//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2011 Greenplum, Inc.
//
//	@filename:
//		IMDCacheObject.h
//
//	@doc:
//		Base interface for metadata cache objects
//---------------------------------------------------------------------------



#ifndef GPMD_IMDCacheObject_H
#define GPMD_IMDCacheObject_H

#include "gpos/base.h"

#include "naucrates/md/CMDName.h"
#include "naucrates/md/IMDId.h"
#include "naucrates/md/IMDInterface.h"


// fwd decl
namespace gpos
{
class CWStringDynamic;
}
namespace gpdxl
{
class CXMLSerializer;
}

namespace gpmd
{
using namespace gpos;

//---------------------------------------------------------------------------
//	@class:
//		IMDCacheObject
//
//	@doc:
//		Base interface for metadata cache objects
//
//---------------------------------------------------------------------------
class IMDCacheObject : public IMDInterface
{
public:
	// Serialize a list of metadata id elements using pstrTokenList
	// as the root XML element for the list, and each metadata id is
	// serialized in the form of a pstrTokenListItem element.
	// The serialized information looks like this:
	// <strTokenList>
	//		<strTokenListItem .../>...
	// </strTokenList>
	static void SerializeMDIdList(CXMLSerializer *xml_serializer,
								  const IMdIdArray *mdid_array,
								  const CWStringConst *strTokenList,
								  const CWStringConst *strTokenListItem);

	// type of md object
	enum Emdtype
	{
		EmdtRel,
		EmdtInd,
		EmdtFunc,
		EmdtAgg,
		EmdtOp,
		EmdtType,
		EmdtCheckConstraint,
		EmdtRelStats,
		EmdtColStats,
		EmdtCastFunc,
		EmdtScCmp,
		EmdtExtStats,
		EmdtExtStatsInfo,
		EmdtSentinel
	};

	// md id of cache object
	virtual IMDId *MDId() const = 0;

	// cache object name
	virtual CMDName Mdname() const = 0;

	// object type
	virtual Emdtype MDType() const = 0;

	// serialize object in DXL format
	virtual void Serialize(gpdxl::CXMLSerializer *) const = 0;

	// DXL string representation of cache object
	virtual const CWStringDynamic *GetStrRepr() = 0;


	// serialize the metadata id information as the attributes of an
	// element with the given name
	virtual void SerializeMDIdAsElem(gpdxl::CXMLSerializer *xml_serializer,
									 const CWStringConst *element_name,
									 const IMDId *mdid) const;

#ifdef GPOS_DEBUG
	virtual void DebugPrint(IOstream &os) const = 0;
#endif
};

using IMDCacheObjectArray = CDynamicPtrArray<IMDCacheObject, CleanupRelease>;

}  // namespace gpmd



#endif	// !GPMD_IMDCacheObject_H

// EOF