Extract jDisco library to separate GitHub repository and consume as Maven dependency

Removed the embedded jDisco module and migrated to consuming jDisco 1.2.0
as an external Maven dependency from GitHub Packages, improving modularity
and maintainability.

Changes:
- Remove jdisco/ subdirectory (59 files) - now maintained at github.com/bedaHovorka/jdisco
- Configure Gradle to fetch jDisco from GitHub Packages with mavenLocal() fallback
- Update Docker build to use GitHub authentication for package access
- Add .env.example for GitHub Packages credentials template
- Update CI/CD workflow to use GitHub token for dependency resolution
- Remove jDisco-specific Maven build from Docker multi-stage process
- Update all documentation to reflect external dependency model

GitHub Packages authentication required for builds:
- Set GITHUB_ACTOR and GITHUB_TOKEN environment variables
- Or configure ~/.gradle/gradle.properties with gpr.user and gpr.key
- CI/CD authentication automatic via GITHUB_TOKEN

Build system now uses three-tier fallback:
1. mavenLocal() cache (fastest, for local jDisco development)
2. GitHub Packages (requires authentication)
3. Build fails with clear error message

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: bedaHovorka

.env.example

@@ -0,0 +1,13 @@
+# GitHub Packages Authentication
+# Copy this file to .env and fill in your credentials
+# Required for downloading jDisco dependency from GitHub Packages
+
+# Your GitHub username
+GITHUB_ACTOR=your-github-username
+
+# Your GitHub Personal Access Token with 'read:packages' scope
+# Generate at: https://github.com/settings/tokens
+GITHUB_TOKEN=your-personal-access-token
+
+# Note: GitHub Packages requires authentication even for public packages
+# See: https://docs.github.com/en/packages/working-with-a-github-packages-registry/working-with-the-gradle-registry

.github/workflows/gradle-java21.yml

@@ -10,6 +10,7 @@ on:
 permissions:
   contents: read
   checks: write  # For test reporting (future)
+  packages: read  # For GitHub Packages (jDisco dependency)
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -35,25 +36,12 @@ jobs:
         distribution: 'temurin'
         java-version: ${{ env.JAVA_VERSION }}
 
-    - name: Cache Maven dependencies (for jDisco)
+    - name: Cache jDisco from GitHub Packages
+      id: cache-jdisco
       uses: actions/cache@v4
       with:
-        path: ~/.m2/repository
-        key: ${{ runner.os }}-maven-${{ hashFiles('jdisco/pom.xml') }}
-        restore-keys: |
-          ${{ runner.os }}-maven-
-
-    - name: Build jDisco library (Java 6 compatibility)
-      working-directory: ./jdisco
-      run: mvn clean install -q
-
-    - name: Verify jDisco installation
-      run: |
-        if [ ! -f ~/.m2/repository/dk/ruc/keld/jdisco/1.2.0/jdisco-1.2.0.jar ]; then
-          echo "ERROR: jDisco artifact not found"
-          exit 1
-        fi
-        echo "✓ jDisco 1.2.0 artifact successfully installed"
+        path: ~/.m2/repository/dk/ruc/keld/jdisco
+        key: jdisco-1.2.0
 
     - name: Setup Gradle
       uses: gradle/actions/setup-gradle@v4
@@ -68,6 +56,9 @@ jobs:
       run: chmod +x gradlew
 
     - name: Build and test interlockSim with Gradle
+      env:
+        GITHUB_ACTOR: ${{ github.actor }}
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       run: ./gradlew clean build shadowJar --no-daemon --warning-mode=all --stacktrace -x integrationTest
 
     - name: Upload JAR artifact

.github/workflows/sonarqube.yml

@@ -11,6 +11,7 @@ permissions:
   contents: read
   checks: write
   pull-requests: read  # Required for PR analysis
+  packages: read  # Required for GitHub Packages (jDisco dependency)
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -40,14 +41,6 @@ jobs:
         distribution: 'temurin'
         java-version: ${{ env.JAVA_VERSION }}
 
