In Progress-4GL如何設置對象以接受不同數量的輸入？

Question

使用openedge 10.2.b ItemObj.cls

CLASS mystuff.ItemObj : 
    METHOD PUBLIC CHARACTER GetItemDesc 
    (INPUT pcOne AS CHARACTER, 
    INPUT pcTwo AS CHARACTER, 
    INPUT piThree AS INTEGER) : 

    RETURN pcOne pcTwo pcThree. 

END METHOD. 

ItemObj.p

USING mystuff.*. 
DEFINE VARIABLE rItemObj AS CLASS mystuff.ItemObj NO-UNDO. 
rItemObj = NEW mystuff.ItemObj(). 
MESSAGE "One : " rItemObj:GetItemDesc (1)  SKIP(1) 
     "Two : " rItemObj:GetItemDesc (1, 2) SKIP(1) 
     "Three : " rItemObj:GetItemDesc (1, 2, 3) VIEW-AS ALERT-BOX INFO. 
DELETE OBJECT rItemObj. 

我希望所有這些語句的輸出，使得如果用戶輸入只輸入1的是相同的另外兩個默認爲2和3，如果用戶輸入1和2相同，三是默認爲3

如何做到這一點沒有得到一個不匹配參數錯誤？

Answer 1

IIRC進展不允許在方法定義的可選參數，所以你必須創建每個參數置換的方法定義或接受處理多個值作爲像動態數組，臨時表的參數的數據結構或自定義對象並解壓縮（但是然後你將邏輯推到你的調用者上）。

CLASS mystuff.ItemObj: 
    METHOD PUBLIC CHARACTER GetItemDesc (INPUT pcOne AS CHARACTER, 
             INPUT pcTwo AS CHARACTER, 
             INPUT piThree AS INTEGER): 
    RETURN pcOne pcTwo pcThree. 
    END METHOD. 

    METHOD PUBLIC CHARACTER GetItemDesc (INPUT pcOne AS CHARACTER, 
             INPUT pcTwo AS CHARACTER): 
    RETURN GetItemDesc(pcOne, pcTwo, 3). 
    END METHOD. 

    METHOD PUBLIC CHARACTER GetItemDesc (INPUT pcOne AS CHARACTER): 
    RETURN GetItemDesc(pcOne, "2"). 
    END METHOD. 
END CLASS.