Initial commit

Author: fawazbokhari

.gitignore

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+# Gradle
+.gradle/
+build/
+
+# IDE
+.vscode/
+.idea/
+*.iml
+*.ipr
+*.iws
+/out/
+/oo-design.iml
+
+# Java
+*.class
+*.jar
+*.war
+*.ear
+*.zip
+*.tar.gz
+*.rar
+hs_err_pid*
+replay_pid*
+
+!gradle/wrapper/gradle-wrapper.jar
+!gradle/wrapper/gradle-wrapper.properties
+
+# OS
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+
+# Logs
+*.log
+
+# Temporary files
+*.tmp
+*.temp
+*~
+
+# Maven (if any projects use it)
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+release.properties
+dependency-reduced-pom.xml
+buildNumber.properties
+.mvn/timing.properties
+.mvn/wrapper/maven-wrapper.jar
+
+# JUnit
+TEST-*.xml
+
+# Virtual machine crash logs
+hs_err_pid*
+replay_pid*

MIGRATION_GUIDE.md

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+# Migration Guide: Manual Build → Modern Gradle
+
+Complete guide for migrating Object-Oriented Design projects from manual builds to modern Gradle with VS Code integration.
+
+## Key Improvements
+
+✅ **In-place migration** - No separate directories  
+✅ **Preserve original structure** - Keep existing files as reference  
+✅ **Simple directory mapping** - Direct project directory mapping  
+✅ **Clean multi-project setup** - All projects in one workspace  
+
+## Migration Process
+
+### Step 1: Set Up Multi-Project Structure
+
+Create root-level Gradle files:
+
+**settings.gradle**
+```gradle
+rootProject.name = 'oo-design'
+
+include 'vendingmachine'
+include 'atm'
+// ... other projects
+
+// Map to actual directories
+project(':vendingmachine').projectDir = file('Vending_Machine_Code')
+project(':atm').projectDir = file('ATM_Code')
+// ... other mappings
+```
+
+**build.gradle** (root)
+```gradle
+subprojects {
+    apply plugin: 'java'
+    
+    repositories {
+        mavenCentral()
+    }
+    
+    dependencies {
+        testImplementation 'org.junit.jupiter:junit-jupiter:5.11.0'
+        testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
+    }
+    
+    java {
+        toolchain { languageVersion = JavaLanguageVersion.of(17) }
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+    
+    tasks.named('test') { useJUnitPlatform() }
+}
+```
+
+### Step 2: Migrate Individual Project
+
+For each project directory (e.g., `Vending_Machine_Code/`):
+
+1. **Update the original README**:
+   ```bash
+   cd Vending_Machine_Code/vendingmachine
+   # Update existing README.md to include:
+   # - Gradle build instructions
+   # - All valuable original content (features, classes, test coverage)
+   # - Remove references to manual builds (readers have no context)
+   
+   # All source files stay exactly as-is
+   ```
+
+2. **Create project build.gradle with custom source paths**:
+   ```gradle
+   plugins {
+       id 'java'
+   }
+   
+   // Configure source directories to use original paths
+   sourceSets {
+       main {
+           java {
+               srcDir 'vendingmachine'
+               exclude '**/*Test.java'  // Exclude test files from main
+           }
+       }
+       test {
+           java {
+               srcDir 'vendingmachine'
+               include '**/*Test.java'  // Include only test files
+           }
+       }
+   }
+   ```
+
+
+### Step 3: Test Migration
+
+```bash
+# From root directory
+./gradlew :vendingmachine:build
+./gradlew :vendingmachine:test
+```
+
+### Step 4: Verify Multi-Project Setup
+
+```bash
+./gradlew projects  # Should show all projects
+./gradlew buildAll  # Build everything
+```
+
+## Directory Structure After Migration
+
+```
+oo-design/
+├── build.gradle                    # Root build configuration
+├── settings.gradle                 # Multi-project setup
+├── gradlew, gradlew.bat           # Gradle wrapper
+├── gradle/                        # Wrapper files
+├── .vscode/                       # VS Code configuration
+│
+├── Vending_Machine_Code/          # Original directory (migrated)
+│   ├── build.gradle              # Project-specific config (only new file!)
+│   └── vendingmachine/           # Original directory completely unchanged
+│       ├── README.md             # Updated with Gradle instructions
+│       ├── *.java                # All source and test files
+│       └── combined.plantuml     # UML diagrams in original location
+│
+├── ATM_Code/                     # Next project to migrate
+├── Blackjack_Code/              # Next project to migrate
+└── ...
+```
+
+## Benefits of In-Place Migration
+
+### Before
+```bash
+# Each project had separate build process
+cd Vending_Machine_Code/vendingmachine
+mkdir lib
+curl -L <url> -o lib/junit.jar
+javac -cp lib/junit.jar *.java
+java -jar lib/junit-platform.jar --scan-classpath
+```
+
+### After  
+```bash
+# From root directory
+./gradlew :vendingmachine:test
+./gradlew :atm:test
+./gradlew :blackjack:test
+```
+
+## VS Code Integration
+
+Opening the root folder provides:
+- **All projects in one workspace**
+- **Gradle tasks for each project**
+- **Unified debugging and testing**
+- **No context switching between projects**
+
+## Migration Checklist
+
+For each project:
+
+- [ ] Create project `build.gradle` with custom source paths
+- [ ] Update original README with Gradle instructions  
+- [ ] Test: `./gradlew :project:build test`
+- [ ] Update root README with project status
+- [ ] Configure test output visibility (optional but recommended):
+  ```gradle
+  tasks.named('test') {
+      useJUnitPlatform()
+      testLogging {
+          showStandardStreams = true
+      }
+      outputs.upToDateWhen { false }  // Always run tests, never cache
+  }
+  ```
+
+## Key Advantages
+
+1. **Preserves History**: Original files remain intact
+2. **No Confusion**: Single source of truth per project  
+3. **Easy Navigation**: All projects accessible from root
+4. **Professional Structure**: Industry-standard Gradle layout
+5. **IDE Friendly**: Full VS Code integration
+6. **Reader Friendly**: One command to run any project
+
+This approach transforms the repository into a professional, cohesive development environment while preserving the original educational structure.