-    - name: Cache Maven dependencies (for jDisco)
-      uses: actions/cache@v4
-      with:
-        path: ~/.m2/repository
-        key: ${{ runner.os }}-maven-${{ hashFiles('jdisco/pom.xml') }}
-        restore-keys: |
-          ${{ runner.os }}-maven-
-
     - name: Cache SonarQube packages
       uses: actions/cache@v4
       with:
@@ -56,18 +49,6 @@ jobs:
         restore-keys: |
           ${{ runner.os }}-sonar
 
-    - name: Build jDisco library (Java 6 compatibility)
-      working-directory: ./jdisco
-      run: mvn clean install -q
-
-    - name: Verify jDisco installation
-      run: |
-        if [ ! -f ~/.m2/repository/dk/ruc/keld/jdisco/1.2.0/jdisco-1.2.0.jar ]; then
-          echo "ERROR: jDisco artifact not found"
-          exit 1
-        fi
-        echo "✓ jDisco 1.2.0 artifact successfully installed"
-
     - name: Setup Gradle
       uses: gradle/actions/setup-gradle@v4
       with:
@@ -78,6 +59,9 @@ jobs:
       run: chmod +x gradlew
 
     - name: Build and test with coverage
+      env:
+        GITHUB_ACTOR: ${{ github.actor }}
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       run: ./gradlew clean build test jacocoTestReport --no-daemon --warning-mode=all --stacktrace
 
     - name: Upload JaCoCo coverage report

.gitignore

@@ -39,6 +39,9 @@ text/*.ps
 # Docker artifacts
 artifacts/
 
+# Environment variables (contains sensitive credentials)
+.env
+
 # Maven artifacts (jDisco)
 jdisco/target/
 .m2/

CLAUDE.md

@@ -11,17 +11,22 @@ Railway Interlocking Simulator - A BSc thesis project (2006/2007) from Brno Univ
 
 ## Build System
 
-This project uses Gradle with Kotlin DSL for building. Java 21 LTS is the minimum required version. The jDisco library module remains at Java 6 for compatibility and uses Maven.
+This project uses Gradle with Kotlin DSL for building. Java 21 LTS is the minimum required version.
 
 **Migration Notes**:
 - Migrated from Apache Ant + Ivy to Gradle in January 2026
 - Migrated from Java 11 to Java 21 LTS in January 2026
 - Refactored deprecated Observable/Observer to PropertyChangeSupport
+- Extracted jDisco library to separate repository in January 2026
 
 ### Dependency Management
 
-Dependencies are managed via Gradle:
-- **jDisco 1.2.0** - Discrete event simulation library (from Maven local repository, Java 6)
+Dependencies are managed via Gradle with fallback strategy:
+- **jDisco 1.2.0** - Discrete event simulation library (external Maven dependency, Java 6 compatible)
+  - Repository: https://github.com/bedaHovorka/jdisco
+  - Published to GitHub Packages: `https://maven.pkg.github.com/bedaHovorka/jdisco`
+  - Fallback order: `mavenLocal()` (cache) → GitHub Packages → build fails
+  - Requires GitHub authentication for package download (see below)
 - **JUnit 5.11.4** - Testing framework (JUnit Jupiter API and Engine)
 - **AssertJ 3.27.6** - Fluent assertion library for better test readability
 - **Mockito 5.21.0** - Mocking framework
@@ -32,6 +37,22 @@ Gradle automatically downloads dependencies during the build. Configuration file
 - `settings.gradle.kts` - Project settings
 - `gradle.properties` - Version management and build properties
 
+**GitHub Packages Authentication:**
+
+To download jDisco from GitHub Packages, set these environment variables:
+```bash
+export GITHUB_ACTOR=your-github-username
+export GITHUB_TOKEN=your-personal-access-token
+```
+
+Or create `~/.gradle/gradle.properties`:
+```properties
+gpr.user=your-github-username
+gpr.key=your-personal-access-token
+```
+
+**Note:** In GitHub Actions CI/CD, authentication is automatic via `GITHUB_TOKEN`.
+
 ### Common Build Commands
 
 **Clean and build (includes tests and uber JAR):**
@@ -152,9 +173,17 @@ The project includes Docker support for both the Java application and LaTeX thes
 
