7. Ping Pong Example

A simple ping pong example is provided to demonstrate the basic capabilities of the MATLAB DDS integration.

The ping pong example can be found in the following directory:

OSPL_HOME/tools/matlab/examples/matlab/pingpong

The ping pong example creates two participants.

  1. A pinger that writes to the PING partition and reads from the PONG partition.

  2. A ponger that writes to the PONG partition and reads from the PING partition.

A matlab script is provided that writes and reads sample data in the pinger and ponger participants.

7.1. Example Files

Files with the .m extension are MATLAB script files.

An explanation of what each example file does is provided below.

pingpong.idl

  • Defines the PingPongType in idl

  • Used to generate the MATLAB file PingPongType.m via:

idlpp -l matlab pingpong.idl

PingPongType.m

  • Defines a PingPongType; generated from idlpp

  • The PingPongType represents a DDS topic type.

  • PingPongType specifies two properties: id, count.

DDS_PingerVolatileQoS.xml

  • XML file that specifies the DDS QoS (quality of service) settings for pinger.

DDS_PongerVolatileQoS.xml

  • XML file that specifies the DDS QoS (quality of service) settings for ponger.

setup_pinger.m

  • Creates the pinger participant on the default DDS domain, with specified QoS profile.

  • Creates the topic PingPongType.

  • Creates the publisher using the domain participant on the PING partition specified in the specified QoS profile.

  • Creates the writer using the publisher and the specified QoS profile.

  • Creates the subscriber using the domain participant on the PONG partition specified in the QoS profile.

  • Creates the reader using the subscriber and the specified QoS profile.

setup_ponger.m

  • Creates the ponger participant on default domain with specified QoS profile.

  • Creates the topic PingPongType.

  • Creates the publisher using the domain participant on the PONG partition specified in the QoS profile.

  • Creates the writer using the publisher and the specified QoS profile.

  • Creates the subscriber using the domain participant on the PING partition specified in the QoS profile.

  • Creates the reader using the subscriber and the specified QoS profile.

pinger_ponger.m

  • MATLAB script that writes and reads sample data in the pinger and ponger participants.

  • This script calls the setup_pinger.m and setup_ponger.m scripts.

  • This is the main script to run the ping pong example.

  • This script is run from the MATLAB Command Window.

7.2. Steps to run example

  1. In the MATLAB command window, run pinger_ponger.m.

    • Type “pinger_ponger”.

    • Hit enter.