FDO RFC 9 - Add new class FdoLiteralValueCollection and new method to FdoLiteralValue

This page contains a request for comments document (RFC) for the FDO Open Source project. More FDO RFCs can be found on the RFCs page.

Status

RFC Template Version	(1.0)
Submission Date	Aug 10, 2007
Last Modified	Jack Lee Timestamp
Author	Jack Lee
RFC Status	Draft
Implementation Status	Under Development
Proposed Milestone	3.3.0.0
Assigned PSC guide(s)	Greg Boone
Voting History	TBD
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Overview

The purpose of this RFC is

• add the GetLiteralValueType method to FdoLiteralvalue class

• add the FdoLiteralValueCollection class

Motivation

1) Currently, a FdoDataValue or FdoGeometryValue can be derived from FdoLiteralValue.

The only way to determine the type of object is to use a dynamic cast:

if (dynamic_cast<FdoDataValue*>(literalValue) != NULL)
{
    // DataValue
    ...
}
else if (dynamic_cast<FdoGeometryValue*>(literalValue) != NULL)
{
    // GeometryValue
    ...
}

2) The FdoLiteralValue class exists but the collection of FdoLiteralValue objects does not exist.

Proposed Solution

1) Add GetLiteralValueType method to FdoLiteralValue class

This methods returns the literal type(data or geometry).

For the unmanaged code:

enum FdoLiteralValueType
{
    FdoLiteralValueType_Data,

    FdoLiteralValueType_Geometry,

};

class FdoLiteralValue : public FdoValueExpression
{
public:
      FDO_API virtual FdoLiteralValueType GetLiteralValueType() = 0;
};

The following

if (dynamic_cast<FdoDataValue*>(literalValue) != NULL)
{
    // DataValue
    ...
}
else if (dynamic_cast<FdoGeometryValue*>(literalValue) != NULL)
{
    // GeometryValue
    ...
}

can be changed to :

if (literalValue->GetLiteralValueType() == FdoLiteralValueType_Data)
{
   // DataValue
   ...
}
else if (literalValue->GetLiteralValueType() == FdoLiteralValueType_Geometry)
{
   // GeometryValue
   ...
}

For the managed code:

public __value enum LiteralValueType
{
      LiteralValueType_Data = FdoLiteralValueType_Data,

      LiteralValueType_Geometry = FdoLiteralValueType_Geometry

};

public __gc class LiteralValue : public NAMESPACE_OSGEO_FDO_EXPRESSION::ValueExpression
{
public:
    __property NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValueType get_LiteralValueType();

public private:
      inline FdoLiteralValue* GetImpObj();
};

2) Add the FdoLiteralValueCollection class

For the unmanaged code:

class FdoLiteralValueCollection : public FdoCollection<FdoLiteralValue, FdoExpressionException>
{
protected:
    FdoLiteralValueCollection() : FdoCollection<FdoLiteralValue, FdoExpressionException>()
    {
    }

    virtual ~FdoLiteralValueCollection()
    {
    }

    virtual void Dispose()
    {
        delete this;
    }

public:
    /// \brief
    /// Constructs a default instance of an FdoLiteralValueCollection.
    /// 
    /// \return
    /// Returns FdoDataValueCollection
    /// 
    FDO_API static FdoLiteralValueCollection* Create();
};

For the managed code:

public __sealed __gc class LiteralValueCollection : public NAMESPACE_OSGEO_RUNTIME::Disposable, public System::Collections::IList
{
/// \cond DOXYGEN-IGNORE
public private:
      inline FdoLiteralValueCollection* GetImpObj();

public:
    /// \brief
    /// The defaut constructor for the object
    /// 
      LiteralValueCollection();

    /// \brief
    /// Constructs a LiteralValueCollection object based on an unmanaged instance of the object
    /// 
    /// \param unmanaged 
    /// Input A Pointer to the unmanaged object.
    /// 
    /// \param autoDelete 
    /// Input Indicates if the constructed object should be automatically deleted 
    /// once it no longer referenced.
    /// 
      LiteralValueCollection(System::IntPtr unmanaged, System::Boolean autoDelete);

