Example access to other components#

Access to other components is really simple.

Example

#include <iostream>
#include <stdexcept>

#include "example_interfaces.h"

#include <support/component_impl.h>

class CAccessComponent
    : public sdv::CSdvObject
    , public IShowExample
{
public:
    CAccessComponent()
    {
        m_HelloInterface = sdv::core::GetObject("Hello_Component").GetInterface<ISayHello>();

        sdv::TInterfaceAccessPtr helloComp = sdv::core::GetObject("Hello_Component");
        m_GoodbyeInterface = helloComp.GetInterface<ISayGoodbye>();

        if (!m_HelloInterface || !m_GoodbyeInterface)
        {
            throw std::runtime_error("Could not get all needed interfaces!");
        }
    }

    BEGIN_SDV_INTERFACE_MAP()
        SDV_INTERFACE_ENTRY(IShowExample)
    END_SDV_INTERFACE_MAP()

    DECLARE_OBJECT_CLASS_NAME("Access_Component")
    DECLARE_OBJECT_CLASS_TYPE(sdv::EObjectType::BasicService);
    
    /**
    * @brief Show messages, implements the function of IShowExample
    */
    void Show() override
    {
        m_HelloInterface->SayHello();
        m_GoodbyeInterface->SayGoodbye();
    }

private:
    ISayHello *   m_HelloInterface   = nullptr;
    ISayGoodbye * m_GoodbyeInterface = nullptr;
};

DEFINE_SDV_OBJECT(CAccessComponent)

Store Interfaces

#include <iostream>
#include <stdexcept>

#include "example_interfaces.h"

#include <support/component_impl.h>

class CAccessComponent
    : public sdv::CSdvObject
    , public IShowExample
{
public:
    CAccessComponent()
    {
        m_HelloInterface = sdv::core::GetObject("Hello_Component").GetInterface<ISayHello>();

        sdv::TInterfaceAccessPtr helloComp = sdv::core::GetObject("Hello_Component");
        m_GoodbyeInterface = helloComp.GetInterface<ISayGoodbye>();

        if (!m_HelloInterface || !m_GoodbyeInterface)
        {
            throw std::runtime_error("Could not get all needed interfaces!");
        }
    }

    BEGIN_SDV_INTERFACE_MAP()
        SDV_INTERFACE_ENTRY(IShowExample)
    END_SDV_INTERFACE_MAP()

    DECLARE_OBJECT_CLASS_NAME("Access_Component")
    DECLARE_OBJECT_CLASS_TYPE(sdv::EObjectType::BasicService);
    
    /**
    * @brief Show messages, implements the function of IShowExample
    */
    void Show() override
    {
        m_HelloInterface->SayHello();
        m_GoodbyeInterface->SayGoodbye();
    }

private:
    ISayHello *   m_HelloInterface   = nullptr;
    ISayGoodbye * m_GoodbyeInterface = nullptr;
};

DEFINE_SDV_OBJECT(CAccessComponent)

When interfaces are needed for more than a one-time use it is a good idea to store them in member variables to reduce the overhead of fetching the interface.

Get Object by Name

#include <iostream>
#include <stdexcept>

#include "example_interfaces.h"

#include <support/component_impl.h>

class CAccessComponent
    : public sdv::CSdvObject
    , public IShowExample
{
public:
    CAccessComponent()
    {
        m_HelloInterface = sdv::core::GetObject("Hello_Component").GetInterface<ISayHello>();

        sdv::TInterfaceAccessPtr helloComp = sdv::core::GetObject("Hello_Component");
        m_GoodbyeInterface = helloComp.GetInterface<ISayGoodbye>();

        if (!m_HelloInterface || !m_GoodbyeInterface)
        {
            throw std::runtime_error("Could not get all needed interfaces!");
        }
    }

    BEGIN_SDV_INTERFACE_MAP()
        SDV_INTERFACE_ENTRY(IShowExample)
    END_SDV_INTERFACE_MAP()

    DECLARE_OBJECT_CLASS_NAME("Access_Component")
    DECLARE_OBJECT_CLASS_TYPE(sdv::EObjectType::BasicService);
    
    /**
    * @brief Show messages, implements the function of IShowExample
    */
    void Show() override
    {
        m_HelloInterface->SayHello();
        m_GoodbyeInterface->SayGoodbye();
    }

private:
    ISayHello *   m_HelloInterface   = nullptr;
    ISayGoodbye * m_GoodbyeInterface = nullptr;
};

DEFINE_SDV_OBJECT(CAccessComponent)

With the sdv::core::GetObject function one gets the sdv::core::IInterfaceAccessPtr of the object with the given name (see the Object Name highlight at How to create a general VAPI Component).

