RequestFactory Class Reference

A default request factory. More...

#include <mvIMPACT_acquire.h>

Public Member Functions
virtual Request *	createRequest (Device *, int)
virtual	~RequestFactory ()

Detailed Description

A default request factory.

Applications need to derive from this class and must re-implement the function mvIMPACT::acquire::RequestFactory::createRequest to work with custom objects derived from mvIMPACT::acquire::Request.

Deriving from mvIMPACT::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 mvIMPACT::acquire::Request class offered by this interface.

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

class MyRequestFactory;
 
//-----------------------------------------------------------------------------
// 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.
class MyRequest : public mvIMPACT::acquire::Request
//-----------------------------------------------------------------------------
{
  friend class MyRequestFactory;
  void init( void )
  {
    DeviceComponentLocator locator(getComponentLocator());
    locator.bindComponent( myRequestResult, "Result" );
  }
protected:
  explicit MyRequest( Device* pDev, int requestNr ) : Request(pDev, requestNr), myRequestResult()
  {
    init();
  }
public:
  explicit MyRequest( const MyRequest& src ) : Request(src), myRequestResult(src.myRequestResult) {}
  MyRequest& operator=( const MyRequest& rhs )
  {
    if( this != &rhs )
    {
      Request::operator=( rhs );
      init();
    }
    return *this;
  }
  PropertyIRequestResult myRequestResult;
};
 
//-----------------------------------------------------------------------------
// Example for a factory that creates 'MyRequest' instances
class MyRequestFactory : public mvIMPACT::acquire::RequestFactory
//-----------------------------------------------------------------------------
{
public:
  virtual mvIMPACT::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

//-----------------------------------------------------------------------------
void fn( mvIMPACT::acquire::Device* pDev )
//-----------------------------------------------------------------------------
{
  // ... some code ...
  MyRequestFactory mrf;
  FunctionInterface fi(pDev, &mrf);
  // ... more additional code
  // assuming we got back a request from the driver at this point:
  const Request* pRequest = fi.getRequest( getRequestNrFromSomewhere() );
  if( pRequest->isOK() )
  {
    const MyRequest* pMyRequest(dynamic_cast<const MyRequest*>(pRequest));
    cout << pMyRequest->myRequestResult.name() << ": " << pMyRequest->myRequestResult.readS() << endl;
    // do what you want to do with your derived request instance here!
  }
  // ... probably even more additional code
}

Since

1.12.56

Constructor & Destructor Documentation

~RequestFactory()

virtual ~RequestFactory ( )

inlinevirtual

Member Function Documentation

createRequest()

virtual Request * createRequest ( Device * , int  )

inlinevirtual