Object-oriented Software in Ada 95

286 Persistence
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When added to a binary tree, this would recreate the tree structure present in the original object.
procedure Finalize( The:in out Pic ) is
Per : Io.File_Type; --File descriptor
procedure Rec_Finalize( The:in Subtree ) is --Save state
begin
if The /= null then --Subtree save as
Io.Write( Per, The.Rec ); -- Item
Rec_Finalize( The.Left ); -- LHS
Rec_Finalize( The.Right ); -- RHS
end if;
end Rec_Finalize;
begin
if To_String(The.Obj_Id) /= "" then --If save state
Io.Create( Per, Io.Out_File,
To_String( The.Obj_Id ) );
Rec_Finalize( The.Tree );
Io.Close( Per );
end if;
Release_Storage( The.Tree );
exception
--Return real exception
when others => raise Per_Error; -- as sub code
end Finalize;
The procedure Discard disassociates the object identity from the object and resets the state of the tree to
empty. This procedure should be used when the object’s state is not required to be saved to disk.
procedure Discard egin
Set_Name( The, "" );
Release_Storage( The.Tree );
end Discard;
--No name
--Release storage
procedure Set_Name( The:in out Pic; Id:in String ) is
begin
The.Obj_Id := To_Unbounded_String(Id); --Set object name
end Set_Name;
function Get_Name( The:in Pic ) return String is
begin
return To_String( The.Obj_Id ); --Name of object
end Get_Name;
© M A Smith - May not be reproduced without permission