jPipe - Justified Pipelines

The jPipe environment supports the definition of justification to support software maintenance activities. The name comes from "justified pipelines", as the key idea is to design an environment supporting the justification of CI/CD pipelines by design.

General Information

Principal Investigator:
- Sébastien Mosser, McSCert, McMaster University.
Active Contributors:
- Kalvin Thuan-Phong Khuu, McSCert, McMaster University. PhD Student.
Contributors:
- Nirmal Chaudhari, McSCert, McMaster University. Undergraduate Research Assistant.
- Aaron Loh, McSCert, McMaster University. Undergraduate Research Assistant.
- Deesha Patel, McSCert, McMaster University. Master Student.
- Corinne Pulgar, École de Technologie Supérieure (ETS). Master Student.

Repository organization

jpipe-lang: ANTLR4 grammar and generated lexer/parser
jpipe-model: domain model (justification elements, symbol table)
jpipe-operators: composition operator extension point and built-in operators
jpipe-compiler: compiler pipeline (parsing, model building, validation, export)
jpipe-cli: command-line interface and fat JAR entry point
docs: technical documentation and architecture decision records
homebrew: launcher script template for the Homebrew formula
debian: Debian source packaging metadata for the Ubuntu PPA

Developer Setup

Required tools

Tool	Version	Purpose
JDK	25	Compilation and runtime
Maven	3.x	Build tool
adr-tools	latest	Browsing and creating architecture decision records

Optional tools

Tool	Version	Purpose
MkDocs Material	latest	Previewing the documentation site locally (`mkdocs serve`)

Building

mvn package

The fat JAR is produced in jpipe-cli/target/.

Releasing a new version

Releases are triggered by pushing a v*.*.* tag to main. The pipeline creates a GitHub Release, updates the Homebrew formula, and uploads a Debian source package to the Ubuntu PPA.

Prerequisites: The following secrets must be configured in the GitHub repository settings:

Secret	Purpose
`HOMEBREW_TAP_TOKEN`	PAT with write access to `jpipe-mcscert/homebrew-mcscert`
`GPG_PRIVATE_KEY`	ASCII-armored GPG key registered on Launchpad
`GPG_KEY_ID`	Fingerprint of the signing key
`GPG_PASSPHRASE`	Passphrase for the signing key

Steps:

# 1. Verify the base version in pom.xml matches what you plan to tag.
#    pom.xml should be X.Y.Z-SNAPSHOT; the pipeline strips -SNAPSHOT automatically.
mvn verify   # confirm the build is green locally

# 2. Tag and push — the pipeline fires automatically.
git tag vX.Y.Z          # or vX.Y.Z-rcN for a pre-release
git push origin main --tags

# 3. After the pipeline completes, bump to the next development version.
mvn -B versions:set -DnewVersion=X.Y+1.0-SNAPSHOT -DgenerateBackupPoms=false
git commit -am "chore: bump to X.Y+1.0-SNAPSHOT"
git push origin main

What happens automatically:

The pipeline validates that the tag version matches the base version in pom.xml (e.g. tag v2.1.0 is accepted when pom.xml declares 2.1.0-SNAPSHOT).
mvn versions:set is run inside the pipeline to stamp the exact release version into the fat JAR manifest (Implementation-Version: X.Y.Z).
A GitHub Release is created with the fat JAR and a Homebrew tarball. Tags containing - (e.g. -rc1) are automatically marked as pre-releases.
jpipe.rb in the Homebrew tap is updated with the new URL and SHA256 (stable releases only — skipped for pre-releases).
A signed Debian source package is uploaded to ppa:mcscert/ppa (stable releases only — skipped for pre-releases).

