ROS 2 Java client library

Build status

Target	Status
ROS Galactic - Ubuntu Focal (OpenJDK)

Introduction

This is a set of projects (bindings, code generator, examples and more) that enables developers to write ROS 2 applications for the JVM and Android.

Besides this repository itself, there’s also:

• https://github.com/ros2-java/ament_java, which adds support for Gradle to Ament
• https://github.com/ros2-java/ament_gradle_plugin, a Gradle plugin that makes it easier to use ROS 2 in Java and Android project. The Gradle plugin can be installed from Gradle Central https://plugins.gradle.org/plugin/org.ros2.tools.gradle
• https://github.com/ros2-java/ros2_java_examples, examples for the Java Runtime Environment
• https://github.com/ros2-java/ros2_android_examples, examples for Android

Is this Java only?

No, any language that targets the JVM can be used to write ROS 2 applications.

Including Android?

Yep! Make sure to use Fast-RTPS as your DDS vendor and at least this revision.

Features

The current set of features include:

• Generation of all builtin and complex ROS types, including arrays, strings, nested types, constants, etc.
• Support for publishers and subscriptions
• Tunable Quality of Service (e.g. lossy networks, reliable delivery, etc.)
• Clients and services
• Timers
• Composition (i.e. more than one node per process)
• Time handling (system and steady, ROS time not yet supported https://github.com/ros2-java/ros2_java/issues/122)
• Support for Android
• Parameters services and clients (both asynchronous and synchronous)

Sounds great, how can I try this out?

Install dependencies

Note: While the following instructions use a Linux shell the same can be done on other platforms like Windows with slightly adjusted commands.

1. Install ROS 2.

2. Install Java and a JDK.

   On Ubuntu, you can install OpenJDK with:

    sudo apt install default-jdk
   

3. Install Gradle. Make sure you have Gradle 3.2 (or later) installed.

   Ubuntu Bionic or later

    sudo apt install gradle
   

   macOS

    brew install gradle
   

   Note: if run into compatibily issues between gradle 3.x and Java 9, try using Java 8,

    brew tap caskroom/versions
    brew cask install java8
    export JAVA_HOME=/Library/Java/JavaVirtualMachines/1.8.0.jdk/Contents/Home
   

   Windows

    choco install gradle
   

4. Install build tools:

    sudo apt install curl python3-colcon-common-extensions python3-pip python3-vcstool
   

5. Install Gradle extensions for colcon:

    python3 -m pip install -U git+https://github.com/colcon/colcon-gradle
    python3 -m pip install --no-deps -U git+https://github.com/colcon/colcon-ros-gradle
   

Download and Build ROS 2 Java for Desktop

1. Source your ROS 2 installation, for example:

    source /opt/ros/galactic/setup.bash
   

2. Download the ROS 2 Java repositories into a workspace:

    mkdir -p ros2_java_ws/src
    cd ros2_java_ws
    curl -skL https://raw.githubusercontent.com/ros2-java/ros2_java/main/ros2_java_desktop.repos | vcs import src
   

3. Linux only Install ROS dependencies:

    rosdep install --from-paths src -y -i --skip-keys "ament_tools"
   

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Contributing to ROS 2 Java

This document contains rules and guidelines for contributing to the ROS 2 Java project.

How to contribute

Here are a few things you can do to contribute to the project:

1. Report a bug by opening an issue on GitHub
2. Even better, open a pull request fixing the bug!

If you open a ticket, be patient while waiting for a response; The ROS 2 Java team is small. While you wait, other excellent ways to contribute include:

1. Leave constructive feedback on an open pull request
2. Try to reproduce an existing bug report and leave a comment

Pull requests

Each pull request must satisfy the following requirements before it can be merged:

1. Target the latest developement branch (main)
2. Have one approval from a maintainer
3. Continuous integration (CI) is building and passing tests
   • This should be automatically triggered upon opening a pull request

Note about license

Any contribution that you make to this repository will be under the Apache 2 License, as dictated by that license:

5. Submission of Contributions. Unless You explicitly state otherwise,
   any Contribution intentionally submitted for inclusion in the Work
   by You to the Licensor shall be under the terms and conditions of
   this License, without any additional terms or conditions.
   Notwithstanding the above, nothing herein shall supersede or modify
   the terms of any separate license agreement you may have executed
   with Licensor regarding such Contributions.