語法樹系統翻修過程中null指標的處理

Null Pointer Handling in Reimplementing a Syntax Tree System

花于雱(Yu-Pang Hua)

指導教授 ： 廖賀田

淡江大學/商管學院/資訊管理學系碩士班/碩士(2015年)

https://doi.org/10.6846/TKU.2015.01082

摘要

為支援軟體混亂器[2]，我們以先前Java直譯器[1]中的語法樹系統為雛型，做進一步的重整及開發。新版的語法樹類別包含有關聯欄位，形成雙向鏈結的關係，它們必須即時性地確保雙向關係的一致性。
null在程式語言中是不可或缺的一環，但它卻使除錯變得困難。當規模龐大的程式發生null指標例外時，很難立即追蹤到造成錯誤的所在。
為了解決這問題，本論文提出一套對null指標的處理方式。依程式的使用狀況，以illegal type或none type取代原本使用null的地方。減少除錯的成本並使專案得以在更穩定的環境下開發。

關鍵字

Java ； null pointer ； 語法樹

並列摘要

To support software obfuscator [2], we applied the syntax tree system as the model for further development and refactory system we had developed in the Java interpreter [1]. The new version of syntax tree system’s class contains relation fields with two-way link between these. A relation field must ensure that those relationships are consistent in real time.
Null is extensively used in programming languages. However, it makes debug becomes difficult. When the large-scale programs exploded the null pointer exception, it is rather difficult to immediately know how that occurred.
To solve this problem, in this paper, we propose a methodology on null pointer handling. According to code’s statue, illegal type or none type is used to replace the original use of null's place. The cost of debugging and the program to be developed in the stability environment was reduced.

並列關鍵字

Java ； null pointer ； Syntax Tree

參考文獻

[1] 周敬斐, 郭肇安, 廖賀田*，〈Java的語法樹直譯器 (A Syntax-Tree-Based Interpreter for Java) 〉，資訊管理展望，第10卷，第1期，頁 111-135, Jun. 2008.

[2] Heh-Tyan Liaw, and Shih-Chieh Wei, “Obfuscation for object-oriented programs: dismantling instance methods”, Software-Practice and Experience, Apr. 2013.

[4] The Nice programming language, http://nice.sourceforge.net/, 2006.

[8]Martin Fowler, “Refactoring - Improving the Design of Existing Code”, Addison-Wesley, 2003.

[10] Grady Booch, “Object-Oriented Analysis and Design with Applications , third edition”, Addison-Wesley 2007.