README.md

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+# Object-Oriented Design Examples
+
+Companion code repository for "Object-Oriented Design Interview" by ByteByteGo.
+
+## Quick Start
+
+```bash
+git clone <repo-url>
+cd oo-design
+
+# Build all projects
+./gradlew buildAll
+
+# Test a specific project
+./gradlew :vendingmachine:test
+./gradlew :blackjack:test
+./gradlew :tictactoe:test
+```
+
+## Available Projects
+
+| Project | Command |
+|---------|---------|
+| ATM System | `./gradlew :atm:test` |
+| Blackjack | `./gradlew :blackjack:test` |
+| Elevator System | `./gradlew :elevator:test` |
+| File Search | `./gradlew :filesearch:test` |
+| Grocery Store | `./gradlew :grocerystore:test` |
+| Movie Ticket | `./gradlew :movieticket:test` |
+| Parking Lot | `./gradlew :parkinglot:test` |
+| Restaurant | `./gradlew :restaurant:test` |
+| Shipping Locker | `./gradlew :shippinglocker:test` |
+| Tic-Tac-Toe | `./gradlew :tictactoe:test` |
+| Vending Machine | `./gradlew :vendingmachine:test` |
+
+## Requirements
+
+- **Java 17+** (Java 21 LTS recommended)
+
+## Project Commands
+
+```bash
+# List all available projects
+./gradlew projects
+
+# Build specific project
+./gradlew :vendingmachine:build
+
+# Test specific project
+./gradlew :vendingmachine:test
+
+# Build everything
+./gradlew buildAll
+
+# Test everything
+./gradlew runAllTests
+```
+
+## Running Tests
+
+Tests are configured to always show output (stdout/stderr) and run every time (no caching). This makes it easier to see test results and debug issues.
+
+```bash
+# Run tests for a specific project
+./gradlew :vendingmachine:test
+
+# If you need to force re-run cached tests in other projects
+./gradlew :projectname:cleanTest :projectname:test
+```