TDoubleLinkedBufIndex

type TDoubleLinkedBufIndex = class(TBufIndex)

public

  FLastRecBuf: PBufRecLinkItem;

  FFirstRecBuf: PBufRecLinkItem;

  FNeedScroll: Boolean;

  function ScrollBackward; override;

Scrolls the index toward the beginning of the index.

  function ScrollForward; override;

Scrolls the index towards the end of the index.

  function GetCurrent; override;

  function ScrollFirst; override;

Scrolls to the first entry in the index.

  procedure ScrollLast; override;

Scrolls to the last entry in the index.

  function GetRecord(); override;

  procedure SetToFirstRecord; override;

  procedure SetToLastRecord; override;

  procedure StoreCurrentRecord; override;

  procedure RestoreCurrentRecord; override;

  function CanScrollForward; override;

Indicates if the index can be scrolled towards the end of the index.

  procedure DoScrollForward; override;

Implements actions needed to scroll forward using the index.

  procedure StoreCurrentRecIntoBookmark(); override;

  procedure StoreSpareRecIntoBookmark(); override;

  procedure GotoBookmark(); override;

Navigates the index to the specified Bookmark.

  function CompareBookmarks(); override;

  function SameBookmarks(); override;

Compares Bookmark values for ordering in the index.

  procedure InitialiseIndex; override;

Initializes the index.

  procedure InitialiseSpareRecord(); override;

Initializes the spare record in the index.

  procedure ReleaseSpareRecord; override;

Releases the spare record in the index.

  procedure BeginUpdate; override;

  procedure AddRecord; override;

Adds a record to the index.

  procedure InsertRecordBeforeCurrentRecord(); override;

Inserts a record prior to the current record in the index.

  procedure RemoveRecordFromIndex(); override;

Removes the record at the specified Bookmark from the index.

  procedure OrderCurrentRecord; override;

  procedure EndUpdate; override;

end;

TDoubleLinkedBufIndex

Implements an index using a doubly-linked list.

TBufIndex

Defines the interface used to implement indexes in TBufDataset.

TObject

TBufIndex

Defines the interface used to implement indexes in TBufDataset.

TBufRecLinkItem

Stores bookmarks to the previous and next records in a linked list.

PBufRecLinkItem

Pointer to a TBufRecLinkItem type.

TBufDataset

Implements a database-aware buffered dataset.