 ### Common Docker Commands
 
-**Build both services:**
+**Build services:**
 ```bash
-docker compose build
+# Set GitHub credentials for jDisco download
+export GITHUB_ACTOR=your-github-username
+export GITHUB_TOKEN=your-personal-access-token
+
+# Build app (jDisco downloaded from GitHub Packages or uses local cache)
+docker compose build app
+
+# Build thesis
+docker compose build text
 ```
 
 **Run editor GUI:**
@@ -196,11 +225,14 @@ docker compose build app
 
 **Root Dockerfile (multi-stage build):**
 1. **Builder stage** - Uses Eclipse Temurin 21 JDK
-   - Builds jDisco dependency (Maven install, Java 6 compatibility)
-   - Resolves dependencies via Gradle (automatic download)
+   - Accepts GITHUB_ACTOR and GITHUB_TOKEN as build args
+   - Resolves dependencies via Gradle with fallback strategy:
+     - First tries mavenLocal() cache (if jDisco was built locally)
+     - Falls back to GitHub Packages (requires authentication)
    - Compiles Java sources (Java 21 target)
    - Runs all tests with JUnit 5 (build fails if tests fail)
    - Creates uber JAR with all dependencies
+   - Uses BuildKit cache mounts for ~/.m2, ~/.gradle for faster rebuilds
 2. **Runner stage** - Eclipse Temurin 21 JRE and X11 libraries
    - Minimal runtime environment
    - X11 forwarding for GUI support
@@ -257,10 +289,12 @@ If you encounter `java.awt.AWTError: Can't connect to X11 window server`:
 
 ### Artifacts
 
-Both services copy build outputs to `/artifacts` inside the container, which is mounted to `./artifacts/` on the host:
+Services copy build outputs to `/artifacts` inside the container, which is mounted to `./artifacts/` on the host:
 - `artifacts/app/interlockSim.jar` - Compiled application
 - `artifacts/text/bakalarka.pdf` - Compiled thesis
 
+**Note:** jDisco is now consumed as a Maven dependency from GitHub Packages, not built locally in Docker.
+
 ## Architecture
 
 ### Core Components
@@ -283,7 +317,7 @@ Both services copy build outputs to `/artifacts` inside the container, which is
 
 **Simulation engine:**
 - Built on jDisco library (discrete event simulation framework by Keld Helsgaun)
-- Standalone Maven module in `jdisco/` (Java 6 compatible)
+- External dependency from https://github.com/bedavs/jDisco (Java 6 compatible)
 - `sim/` package contains simulation processes (e.g., `ShuntingLoop`)
 
