Java ZMQ Remote API

[lumeqi]

Thank you, I can only create one sim. I have previously tried to control the opening and closing of the gripper through "setInt32Signal" and it was successful. But I don't know how to pass a callback function when using sim.moveToConfig.

In Example.java, I saw registering a callback function, but I didn't find out how to use it.

[lumeqi]

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public class Example {
    public Example() {
    }

    public static Object[] myFunc(Object[] items) {
        Object[] retVals = new Object[]{21};
        return retVals;
    }

    public static void main(String[] _args) throws IOException, CborException {
        RemoteAPIClient client = new RemoteAPIClient();
        RemoteAPIObjects._sim sim = client.getObject().sim();
        client.registerCallback("myFunc", Example::myFunc);
        sim.setStepping(new Object[]{true});
        sim.startSimulation(new Object[0]);
        double simTime = 0.0;

        while((simTime = sim.getSimulationTime(new Object[0])) < 3.0) {
            System.out.printf("Simulation time: %.2f [s]%n", simTime);
            sim.step(new Object[0]);
        }

        sim.stopSimulation(new Object[0]);
    }
}

I know

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client.registerCallback("myFunc", Example::myFunc);

used to register a callback, but where was this callback function called?
Sorry, I have another question. Does the callback function have to return data of type "Object []" and what is the meaning of this data.

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client.registerCallback("configCallBack", ConfigCallBack::onCallBack);

sim.moveToConfig(
        -1, currentConfig, currentV, currentA,
        vel, accel, jerk,
        configs, targetV,
        ??, data, cyclicJoints, 0.0
);

If ConfigCallBack is the class I defined and onCallBack is the callback function in the class I defined, what should I write in the "??" position in my code? Thanks.

[fferri]

Make sure to use the latest version of CoppeliaSim. You are using an old version.

In the latest version of Example.java there are more examples.

About your other question: Object[] is an array of Object which is the superclass of all types, indicating a no better specified type.
Object[] is used as a return argument in Java as it is the only way to return multiple values from a function.

[lumeqi]

Thanks! I'm sorry to bother you again. I saw the code for calling the callback function:

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Long retVal = sim.testCB(21,"myFunc@func",42); // sim.testCB is calling back above "myFunc"

But may this method not be used for parameter passing? Because the sim.testCB method returns a value of type Long, when I write code like this, I get an error:

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Java. lang. RuntimeException: C:/.../lua/sim.lua: 712: attempt to call a number value (local 'callback')

My code (Where "configs" and "joints" are the parameters I passed.):

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client.registerCallback("configCallBack", ConfigCallBack::onCallBack);
sim.moveToConfig(
                -1, currentConfig, currentV, currentA,
                vel, accel, jerk,
                configs, targetV,
                sim.testCB(configs, "configCallBack@func", joints), joints, cyclicJoints, 0.0
        );

Perhaps the sim.testCB function can only be called directly and cannot be passed as a parameter. So what should I do? (I have downloaded and checked the latest version of the code)

[lumeqi]

I found a solution in the source code, and I should pass the callback function as a parameter as follows:

Code: Select all

sim.moveToConfig(
                -1, currentConfig, currentV, currentA,
                vel, accel, jerk,
                configs, targetV,
                "configCallBack@func", joints, cyclicJoints, 0.0
        );

I tried to write it as "configCallBack" before, but it failed. It seems to be because the suffix "@func" needs to be added.