Communication between a Java Agent and a C application with Legato


What is the best way of communication beween a Java Agent and a C application with Legato? We need the Java agent to call propietary AT commands inside a C application. Java Agent need sto call to the AT command inside the C application. What is the best way of doing this? We should use IPC and defining an IDL interface or there´s a better way?

Is there already a sample providing a similar functionality?



The recommended way of doing this with Legato is to write a small stub using JNI. The C-side of the stub is compiled as a stand-alone Legato component, allowing it to call Legato APIs. This stub then can be called from your Java application to get access (indirectly) to the Legato functionality.

Here’s a sample app which showing the technique (accessing the positioning & sms APIs from Java): (7.6 KB). The main Java application is in java-sample/JavaTest, and smsBridge and positioningBridge are the stubs.

Hope that helps.

Thank you kdunwoody

Case is a little more complex. We will use Java agent JNI to call Legato API libraries in “C”

We have
• One process A (Agent A) implementing a propietary AT commands and business logic.
• Sencond process B (Agent B) in charge of monitoring process and update of Agent A .

Attach the diagram

• Can we do calls to AT ad-hoc commands from process B so it´s process A the one sending the commands and receiving the answers as if it was a serial port behaviour?
• If it´s not possible, Can we use IPC to communicate both process? Is there any sample in Java?

Thank you

IsabelJava Agent.docx (49.8 KB)

I’m not sure about AT commands (not my area). Maybe you could open /dev/ttyAT from inside process B and send/receive commands that way?

Legato .api are the interface definitions for an IPC mechanism, so you can:

  1. create your own .api file defining the interface you need,
  2. implement the API in your C program (as described in, and then
  3. call it in your Java program (as shown in my sample).