# ros2_java_examples

**Repository Path**: ros_java/ros2_java_examples

## Basic Information

- **Project Name**: ros2_java_examples
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-08-21
- **Last Updated**: 2021-08-21

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# ROS2 Java examples

This is a collection of examples that use the Java bindings for ROS2. They aim to mimic the rclcpp examples, but using the [ROS2 Java](https://github.com/esteve/ros2_java) bindings. Please follow the instructions on https://github.com/esteve/ros2_java/blob/master/README.md#desktop to build the ROS2 Java bindings, you can try out any of the following examples via the `ros2` command line tool:

```sh
. ~/ament_ws/install_isolated/local_setup.sh
. ~/ros2_java_ws/install_isolated/local_setup.sh
ros2 run PACKAGE_NAME SCRIPT_NAME
```

For example, to run the `PublisherLambda` and `SubscriberLambda` examples, open two terminals and type this on one of them to run the subscriber example:

```sh
. ~/ament_ws/install_isolated/local_setup.sh
. ~/ros2_java_ws/install_isolated/local_setup.sh
ros2 run rcljava_examples subscriber_lambda
```

and the following to run the publisher examples on the other terminal:

```sh
. ~/ament_ws/install_isolated/local_setup.sh
. ~/ros2_java_ws/install_isolated/local_setup.sh
ros2 run rcljava_examples publisher_lambda
```

you should now see a bunch of messages showing up on the first terminal. A list of all the scripts that can be run can be found in https://github.com/esteve/ros2_java_examples/blob/master/rcljava_examples/build.gradle#L28-L46

Alternatively, you can also run the examples by invoking the `java` command and the fully-qualified name of the class you wan to run. For example, type the following for running the `SubscriberLambda` example:

```sh
. ~/ros2_java_ws/install_isolated/local_setup.sh
java org.ros2.rcljava.examples.subscriber.SubscriberLambda
```

and this for the `PublisherLambda` example:

```sh
. ~/ros2_java_ws/install_isolated/local_setup.sh
java org.ros2.rcljava.examples.publisher.PublisherLambda
```

## Publisher

- [PublisherNotComposable](rcljava_examples/src/main/java/org/ros2/rcljava/examples/publisher/PublisherNotComposable.java). An old-style publisher, resembling the ROS1 API.
- [PublisherLambda](rcljava_examples/src/main/java/org/ros2/rcljava/examples/publisher/PublisherLambda.java). A composable publisher that uses a lambda function and a timer to publish `std_msgs.msg.String` messages.
- [PublisherMemberFunction](rcljava_examples/src/main/java/org/ros2/rcljava/examples/publisher/PublisherMemberFunction.java). A composable publisher that uses a member function and a timer to publish `std_msgs.msg.String` messages.

## Subscriber

- [SubscrberNotComposable](rcljava_examples/src/main/java/org/ros2/rcljava/examples/subscriber/SubscriberNotComposable.java). An old-style subscriber, resembling the ROS1 API.
- [SubscriberLambda](rcljava_examples/src/main/java/org/ros2/rcljava/examples/subscriber/SubscriberLambda.java). A composable subscriber that uses a lambda function to process `std_msgs.msg.String` messages.
- [SubscriberMemberFunction](rcljava_examples/src/main/java/org/ros2/rcljava/examples/subscriber/SubscriberMemberFunction.java). A composable subscriber that uses a member function to process `std_msgs.msg.String` messages.

## Composition

- [PublisherNode](rcljava_examples/src/main/java/org/ros2/rcljava/examples/composition/PublisherNode.java). A composable publisher node that can be reused standalone or as part of a multi-node program.
- [SubscriberNode](rcljava_examples/src/main/java/org/ros2/rcljava/examples/composition/SubscriberNode.java). A composable subscriber node that can be reused standalone or as part of a multi-node program.
- [Composed](rcljava_examples/src/main/java/org/ros2/rcljava/examples/composition/Composed.java). A multi-node program that runs both a `SubscriberNode` and a `PublisherNode`.

## Timer

- [TimerLambda](rcljava_examples/src/main/java/org/ros2/rcljava/examples/timer/TimerLambda.java). A timer that calls a lambda function to print out a message to the console repeatedly.
- [TimerMemberFunction](rcljava_examples/src/main/java/org/ros2/rcljava/examples/timer/TimerMemberFunction.java). A timer that calls a member function to print out a message to the console repeatedly.

## Service

- [AddTwoIntsService](rcljava_examples/src/main/java/org/ros2/rcljava/examples/service/AddTwoIntsService.java). A service that will return the sum of two integers.

## Client

- [AddTwoIntsClient](rcljava_examples/src/main/java/org/ros2/rcljava/examples/client/AddTwoIntsClient.java). A client that will submit a request to the [AddTwoIntsService](rcljava_examples/src/main/java/org/ros2/rcljava/examples/service/AddTwoIntsService.java) to sum two integers.