IRequestFactory Interface Reference

A default request factory. More...

Public Member Functions
Request	createRequest (Device device, int requestNr)

Detailed Description

A default request factory.

Applications need to derive from this class and must re-implement the function mv.impact.acquire.IRequestFactory.createRequest to work with custom objects derived from mv.impact.acquire.Request.

Deriving from mv.impact.acquire.Request can be useful when a certain device driver or device offers a custom feature that is returned as part of the request object that can not be accessed using the mv.impact.acquire.Request class offered by this interface.

Example

This shows how a request factory could be used to create custom request objects from within a mv.impact.acquire.FunctionInterface instance.

//-----------------------------------------------------------------------------
// Example for a derived request object. It doesn't introduce new functionality
// but rebinds an existing property. Custom properties could bound in a similar
// way.
public class MyRequest : Request
//-----------------------------------------------------------------------------
{
  private void init()
  {
    DeviceComponentLocator locator = getComponentLocator();
    locator.bindComponent(myRequestResult, "Result");
  }
  public MyRequest(Device pDev, int requestNr)
     : base(pDev, requestNr)
  {
    init();
  }
  public readonly EnumPropertyI<TRequestResult> myRequestResult = new EnumPropertyI<TRequestResult>();
}
 
public class MyRequestFactory : IRequestFactory
{
  public mv.impact.acquire.Request createRequest(Device pDev, int requestNr) { return new MyRequest(pDev, requestNr); }
}

Now the request factory must be passed to the constructor of the function interface

//-----------------------------------------------------------------------------
public void fn( mv.impact.acquire.Device pDev )
//-----------------------------------------------------------------------------
{
  // ... some code ...
  MyRequestFactory mrf = new MyRequestFactory();
  FunctionInterface fi = new FunctionInterface(pDev, mrf);
  // ... more additional code
  // assuming we got back a request from the driver at this point:
  Request pRequest = fi.getRequest( getRequestNrFromSomewhere() );
  if( pRequest.isOK )
  {
    MyRequest pMyRequest = (MyRequest)pRequest;
    Console.WriteLine( "{0}: {1}", pMyRequest.myRequestResult.name, pMyRequest.myRequestResult.readS() );
  }
  // ... probably even more additional code
}

Since

1.12.56

Member Function Documentation

createRequest()

Request createRequest	(	Device	device,
		int	requestNr )

Parameters

[in]	device	A pointer to a mv.impact.acquire.Device object obtained from a mv.impact.acquire.DeviceManager object.
[in]	requestNr	The request number that internally has been assigned to this request by the device driver.