Modifiability Back

• Modifiability(可修改性)注重的是一個系統修改所需的代價
• 軟件幾乎不可能不發生改變, 因為一個軟件其與外部的關係是無限的, 外界一個因素的影響都將引起系統的改變.
• 提高軟件可修改性涉及到設計模式 (Design Pattern).
• 儘量達到高內聚, 低耦合, 降低依賴
  • 語法上的依賴(接口, 方法等)
  • 語義上的依賴(數據的語義不同)

Scenarios(場景)

• example:

Tatics(策略)

1. Localize Change

• Semantic Coherence: 維持語義的一致性
• Anticipate Expected Changes: 預測預期的修改
• Generalize Module: 通用化模塊
• Limit Possible Options: 限制可能的選項
• Abstract Common Service: 抽象出公共的服務

2. Prevention of Ripple Effect(漣漪效應)

• Hide information: 把類中的屬性儘量設置成private或protected.
• Maintain Existing interface: 維持現有的接口, 而不去改變它.
• Restrict Communication Path: Facade模式, 提供統一的門戶.

3. Defer Binding Time(延遲綁定時間)

• Runtime Registration
• Publish/Subscribe
• Configuration files: 通過配置文件避免數據寫入代碼
• Polymorphism: 動態綁定, 只有運行時才知道具體的實現
• Component Replacement: 用現成的框架去替換
• Adherence to defined protocols: 堅守已經定義的協議來修改

Comments Copyright © aleen42 all right reserved, powered by aleen42

Empty Comments

Sign in GitHub

As the plugin is integrated with a code management system like GitLab or GitHub, you may have to auth with your account before leaving comments around this article.

Notice: This plugin has used Cookie to store your token with an expiration.

authorize