I would like to use the MMDevice API from my Java app. What are my options?

I tried to use JNA. Looks like I can't use JNA Typelib parsing because there no types for this API (Is there a COM type library for Windows Core Audio). As suggested, I need to provide my own declarations of the API.

So I also tried both JNA examples with manual declarations but they give "Interface not supported HRESULT=80004002" error:

public class MMDeviceAPITest {
    public static void test1() {
        try {
            Ole32.INSTANCE.CoInitializeEx(Pointer.NULL, Ole32.COINIT_MULTITHREADED);
            var obj = new Test1.MMDeviceEnumerator();  // exception E_NOINTERFACE (HRESULT: 80004002)
            // ...
        } finally {
            Ole32.INSTANCE.CoUninitialize();
        }
    }
    public static void test2() {
        try {
            Ole32.INSTANCE.CoInitializeEx(Pointer.NULL, Ole32.COINIT_MULTITHREADED);
            var factory = new Factory();
            var obj = factory.createObject(Test2.MMDeviceEnumerator.class);  // exception E_NOINTERFACE (HRESULT: 80004002)
            var in = obj.queryInterface(Test2.IMMDeviceEnumerator.class);
            // ...
        } finally {
            Ole32.INSTANCE.CoUninitialize();
        }
    }
}

interface Test1 {
    class MMDeviceEnumerator extends COMLateBindingObject {
        public MMDeviceEnumerator() {
            super(new Guid.CLSID("bcde0395-e52f-467c-8e3d-c4579291692e"), true);
        }
    }
}

interface Test2 {
    @ComObject(clsId = "bcde0395-e52f-467c-8e3d-c4579291692e")
    interface MMDeviceEnumerator extends IUnknown {}  // doesn't extend IUnknown in C sources, probably it's the problem...
    @ComInterface(iid = "a95664d2-9614-4f35-a746-de8db63617e6")
    interface IMMDeviceEnumerator extends IUnknown {}
}

Any ideas how I could access this API from Java? Can I somehow create working declarations for JNA? Or use another framework maybe?

My last idea is to create/find a micro native app/library that wraps the needed COM calls, so I could call this app/library easily (via subprocesses or simple JNA declarations). I'm new to COM world, but it sounds working for me...

CodePudding user response：

The docs you linked show how to create using CoCreateInstance:

const CLSID CLSID_MMDeviceEnumerator = __uuidof(MMDeviceEnumerator);
const IID IID_IMMDeviceEnumerator = __uuidof(IMMDeviceEnumerator);
hr = CoCreateInstance(
       CLSID_MMDeviceEnumerator, NULL,
       CLSCTX_ALL, IID_IMMDeviceEnumerator,
       (void**)&pEnumerator);

This should get you somewhere close with JNA. I made some changes from the implementation of IWbemContext in JNA.

class MMDeviceEnumerator extends Unknown {
    public static final CLSID CLSID_MMDeviceEnumerator = new CLSID("bcde0395-e52f-467c-8e3d-c4579291692e");
    public static final GUID IID_IMMDeviceEnumerator = new GUID("a95664d2-9614-4f35-a746-de8db63617e6");

    public MMDeviceEnumerator(Pointer p) {
        super(p);
    }

    public static MMDeviceEnumerator create() {
        PointerByReference pEnumerator = new PointerByReference();

        HRESULT hres = Ole32.INSTANCE.CoCreateInstance(
            CLSID_MMDeviceEnumerator, null,
            WTypes.CLSCTX_ALL, IID_IMMDeviceEnumerator, pEnumerator);
        if (COMUtils.FAILED(hres)) {
            return null;
        }

        return new MMDeviceEnumerator(pEnumerator.getValue());
    }

    // map functions as needed
}

CodePudding user response：

For some reason I can't suggest edits to the answer of Daniel Widdis. The answer worked for me, many thanks! Just wanted to show how to map one method as an example:

class MMDeviceEnumerator extends Unknown {
    public static final CLSID CLSID_MMDeviceEnumerator = new CLSID("bcde0395-e52f-467c-8e3d-c4579291692e");
    public static final GUID IID_IMMDeviceEnumerator = new GUID("a95664d2-9614-4f35-a746-de8db63617e6");

    public MMDeviceEnumerator(Pointer p) {
        super(p);
    }

    public static MMDeviceEnumerator create() {
        PointerByReference pEnumerator = new PointerByReference();

        HRESULT hres = Ole32.INSTANCE.CoCreateInstance(
            CLSID_MMDeviceEnumerator, null,
            WTypes.CLSCTX_ALL, IID_IMMDeviceEnumerator, pEnumerator);
        if (COMUtils.FAILED(hres)) {
            return null;
        }

        return new MMDeviceEnumerator(pEnumerator.getValue());
    }

    public static final int EDataFlow_eRender = 0;
    public static final int EDataFlow_eCapture = 1;
    public static final int EDataFlow_eAll = 2;
    public static final int EDataFlow_enum_count = 3;

    public static final int DEVICE_STATE_ACTIVE = 0x1;
    public static final int DEVICE_STATE_DISABLED = 0x2;
    public static final int DEVICE_STATE_NOTPRESENT = 0x4;
    public static final int DEVICE_STATE_UNPLUGGED = 0x8;
    public static final int DEVICE_STATEMASK_ALL = 0xF;

    public void EnumAudioEndpoints(int dataFlow, int dwStateMask, PointerByReference ppDevices) {
        WinNT.HRESULT res = (WinNT.HRESULT) _invokeNativeObject(
            3,  // `EnumAudioEndpoints` is the 3rd method of `IMMDeviceEnumeratorVtbl` in `mmdeviceapi.h`
            new Object[] { getPointer(), dataFlow, new WinDef.DWORD(dwStateMask), ppDevices},
            WinNT.HRESULT.class
        );
        COMUtils.checkRC(res);
    }

    // map other functions as needed
}