Remedy ARS 7.6.03 overlay

一個Remedy産品史上較大的新功能正在被大多數人忽視和繞過，實在是不吐不快，也希望所有的Remedy開發人員能夠關注一下這個功能，因為他可能真的對你的項目非常重要。

上圖顯示了Overloay對象的地位和功用，我們都是工作在BMC原廠的開箱即用的程式對象層面上，所有安裝程式首次安裝到系統上的應用的所有對象都是Base對象。在這個基礎之上我們做定制和開發，定制和開發出來的對象有兩種，一種是Overlay對象，中文翻譯為疊加對象，這種疊加對象并不會對原有的Base對象進行修改，而是覆寫在其之上的，兩者是和諧共存的。另外一種對象就是純客戶化的對象，即以前沒有，開發人員新加入的對象，這種對象和其他兩種對象是沒有沖突的。

Overlay可以是Base對象保持原狀有什麼意義？最重要的一點就是對更新有好處，以前我們開發的所有Remedy應用系統，大家都不敢做更新，當客戶或者BMC的support要求要更新的時候，我們都會抵制或反對，這裡的原因相信大家心裡都知道。那麼以後大家就不必這樣了，隻要在開發定制的過程中合理的使用Overlay對象做定制開發，方能保證定制後的系統對更新檔和更新來者不拒。

那麼如何使用到Overlay對象呢？在Dev Studio中選中需要修改的對象，點右鍵選擇create overlay，你就能在原廠的對象上做一個疊加對象了。這裡提出一個7.6.04 Dev Studio的錯誤做法：預設登入到Dev Studio以後，你可能會發現在預設的最佳實踐模式下，你不能向以前一樣任意修改東西，發現在切換到另外一個模式（好像是經典模式）之後又什麼都能修改了，是以你就認為找到了修改的方法，其實這種操作恰恰是繞過了Overlay功能。在這種模式等于在以前舊版本産品的模式下開發做。

老外如是說：What the overlay feature does is to simply allow you to do the following:

1) Add new items that are identified as custom items you have added.  They are flagged as custom items in the displays.  You can easily sort by and get a list of custom items.  And it is COMPLETE.  You don’t have to worry if you are missing one or if you forgot about something you added.

2) Update existing items by leaving the original definition there and updating a copy of that definition with your changes.

a) all the benefits of #1 are present AND your changes have the exact same name/identification as the original

b) you can at any time see your version vs. the original to see exactly what has changed from out of the box

c) Not have to deal with “ripple changes”.  By this I mean that if in the past you copied a filter to a new name (to avoid overwrite at upgrade), you had to copy any guide that included it and then any workflow that called the guide to use the new name.   The fact that the items are the SAME ITEM means that there is no need to change other things.

d) When an upgrade occurs, the definitions in the base layer are changed but NOTHING about the items you have overlaid (or added custom) are changed. So, your changes are not overwritten.  In fact, your changes continue to be the overlay and continue to sit on top of and override the definition that was newly imported with the same name/id.

e) After the upgrade, you can again compare your overlay with the new out of the box definition to see if there is anything that should change.  Maybe the out of the box does the right thing now and you should remove your overlay or maybe there is an extended set of actions and you need to pick up one or more of the new actions in your overlay.

The key is that it provides an automatic and inherent layer that is YOUR layer that sits over the out of the box definition and allows you to safely, clearly, and cleanly adjust or augment the defintions if needed for your environment.

This is a feature that allows you to gain further and tighter control over your environment.  It is something that provides you with the ability to better understand what is stock and what is custom and what is changed about the solution.  It is one that preserves all changes you have made across upgrades with a layer of independence and yet links so that changes stay tied into the solution without the change you have made being updated by the upgrade itself.

突然想講這樣的一個故事，如果曾經發生在你身上，就當是個笑話吧。Remedy ITSM套件就好比是一個精裝别墅，BMC一般會告訴客戶，那裡面有世界上最豪華的設施和裝修，直接拿着行李入住就行了，事實如此！不過客戶往往沒有先看進屋看個究竟（其實往往使用者沒有這個機會，因素複雜，我不說你懂得），就找來施工隊，提出我是有這樣那樣生活習慣和品位的，這都是對此房子的期望和需求，我的上帝客戶啊！東西你都買了為啥就不先試住一下呢？嘗試新鮮事物的精神您有木有？接着施工隊的勞工（也就是我們的Remedy程式開發人員）被工頭（項目經理）帶着就進屋了，說我們就是專業幹這個的，能保證按時上線，您就等好吧！客戶在院子裡站着，瞧着施工隊拿着需求分析書和開發工具進進出出，在屋裡叮叮當當緊着忙活，幾個月之後，項目經理過來說，我們可以做上線教育訓練了（或者試運作/或者UAT測試了），這下客戶才真的走進屋，客戶開始納悶了，心裡直嘀咕，這真的是别墅麼？好像有點糙啊！項目經理說，我們正式按照您的訓示，已經把它做成中式風格了，老美的東西怕您用不慣。就這樣客戶茫然的也就入住了，其實客戶可能隻也住在了别墅某一層的一間屋裡。通往其它房間的門都被封了，并且貼上了桌面，或者被新打的大衣櫃給擋住了，每次回家都是從窗台爬梯子上去。

對任何項目而言，在原廠産品上的定制開發是必須的，但是往往是項目的無底洞，那麼如何規避這種風險？怎樣讓Remedy ITSM産品開箱即用的功能發揮到最大化？無疑對産品已有能力的挖潛和利用也要花時間精力成本去研究，這個時間和開發定制的工作時間是沖突沖突的。那麼：讓客戶先試住，在逐漸裝修，可能才是平衡沖突的關鍵。客戶也應該把項目實施和開發的資金做一個規劃，切勿在前期投入太大，項目的前期，應該是學習産品和适應最佳實踐的過程。實施方應該想方設法的讓客戶先進屋看清楚，和客戶一起住一段時間，之後在去開工裝修，這個過程應該是項目美好的蜜月期。