Example of Custom Data Extraction Algorithm

The section describes the custom algorithm of data extraction implemented as the MyDtCustomProvider class in the Fore language.

Data is loaded from the C:\Data_Out.txt text file .

Add links to the Dt, Xml system assemblies.

Public Class MyDtCustomProvider: Object, IDtCustomProvider
    _mb: IMetabase;
    p: IDtTextProvider;
    fs: IDtFieldDefinitions;
    m_active, keep: Boolean;

    Public Constructor MyDtCustomProvider;
    Begin
        m_Active := False;
    End Constructor MyDtCustomProvider;

    Public Sub Open;
    Begin
        m_Active := True;
        If p = Null Then
            p := New DtTextProvider.Create;
            p.File := "C:\Data_Out.txt";
        End If;
        p.RangeHasHeader := True;
        p.Open;
    End Sub Open;

    Public Sub Close;
    Begin
        m_Active := False;
        p.Close;
    End Sub Close;

    Public Sub Save(Element: IXMLDOMElement);
    Begin
        p.Save(Element);
    End Sub Save;

    Public Sub Load(Element: IXMLDOMElement);
    Begin
        If p = Null Then
            p := New DtTextProvider.Create;
            p.File := "C:\Data_Out.txt";
        End If;
    End Sub Load;

    Public Sub FieldsFromFile;
    Begin
        p.FieldsFromFile;
    End Sub FieldsFromFile;

    Public Property GetType: DtObjectType
        Get
        Begin
            Return DtObjectType.TDtTextProvider;
        End Get
    End Property GetType;

    Public Sub ClearFields;
    Begin
        p.ClearFields;
    End Sub ClearFields;

    Public Sub Fetch(Var Values: Array);
    Begin
        p.Fetch(Values);
    End Sub Fetch;

    Public Function FetchRows(Count: Integer; Var Values: Array): Integer;
    Var
        i: Integer;
    Begin
        i := p.FetchRows(Count, Values);
        Return i;
    End Function FetchRows;

    Public Function ReadingRowsCount: Integer;
    Begin
        Return p.ReadingRowsCount;
    End Function ReadingRowsCount;

    Public Function ImplementFetchRows: Boolean;
    Begin
        Return True;
    End Function ImplementFetchRows;

    Function get_Eof: Boolean;
    Begin
        Return p.Eof;
    End Function get_Eof;

    Function get_Fields: IDtFieldDefinitions;
    Begin
        If fs = Null Then
            fs := p.Fields;
        End If;
        Return fs;
    End Function get_Fields;

    Function get_Active: boolean;
    Begin
        Return m_Active;
    End Function get_Active;

    Function get_getType: dtobjecttype;
    Begin
        Return dtobjecttype.TDtUserProviderEx
    End Function get_getType;

    Public Function get_Metabase: IMetabase;
    Begin
        Return _mb;
    End Function get_Metabase;

    Public Sub set_Metabase(metabase: IMetabase);
    Begin
        _mb := metabase;
    End Sub set_Metabase;

    Function get_KeepCalcFields: Boolean;
    Begin
        Return keep;
    End Function get_KeepCalcFields;

    Sub set_KeepCalcFields(Value: Boolean);
    Begin
        keep := Value;
    End Sub set_KeepCalcFields;
End Class MyDtCustomProvider;