遞歸在算法在工作流程引擎中的應用

遞歸做為一種算法在程序設計語言中廣泛應用.是指函數/過程/子程序在運行過程中直接或間接調用自身而產生的重入現象.遞歸是計算機科學的一個重要概念,遞歸的方法是程序設計中有效的方法,采用遞歸編寫程序能使程序變得簡潔和清晰.。

遞歸在工作流程引擎中有廣泛的應用，以以下事例來說明：

應用一：退回到指定的節點，要把當前節電與退回節點之間的節點數據清空。

/// <summary>         /// 遞ÌY歸¨¦刪¦?除y兩¢?個?節¨²點Ì?之?間?的Ì?數ºy據Y         /// </summary>         /// <param name="nds">到Ì?達ä?的Ì?節¨²點Ì?集¡¥合?</param>         publicvoid DeleteToNodesData(Nodes nds)         {             /*開a始º?遍À¨¦歷¤¨²到Ì?達ä?的Ì?節¨²點Ì?集¡¥合?*/             foreach (Node nd in nds)             {                 Work wk = nd.HisWork;                 wk.OID = this.WorkID;                 if (wk.Delete() == 0)                 {                     wk.FID = this.WorkID;                     if (wk.Delete(WorkAttr.FID, this.WorkID) == 0)                         continue;                 }                   /*說¦Ì明¡Â:已°?經-刪¦?除y該?節¨²點Ì?數ºy據Y。¡ê*/                 DBAccess.RunSQL("DELETE WF_GenerWorkerList WHERE (WorkID=" + this.WorkID + " OR FID=" + this.WorkID + ") AND FK_Node=" + nd.NodeID);                   //刪¦?除y正y常¡ê的Ì?垃¤?圾?數ºy據Y。¡ê                 DBAccess.RunSQL("DELETE WF_GenerWorkFlow WHERE WorkID NOT IN (SELECT WorkID FROM WF_GenerWorkerList )");                 DBAccess.RunSQL("DELETE WF_GenerFH WHERE FID NOT IN (SELECT FID FROM WF_GenerWorkerList)");                                    DeleteToNodesData(nd.HisToNodes);             }         }

應用二：在分合流程過程中，流程結束時，要根據用戶的需要判斷并殺掉沒有完成的進程。

/// <summary>         /// 結¨¢束º?流¢¡Â程¨¬         /// </summary>         /// <returns></returns>         publicstring DoFlowOver()         {             // 建¡§立¢¡é流¢¡Â程¨¬事º?例¤y。¡ê             GenerWorkFlow gwf = newGenerWorkFlow(this.WorkID);             Node nd = newNode(gwf.FK_Node);             string msg = this.BeforeFlowOver();               //先¨¨讓¨?它¨¹的Ì?子Á¨®流¢¡Â程¨¬結¨¢束º?。¡ê             WorkerLists wls = newWorkerLists();             wls.Retrieve(WorkerListAttr.FID, this.WorkID);             foreach (WorkerList wl in wls)             {                 WorkFlow wf = newWorkFlow(wl.FK_Flow, wl.WorkID);                 wf.DoFlowOver();             }     。。。。。。。。。。。。。。    ｝

應用三:根據當前節點的ID,向上追溯一個分流節點。

/// <summary>         /// 獲?取¨?它¨¹的Ì?上¦?一°?步?的Ì?分¤?流¢¡Â點Ì?         /// </summary>         privateNode _GetHisPriFLNode(Nodes nds)         {             foreach (Node mynd in nds)             {                 if (mynd.IsHL)                     return mynd;                 else                     return _GetHisPriFLNode(mynd.HisFromNodes);             }             returnnull;         }         /// <summary>         /// 它¨¹的Ì?上¦?一°?步?分¤?流¢¡Â節¨²點Ì?         /// </summary>         publicNode HisPriFLNode         {             get             {                 return _GetHisPriFLNode(this.HisFromNodes);             }         }