 **GUI:**
@@ -335,10 +369,10 @@ src/
     │       └── XMLContextFactoryTest.java
     └── resources/cz/vutbr/fit/interlockSim/xml/
         └── fixtures/              - Test XML files (10 fixtures)
-
-jdisco/                            - Third-party discrete event simulation library (Java 6, separate Maven module)
 ```
 
+**Note:** The jDisco library is now maintained as a separate project at https://github.com/bedavs/jDisco
+
 ## Code Style
 
 Follows `.editorconfig` configuration:
@@ -355,7 +389,7 @@ Follows `.editorconfig` configuration:
 2. **Tests must exist before modifications** - Any Java source file being modified MUST be covered by tests first. If tests don't exist, they must be written before making any changes
 3. **Minimal changes only** - Make only the specific changes requested, nothing more
 4. **No unsolicited modernization** - While the project now uses Java 21, do not update Java idioms to modern features, do not add new language features, do not restructure working code
-5. **jDisco preservation** - The jDisco module must remain at Java 6 compatibility and should never be modified
+5. **jDisco library** - jDisco is now maintained as a separate project. Do not modify jDisco code; report issues at https://github.com/bedavs/jDisco
 
 This is a working historical codebase from 2007. Stability and preservation are more important than modernization.
 
@@ -561,13 +595,13 @@ The project uses GitHub Actions for automated build, test, and deployment workfl
 **Workflow:** `.github/workflows/gradle-java21.yml`
 
 **Features:**
-- Builds jDisco library with Java 6 compatibility
 - Compiles main project with Java 21
 - Runs all tests with JUnit 5
 - Packages application JAR
 - Uploads JAR as artifact (90-day retention)
 - Smoke test execution
-- Dependency caching (Maven and Gradle) for faster builds
+- Dependency caching (Gradle) for faster builds
+- Requires jDisco 1.2.0 from Maven local repository
 
 **Triggers:**
 - Push to `main`, `develop`, `feature/**`, `fix/**` branches
@@ -878,9 +912,9 @@ cat docs/deprecated-api-report.md
 
 ### jDisco Library
 
-The jDisco library (Java 6 compatible) has **no deprecated API usage**. It should remain at Java 6 compatibility as designed.
+The jDisco library (Java 6 compatible) is now maintained as a separate project at https://github.com/bedavs/jDisco and has **no deprecated Java API usage**. It remains at Java 6 compatibility as designed.
 
-**Note:** This analysis is documentation-only. No code changes have been made. See `docs/deprecated-api-report.md` for detailed findings, migration strategies, and recommendations.
+**Note:** This analysis is documentation-only for the interlockSim codebase. See `docs/deprecated-api-report.md` for detailed findings about interlockSim. For jDisco deprecation analysis, see the jDisco repository.
 
 ## Future Development Considerations
 

Dockerfile

@@ -18,21 +18,16 @@
 # syntax=docker/dockerfile:1.4
 
 # ============================================
-# Stage 1: Reference pre-built jDisco image
-# ============================================
-# Build jdisco separately: docker compose build jdisco
-# This avoids duplicating jdisco/Dockerfile logic here
-FROM jdisco:latest AS jdisco-builder
-
-# ============================================
-# Stage 2: Build interlockSim with Gradle
+# Stage 1: Build interlockSim with Gradle
 # ============================================
 FROM eclipse-temurin:21-jdk AS builder
 
-WORKDIR /build/interlockSim
+# Build arguments for GitHub Packages authentication
+# These allow Gradle to download jDisco from GitHub Packages
+ARG GITHUB_ACTOR
+ARG GITHUB_TOKEN
 
-# Copy jDisco from previous stage (required dependency)
-COPY --from=jdisco-builder /root/.m2/repository/ /root/.m2/repository/
+WORKDIR /build/interlockSim
 
 # Layer 1: Copy Gradle wrapper files (cached until wrapper version changes)
 # These files are checked into git and ensure consistent Gradle version
@@ -48,8 +43,11 @@ COPY build.gradle.kts /build/interlockSim/
 
 # Layer 3: Resolve dependencies with BuildKit cache mount
 # Gradle caches: dependencies, build cache, and Gradle distributions
+# mavenLocal cache is also mounted for jDisco fallback
 RUN --mount=type=cache,target=/root/.gradle/caches \
     --mount=type=cache,target=/root/.gradle/wrapper \
+    --mount=type=cache,target=/root/.m2/repository \
+    GITHUB_ACTOR=${GITHUB_ACTOR} GITHUB_TOKEN=${GITHUB_TOKEN} \
     ./gradlew dependencies --no-daemon --warning-mode=summary
 
 # Layer 4: Copy source code
@@ -60,6 +58,8 @@ COPY src/ /build/interlockSim/src/
 # Tests run during build (haltOnFailure), creating uber JAR with shadowJar
 RUN --mount=type=cache,target=/root/.gradle/caches \
     --mount=type=cache,target=/root/.gradle/wrapper \
+    --mount=type=cache,target=/root/.m2/repository \
+    GITHUB_ACTOR=${GITHUB_ACTOR} GITHUB_TOKEN=${GITHUB_TOKEN} \
     ./gradlew clean build shadowJar --no-daemon --warning-mode=summary
 
 # Verify JAR was created
@@ -68,7 +68,7 @@ RUN ls -lh /build/interlockSim/build/libs/interlockSim.jar && \
     jar tf /build/interlockSim/build/libs/interlockSim.jar | head -20
 
 # ============================================
-# Stage 3: Runtime with JRE and X11 support
+# Stage 2: Runtime with JRE and X11 support
 # ============================================
 FROM eclipse-temurin:21-jre AS runner