Verifying the release (~30 min after the pipeline completes):

# macOS
brew tap jpipe-mcscert/mcscert
brew install jpipe

# Ubuntu
sudo add-apt-repository ppa:mcscert/ppa
sudo apt update && sudo apt install jpipe

Code style

Formatting is enforced by Spotless (Google Java Format) and Checkstyle. To auto-format before committing:

mvn spotless:apply

Build output / shade warnings

The fat JAR build (jpipe-cli) merges many dependencies and would normally emit overlap warnings from the Maven Shade plugin. These are suppressed by default via .mvn/jvm.config. To re-enable them for a single run:

mvn package -Dorg.slf4j.simpleLogger.log.org.apache.maven.plugins.shade.DefaultShader=warn

Usage

Running the compiler

After building, the fat JAR is at jpipe-cli/target/jpipe-cli-*.jar. The process subcommand is the default, so these two invocations are equivalent:

java -jar jpipe-cli/target/jpipe-cli-*.jar -i my.jd -d MyModel -f dot
java -jar jpipe-cli/target/jpipe-cli-*.jar process -i my.jd -d MyModel -f dot

Common flags

Flag	Short	Description
`--input FILE`	`-i`	Input `.jd` source file (default: stdin)
`--output FILE`	`-o`	Output file (default: stdout)
`--diagram NAME`	`-d`	Name of the model to export (required)
`--format FORMAT`	`-f`	Output format — see table below (default: `JPIPE`)
`--headless`		Suppress the logo banner
`--log-level LEVEL`		Log verbosity: `OFF` `ERROR` `WARN` `INFO` `DEBUG` `TRACE`

Output formats

Format	Description	Requires Graphviz
`JPIPE`	Canonical jPipe source (round-trip)	No
`DOT`	Graphviz DOT source	No
`PNG`	Rendered PNG image	Yes
`JPEG`	Rendered JPEG image	Yes
`SVG`	Rendered SVG image	Yes
`JSON`	JSON model dump	No
`PYTHON`	Python object model	No

Install Graphviz and run jpipe doctor to verify that the dot binary is on your PATH before using image formats.

Other subcommands

# Parse and validate without exporting — prints diagnostics, statistics, and the symbol table
java -jar jpipe-cli/target/jpipe-cli-*.jar diagnostic -i my.jd

# Check runtime dependencies (Graphviz)
java -jar jpipe-cli/target/jpipe-cli-*.jar doctor

Minimal `.jd` example

justification MyModel {
    conclusion  c  is "Our claim"
    strategy    s  is "Argument"
    evidence    e1 is "Evidence A"
    evidence    e2 is "Evidence B"

    s  supports c
    e1 supports s
    e2 supports s
}

Compile it to a DOT diagram:

java -jar jpipe-cli/target/jpipe-cli-*.jar -i my.jd -d MyModel -f dot -o my.dot
dot -Tpng my.dot -o my.png

More examples are in the examples/ directory.

How to cite?

@software{mcscert:jpipe,
  author = {Mosser, Sébastien and Khuu, Kalvin Thuan-Phong and Chaudhari, Nirmal and Loh, Aaron and Patel, Deesha and Pulgar, Corinne},
  license = {MIT},
  title = {{jPipe}},
  url = {https://github.com/jpipe-mcscert/jpipe-compiler}
}

How to contribute?

Found a bug, or want to add a cool feature? Feel free to fork this repository and send a pull request.

If you're interested in contributing to the research effort related to jPipe, feel free to contact the PI: Dr. Sébastien Mosser.

We do have undergrad summer internships available to contribute to the compiler, as well as MASc and PhD positions in Software Engineering at Mac.

AI assistance policy

Parts of this codebase were developed with the assistance of Claude (Anthropic), an AI coding assistant. We are transparent about this use and welcome AI-assisted contributions, subject to the following conditions:

Pull requests must not be 100% AI-generated. Every contribution must reflect the understanding and judgement of a human author.
Human authors are fully responsible for the correctness, quality, and appropriateness of their contributions, regardless of whether AI tools were used in their preparation.
Reviewers may ask contributors to explain any part of their submission.