Get Interface by Type

#include <iostream>
#include <stdexcept>

#include "example_interfaces.h"

#include <support/component_impl.h>

class CAccessComponent
    : public sdv::CSdvObject
    , public IShowExample
{
public:
    CAccessComponent()
    {
        m_HelloInterface = sdv::core::GetObject("Hello_Component").GetInterface<ISayHello>();

        sdv::TInterfaceAccessPtr helloComp = sdv::core::GetObject("Hello_Component");
        m_GoodbyeInterface = helloComp.GetInterface<ISayGoodbye>();

        if (!m_HelloInterface || !m_GoodbyeInterface)
        {
            throw std::runtime_error("Could not get all needed interfaces!");
        }
    }

    BEGIN_SDV_INTERFACE_MAP()
        SDV_INTERFACE_ENTRY(IShowExample)
    END_SDV_INTERFACE_MAP()

    DECLARE_OBJECT_CLASS_NAME("Access_Component")
    DECLARE_OBJECT_CLASS_TYPE(sdv::EObjectType::BasicService);
    
    /**
    * @brief Show messages, implements the function of IShowExample
    */
    void Show() override
    {
        m_HelloInterface->SayHello();
        m_GoodbyeInterface->SayGoodbye();
    }

private:
    ISayHello *   m_HelloInterface   = nullptr;
    ISayGoodbye * m_GoodbyeInterface = nullptr;
};

DEFINE_SDV_OBJECT(CAccessComponent)

With the GetInterface templated function one can get access to the interfaces of an IInterfaceAccessPtr object.

Check interface validity

#include <iostream>
#include <stdexcept>

#include "example_interfaces.h"

#include <support/component_impl.h>

class CAccessComponent
    : public sdv::CSdvObject
    , public IShowExample
{
public:
    CAccessComponent()
    {
        m_HelloInterface = sdv::core::GetObject("Hello_Component").GetInterface<ISayHello>();

        sdv::TInterfaceAccessPtr helloComp = sdv::core::GetObject("Hello_Component");
        m_GoodbyeInterface = helloComp.GetInterface<ISayGoodbye>();

        if (!m_HelloInterface || !m_GoodbyeInterface)
        {
            throw std::runtime_error("Could not get all needed interfaces!");
        }
    }

    BEGIN_SDV_INTERFACE_MAP()
        SDV_INTERFACE_ENTRY(IShowExample)
    END_SDV_INTERFACE_MAP()

    DECLARE_OBJECT_CLASS_NAME("Access_Component")
    DECLARE_OBJECT_CLASS_TYPE(sdv::EObjectType::BasicService);
    
    /**
    * @brief Show messages, implements the function of IShowExample
    */
    void Show() override
    {
        m_HelloInterface->SayHello();
        m_GoodbyeInterface->SayGoodbye();
    }

private:
    ISayHello *   m_HelloInterface   = nullptr;
    ISayGoodbye * m_GoodbyeInterface = nullptr;
};

DEFINE_SDV_OBJECT(CAccessComponent)

Since GetInterface returns nullptr if the given interface is not part of the object or if the object could not be found, it is recommended to check for nullptr s before continuing.

Use of an interface

#include <iostream>
#include <stdexcept>

#include "example_interfaces.h"

#include <support/component_impl.h>

class CAccessComponent
    : public sdv::CSdvObject
    , public IShowExample
{
public:
    CAccessComponent()
    {
        m_HelloInterface = sdv::core::GetObject("Hello_Component").GetInterface<ISayHello>();

        sdv::TInterfaceAccessPtr helloComp = sdv::core::GetObject("Hello_Component");
        m_GoodbyeInterface = helloComp.GetInterface<ISayGoodbye>();

        if (!m_HelloInterface || !m_GoodbyeInterface)
        {
            throw std::runtime_error("Could not get all needed interfaces!");
        }
    }

    BEGIN_SDV_INTERFACE_MAP()
        SDV_INTERFACE_ENTRY(IShowExample)
    END_SDV_INTERFACE_MAP()

    DECLARE_OBJECT_CLASS_NAME("Access_Component")
    DECLARE_OBJECT_CLASS_TYPE(sdv::EObjectType::BasicService);
    
    /**
    * @brief Show messages, implements the function of IShowExample
    */
    void Show() override
    {
        m_HelloInterface->SayHello();
        m_GoodbyeInterface->SayGoodbye();
    }

private:
    ISayHello *   m_HelloInterface   = nullptr;
    ISayGoodbye * m_GoodbyeInterface = nullptr;
};

DEFINE_SDV_OBJECT(CAccessComponent)

To use an interface one just calls the appropriate functions defined by it, since it is no more than a pointer to its type.

Note

For objects to be accessible they need to be declared in the Config File which has to be loaded by sdv::core:CVAPIControl::Initialize in a VAPI Core Process. See also the Example of a Config File.

Example access to other components#

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