Java Exercises

This repository contains two separate Java projects:

• exercise-1:
• Project 1 description
• Design Patterns Demo (Standalone)

This is a standalone Java console project that demonstrates six software design patterns in a smart-office context:

• Behavioral: Chain of Responsibility (booking validation), State (energy modes)
• Creational: Builder (BookingRequest), Abstract Factory (controller families)
• Structural: Decorator (retry + audit notifications), Adapter (legacy turnstile → Sensor)

Plain Java (no Maven/Gradle). Tested on JDK 25 (works on JDK 17+).

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Project layout

patterns/ └─ src/ └─ main/ └─ java/ └─ com/smartoffice/patterns/ ├─ demo/PatternsDemoApp.java # main() ├─ behavioral/chain/... # Chain of Responsibility ├─ behavioral/state/... # State ├─ creational/builder/... # Builder ├─ creational/abstractfactory/... # Abstract Factory ├─ structural/decorator/... # Decorator ├─ structural/adapter/... # Adapter └─ shared/... # lightweight domain helpers

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Build & Run (Windows PowerShell / VS Code)

cd patterns

compile all sources to .\out

javac -encoding UTF-8 -d out $((Get-ChildItem -Recurse -Path src\main\java -Filter *.java).FullName)

run the demo (main class)

java -cp out com.smartoffice.patterns.demo.PatternsDemoApp

what the demo prints

chain of responsibility, state, builder, abstract factory, decorator, adapter

• exercise-2: Project 2 description

• Exercise 2 — Smart Office Facility (Console App)

A console application to manage a smart office: room configuration, booking/cancel, sensor-based occupancy (≥2 people), 5-minute no-show auto-release, AC/Lights automation with temperature scaling, authentication & roles, usage stats, and notifications — with solid OOP, clean error handling, and pattern-driven design.

Plain Java (no Maven/Gradle). Tested on JDK 25 (works on JDK 17+).

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Project layout

smart-office-pro/ └─ src/ └─ main/ └─ java/ └─ com/smartoffice/ ├─ App.java # main() ├─ core/, commands/, services/... ├─ observer/, rules/, sensors/, notify/ ... └─ (optionally) patterns/ # if you included the 6 pattern demos here too

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Build & Run (Windows PowerShell / VS Code)

cd smart-office-pro

compile to .\out

javac -encoding UTF-8 -d out $((Get-ChildItem -Recurse -Path src\main\java -Filter *.java).FullName)

run main

java -cp out com.smartoffice.App

Default login: admin admin123

sample input

login admin admin123 config room count 3 create_user alice USER password1 logout login alice password1 block room 1 23:00 60 add occupant 1 2 room status 1 rooms unoccupied

features checklist

Configuration: set number of rooms; per-room max capacity

Booking: create & cancel bookings (conflict checks, ownership/admin rules)

Occupancy rule: room becomes OCCUPIED when ≥ 2 people are inside (add occupant or sensor enter/exit)

No-show auto-release: booking is released if not occupied within 5 min of start time

Automation:

Lights & AC ON when occupied; OFF when unoccupied

AC temperature scales with headcount (cooler as room fills)

Auth & roles: Admin/User; change password; set contact info

Usage: summary and per-room usage stats; list unoccupied rooms

Notifications: console “Email/SMS” lines on auto-release

negative/edge cases

already booked (overlap)

block room 1 23:00 60

cancel not booked

cancel room 2

insufficient occupancy info

add occupant 2 1

non-existent room

add occupant 4 2

invalid room number token

block room A 09:00 60

invalid capacity format

config room max capacity 1-5

commands reference(help)

Auth: login logout whoami change_password set_contact <email|- > <phone|- >

Admin: create_user <ADMIN|USER> list_users config room count config room max capacity

User: block room HH:mm block room HH:mm cancel room add occupant sensor enter sensor exit room status rooms unoccupied

Usage: usage summary usage room

Other: help exit