Overview

A pipeline component is a Component Object Model (COM) server object that implements the IPipelineComponent interface. The following is the definition of this interface that appears in pipecomp.idl:

    interface IPipelineComponent : IUnknown
    {
        import "oaidl.idl";

        HRESULT Execute(
                    [in]            IDispatch*  pdispOrder,
                    [in]            IDispatch*  pdispContext,
                    [in]            LONG        lFlags,
                    [out,retval]    LONG*       plErrorLevel
                );

        //
        // By default, a pipeline is in "execution mode", this call is         // used to prepare the pipeline for "design mode" (fEnable ==             //  TRUE) or to go to design mode (fEnable = FALSE).
        //

        HRESULT EnableDesign( [in]    BOOL fEnable );

    };

When the pipeline creates an instance of a component, it requests an interface pointer on the component's IPipelineComponent implementation, then uses this pointer to invoke IPipelineComponent::Execute.

The IPipelineComponent is the only interface that a component must implement to function within the pipeline. However, to enhance a component's usability, or to take advantage of the transaction capabilities of Microsoft Transaction Server, you may also design your component to implement one or more of the following interfaces:

• IDispatch. Implementing is optional. It makes it possible for clients to access your component's capabilities from macro languages, such as Microsoft® Visual Basic Scripting Edition (VBScript), Microsoft® JavaScript™ (JScript), or Microsoft® Visual Basic®.
• IPipelineComponentAdmin. Inherits from IDispatch, and makes it possible for you to extend your component's capabilities without modifying the interface that implements those capabilities. This interface defines the GetConfigData and SetConfigData methods, to which the caller passes a Dictionary. GetConfigData and SetConfigData write or read this Dictionary to retrieve or set configuration data on the component.
• IPipelineComponentDescription. Implementing is optional, but for usability purposes, is highly recommended. When you implement IPipelineComponentDescription, you identify to the Pipeline Editor the OrderForm name/value pairs that your component reads and writes, as well as the pipe context objects that your component uses. When the user double-clicks the node for your component in the Pipeline Editor, the Pipeline Editor displays these name/value pairs in a tab, provided that the component implements IPipelineComponentDescription.
• IPersistStreamInit. Makes it possible for the properties on your component to be saved and loaded to and from persistent storage through the Pipeline Editor.
• IPersistXML. Makes it possible for your component's data to be loaded and saved as an XML stream.

Note  If you are designing an object to be used by the Mapping components included in the Commerce Interchange Pipeline (CIP), the component must implement either IPersistStreamInit or IPersistXML.