# Human readable name
name: Java CI

# Build on every push and pull request regardless of the branch
# Wiki: https://help.github.com/en/actions/reference/events-that-trigger-workflows
on:
    - push
    - pull_request

jobs:
  # job id
  build_and_test:

    # Environment image - always newest OS
    runs-on: ubuntu-latest

    # Run steps
    steps:
    # Pull changes
    - uses: actions/checkout@v2
    # Cache artifacts - however this has the downside that we don't get notified of
    # artifact resolution failures like invalid repository
    # Nevertheless the repositories should be more stable and it makes no sense to pull
    # a same version every time
    # A dry run would make more sense
    - uses: actions/cache@v1
      with:
        path: ~/.m2/repository
        key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
        restore-keys: |
          ${{ runner.os }}-maven-
    # Setup Java
    - name: Set up JDK
      uses: actions/setup-java@v1.3.0
      with:
        # Use Java 8, because it's minimum required version
        java-version: 8
    # Build and test (included in package)
    - name: Build with Maven and test
    # Run non-interactive, package (with compile+test),
    # ignore snapshot updates, because they are likely to have breaking changes, enforce checksums to validate posssible errors in depdendencies
      run: mvn --batch-mode package --no-snapshot-updates --strict-checksums --file pom.xml