    /// \brief
    /// Gets the count of items in collection.
    /// 
    /// \return
    /// Returns the number of items in the collection.
    /// 
      __property System::Int32 get_Count(System::Void);

    /// \brief
    /// Gets an enumerator that can iterate through a collection.
    /// 
    /// \return
    /// Returns an enumerator on the dictionary.
    /// 
      __sealed System::Collections::IEnumerator* GetEnumerator(System::Void);

    /// \brief
    /// Removes the index-th ArgumentDefinition from this collection.
    /// 
    /// \param index 
    /// Input index of the element to remove.
    /// 
      System::Void RemoveAt(System::Int32 index);

    /// \brief
    /// Removes all elements from the collection.
    /// 
      System::Void  Clear();

    /// \brief
    /// Adds a ArgumentDefinition object into the collection.
    /// 
    /// \param value 
    /// Input the ArgumentDefinition object to add.
    /// 
    /// \return
    /// Returns the position into which the new element was inserted.
    /// 
      System::Int32 Add(LiteralValue* value);

    /// \brief
    /// Determines the index of a specific ArgumentDefinition object.
    /// 
    /// \param value 
    /// Input the ArgumentDefinition object to locate in the collection.
    /// 
    /// \return
    /// The index of value if found in the collection; otherwise, -1.
    /// 
      System::Int32 IndexOf(NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValue* value);

    /// \brief
    /// Inserts a ArgumentDefinition object into the collection at the specified position.
    /// 
    /// \param index 
    /// Input the zero-based index at which value should be inserted.
    /// \param value 
    /// Input the ArgumentDefinition object to insert.
    /// 
      System::Void Insert(System::Int32 index, NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValue* value);

    /// \brief
    /// Removes the first occurrence of a specific ArgumentDefinition object.
    /// 
    /// \param value 
    /// Input the ArgumentDefinition object to remove from the collection.
    /// 
      System::Void Remove(NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValue* value);

    /// \brief
    /// Determines whether the collection contains a specific ArgumentDefinition object.
    /// 
    /// \param value 
    /// Input The ArgumentDefinition object to search in the collection.
    /// 
    /// \return
    /// Returns true if the value is found in the collection; otherwise, false.
    /// 
      System::Boolean Contains(NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValue* value);

    /// \brief
    /// Copies the elements of the collection to an array.
    /// 
    /// \param array 
    /// Output the one-dimensional Array that is the destination of the elements copied from this collection.
    ///
    /// \param startAt 
    /// Input an integer that represents the index in array at which copying begins.
    /// 
      System::Void CopyTo(NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValue* array[],System::Int32 startAt);

    /// \brief
    /// Gets the item in the collection at the specified index. 
    /// 
    /// \param index 
    /// The index of the item in the collection. The index is 0 based.
    /// 
    /// \return
    /// Returns an instance of a the collected item.
    /// Throws an instance of Exception if the index is out of range or an error occurs.
    /// 
      __property NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValue* get_RealTypeItem(System::Int32 index);

    /// \brief
    /// Sets the value of the item at the specified index
    /// 
    /// \param index 
    /// Input index of the item to set.
    /// 
    /// \param value 
    /// Input the value of the item
    /// 
      __property System::Void  set_RealTypeItem(System::Int32 index, NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValue* value);

    /// \brief
    /// Gets an item in the collection.
    /// 
    /// \param index 
    /// Input index of the item to retrieve.
    /// 
    /// \return
    /// Returns the item at the specified index
    /// 
      __property NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValue* get_Item(System::Int32 index);

    /// \brief
    /// Sets the value of the item at the specified index
    /// 
    /// \param index 
    /// Input index of the item to set.
    /// 
    /// \param value 
    /// Input the value of the item
    /// 
      __property System::Void  set_Item(System::Int32 index, NAMESPACE_OSGEO_FDO_EXPRESSION::LiteralValue* value);

/// \cond DOXYGEN-IGNORE
/// \endcond
};

Implications

This change will not cause any functional or performance side effects.

Test Plan

Existing unit tests will be expanded to test the proposed enhancements defined above.

Funding/Resources

Autodesk to provide resources / funding to update the FDO API.