Federate xAPI

Federate xAPI is an HLA Federate that joins an existing Run-Time Infrastructure (RTI), subscribes to configured HLA objects and interactions, detects defined state changes, applies filtering and mapping rules, and sends resulting xAPI statements to a Learning Record Store. A supporting SQL cache maintains selected federation state for correlation and contextual enrichment. The architecture preserves HLA for simulation execution while introducing a standards-based activity-data layer for downstream analysis.

Configuration

The Federate uses multiple sources of configuration including a Simulation.config file and a json config file for configuring resulting xAPI.

Simulation Config

To connect to an HLA Federation, you will want to update the config/Simulation.config files (or config/Simulation.pitch.config if running in pitch mode). You will update the following fields to reflect the Federation details and also point to the appropriate FOM:

localSettingsDesignator=
federationName=HlaFedereplSimulation
federateName=Federate xAPI

fom=config/HlaFedereplFOM.xml

xAPI Config

The sample config/xapi-config.json reflects the current state of compatible configuration options. See the HLA xAPI Adapter xAPI Configuration Reference for a full configuration reference.

Database Config

The application runs on an embedded SQLite database by default but there are other options. See the database config docs for more info.

Queue Config

The application runs on an embedded ActiveMQ Artemis for queueing and decoupling. See the queue config docs for more info.

Vendoring Portico

make lib rebuilds and vendors only Portico's Java jar into this repository's local Maven file repository. Portico ships its own Ant wrapper at codebase/ant, so no separate Ant installation is required.

The vendoring script intentionally uses a Java-only Portico Ant build file. On Linux, Portico's full build.xml imports C++ profiles that are not needed for this project and can fail during Ant parsing with a duplicate cpp.hla13.compile target before any Java compilation begins.

To Run

The build output does not bundle an RTI implementation. The development runtime targets add either the vendored Portico RTI jar or a local Pitch RTI install on the runtime classpath.

You will need to update config/Simulation.config with the appropriate federation information, and reference the file of the target federation's FOM.

To build and run federate once configured:

make clean build
make run-rti # if you would like to run a Portico RTI, do this and then open a new terminal for the next line
make run-dev

To run against a Pitch RTI installation instead of Portico:

make clean build
PITCH_RTI_LIB="/path/to/prti1516e/lib/*" \
make run-dev-pitch

Development Checks

Use Maven's verify lifecycle before opening a PR:

make verify

This runs unit tests, builds the package, and fails if linting or formatting checks do not pass. Note that the tests require docker to run.

The PostgreSQL object-cache contract tests use Testcontainers and require a working Docker-compatible container runtime. The test suite starts and removes its own PostgreSQL 17 container; no manually configured database is needed.

To run only linting locally:

make lint

To update formatting locally:

make format

Project style is intentionally minimal: Java uses 4-space indentation, no wildcard imports, braces on control statements, UTF-8 text, LF line endings, final newlines, and no trailing whitespace. Make recipes keep required tab indentation.

License

Distributed under the Apache License version 2.0.

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