1 2 3 4 5
jvd> array sort 5 2 8 1 9
jvd> generate matrix 3 4
jvd> exit

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Usage

Core global commands:

• help or h — Show help and topics
• version or v — Show application version
• exit or quit — Quit the CLI

Help topics:

• help sum
• help generate
• help array
• help map

Generators:

• generate sum [count] — Generate random array and print sum
• generate array [count] — Generate a random array
• generate map [size] — Generate random key/value pairs
• generate matrix [rows] [cols] — Generate a 2D matrix

Math:

• sum <numbers...>
• avg <numbers...>
• max <numbers...>
• min <numbers...>

Array ops:

• array sort <numbers...>
• array reverse <numbers...>
• array unique <numbers...>

Defaults and limits:

• Default generated size: 10
• Max array/map size: 100,000
• Random values range: 0–99

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Command Reference

Quick reference for all built-ins (abbreviations included):

Command	Description
help, h	Show general help
help sum	Help for sum operations
help generate	Help for generate commands
help array	Help for array operations
help map	Help for map generation
version, v	Show version
exit, quit	Exit application
generate sum [count]	Generate array and print sum
generate array [count]	Generate and display array
generate map [size]	Generate random map
generate matrix [rows] [cols]	Generate a 2D matrix
sum <n...>	Sum numbers
avg <n...>	Average of numbers
max <n...>	Maximum value
min <n...>	Minimum value
array sort <n...>	Sort ascending
array reverse <n...>	Reverse input
array unique <n...>	Unique elements

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PrintHelpers (UI/UX Toolkit)

The jvd.Helpers.PrintHelpers module powers formatted output. Highlights:

• Fluent logging API:

  import static jvd.Helpers.PrintHelpers.*;
  
  log().level(LogLevel.WARNING).message("Low disk space").print();
  log().level(LogLevel.INFO).format("User %s logged in", username).print();
  log().level(LogLevel.SUCCESS).message("Done").sameLine().print();

• Colors, titles, sections, separators:

  printTitle("JVD CLI");
  printSection("Math utilities");
  printSeparator();

• Boxes, progress, spinners, tables:

  printBox(
      "Welcome to the optimized PrintHelpers!",
      "",
      "Key improvements:",
      "• Fluent Builder API",
      "• Progress bars and tables",
      "• Better performance with StringBuilder",
      "• Configurable colors and timestamps"
  );
  
  for (int i = 0; i <= 100; i++) { printProgressBar(i, 100); Thread.sleep(15); }
  printSpinner("Executing", 1000);
  
  String[] headers = {"Name", "Age", "Role"};
  String[][] rows = {{"John","28","Dev"},{"Sarah","32","Manager"}};
  printTable(headers, rows);

• Debug and formatting helpers:

  printDebug(() -> expensiveDebugMessage());
  printFormattedInfo("Items: %d", items.size());

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Configuration

You can tweak behavior at runtime:

// Toggle debug logs
setDebugMode(true);   // or disableDebug(); enableDebug();

// Customize timestamp format
setTimestampFormat(java.time.format.DateTimeFormatter.ofPattern("HH:mm:ss"));

// Customize log level colors
setLevelColor(LogLevel.WARNING, jvd.Helpers.Colors.AnsiColor.CYAN);

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Architecture

• jvd.Main — entry point. Initializes UI, starts REPL loop.
• Functions.Commands — command registry and handlers. Declarative registerCommand mapping to handler methods; robust arg parsing helpers.
• jvd.Helpers.PrintHelpers — rich terminal output utilities (colors, boxes, progress, tables, spinner, builder-style logging).
• jvd.Helpers.Colors — ANSI color definitions.

Why this approach:

• Simple to extend: add a handler and one registration line.
• Testable: pure handlers operating on a context with parsed args.
• UX-first: consistent, colorful output aids demos and interviews.

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Extending with New Commands

Add a command in Functions/Commands.java:

// 1) Register it (in the static initializer)
registerCommand("greet", Commands::handleGreet, "Say hello");

// 2) Implement the handler
private static void handleGreet(CommandContext ctx) {
    printSuccess("Hello from JVD!");
}

The context helpers make parsing easy:

int count = ctx.getIntArg(0, 10);  // first arg or default
int[] numbers = ctx.getIntArrayArgs(); // parse all as ints

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Packaging & Distribution

Standard Gradle build creates:

• Executable JAR: build/libs/JavaDays-1.0.0.jar
• Distributions (zip/tar) with launch scripts: build/distributions/JavaDays-1.0.0.zip
  • Windows launcher inside the unzipped folder: bin/JavaDays.bat

Build:

.\gradlew.bat clean build

Run distribution (after unzip the archive into a folder):

.\bin\JavaDays.bat

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Tech Stack

• Language: Java 21
• Build: Gradle (Application plugin)
• Runtime: Console/Terminal (ANSI colors)
• Dependencies: Standard JDK (no external runtime deps)

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Why It Stands Out

• Clear architecture: separation of concerns between UI helpers and command logic
• Extensibility: new commands added with one registration and one handler
• Developer experience: rich formatted output for readable demos
• Performance-minded: StringBuilder usage, lazy debug evaluation, minimal allocations
• Production-ready patterns: configuration knobs, color theming, consistent logging format

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Screenshots

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Releases

Cutting a release publishes build artifacts (JAR + zipped distributions) automatically via GitHub Actions.

Steps:

• Update version in build.gradle if needed
• Commit your changes
• Tag with a semantic version and push the tag:

git tag v1.0.0
git push origin v1.0.0

The workflow .github/workflows/release.yml will build and attach:

• build/libs/*.jar
• build/distributions/*.zip and .tar

Find releases here: https://github.com/senanqulamov/JavaDays/releases

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Roadmap

• Command history and better input editing
• Config file (YAML/JSON) for defaults and theming
• File/JSON logging modes and log rotation
• Unit tests for command handlers and helpers
• More algorithms (searching, sorting variants, stats)
• Plugin system for user-defined commands

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Pro / Premium Edition

A premium version will include:

• Extended logging (file, JSON, structured events)
• Rich themes, light/dark palettes, and branding
• Scripting mode and batch command files
• Performance metrics, benchmarks, and profiling helpers
• Auto-complete, suggestions, and fuzzy matching
• Signed installers and enterprise packaging

Interested in a commercial license or custom features? Reach out to me to discuss a Pro build tailored to your needs.

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Contributing

Issues and PRs are welcome. If you’d like ideas, check the Roadmap. Keep code clean, cohesive and documented. Small, focused PRs are preferred.

See the full guide: CONTRIBUTING.md

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License

MIT © 2025 Senan Qulamov — See LICENSE for details.

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Changelog

Track notable changes in CHANGELOG.md. The release workflow is tag-driven (see Releases).