JOSSO 1.7 Released - Confluence

JOSSO 1.7 Released - Confluence

Well, with the 1.7 release JOSSO has finally nullified my effort of maintaining a separate project providing a WebLogic-JOSSO adaptor. From today on, people should use JOSSO directly to achieve single-sign-on!

Lina Xu's Blog: WebLogic Operations Control (WLOC) Introduction

Lina Xu's Blog: WebLogic Operations Control (WLOC) Introduction

So BEA has indeed plans for virtualization market!

Virtualization products are important enabling technology for Corporate IT to turn their existing investment a step closer to in-house cloud computing. Hopefully this product will carry on even after the merger.

The right direction where JavaEE application server should be heading

With commoditization of JavaEE application server market, it's good to see application server vendor finding the right niche.

Finextra: LiquidityHub achieves eight millisecond latency for fixed-income price distributione

WebLogic Realtime and WebLogic Event Server are both designed to meet specific latency problems. Low-latency is an area that was forbidden for Java based applications because of uncontrollable pause time brought by garbage collection, a Java Virtual Machine feature that automatically frees up physical memory and re-allocates it.

So, for first time, low-latency applications can be achieved using Java, a common skill set, and Intel-based Hardware. If BEA executes this strategy well, it can find ways to commoditize upper industry sector that was predominantly an IBM territory. If that's the case, then BEA is definitely worth more than 21 dollars per share.

This also reminds me of a myth: how can some Wall Street analysts decide the value of a certain technology company if they don't know technology well? How such market consensus if reached?


Technorati Tags: bea, weblogic

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An in-depth article regarding IMS charging architecture

Definitely worth your time.

Understanding the IMS Charging Architecture

In addition to explaining the value of WebLogic SIP Server in telecom environment, this article provided an optimal point of entry for those interested in telecom charging architecture.

Telecommunication industry has always been a special niche for BEA. It's good to see BEA leveraging this well.

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Enterprise computing enters the 2nd phase of atom composition

It seems that everyone talks about being liquid, fluid as an entering ticket for virtualization market.

Red Hat has massive Linux fluidity moment | The Register

It is natural for Linux vendor to stand by virtualization. Although classical Redhat talk about the subject is always related to Xen, I think Redhat has finally done something beyond hype this time. To be fair, though, I must say that this is more a victory of Amazon instead of Redhat. After all, Amazon EC2 has been running close relative of Redhat Enterprise all the time, the partnership from Redhat has only endorsement value.

This media coverage, however, has given me a thought about virtualization selling model. As I have commented here, using software license model to sell virtualization products can pose a serious challenge for vendor like VMWare. Selling virtualization as on-demand service is, however, a completely different story.

Usually, small to medium enterprise are not typical target customer of IT consulting company, but those enterprise can benefit from virtualization nevertheless. While Fortune 500 companies are still not likely to adopt Amazon EC2 services, small to medium enterprise have less resistance on this front and are more likely to deploy their application on EC2. In this way, Amazon has opened new business opportunity without facing the political challenges of traditional IT warlords. How clever.

It would also be very interesting to see BEA WebLogic Server Virtual Edition run on EC2. For those of you who don't know about this BEA product, it is a special WebLogic Server edition that lets JRockit VM to act directly as underling guest OS in VMWare, saving computing overhead of OS level facilities. Currently this product is only certified against VMWare, but technically it shouldn't be too difficult to port it to run under EC2 architecture. What's more difficult is for BEA to decide whether it needs to tap into this changing market and change its license model from per CPU to per usage to appropriately map with this virtualization trend.

Technorati Tags: linux, bea, weblogic

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專案控管：JavaEE還是Spring Framework?

這個題目其實我已經想了很久，不過最近看到的一個Case又讓我覺得不能不寫一下這方面的想法。一個完整的軟體專案必須考慮到的因素當然很多，除去掉PMP那些必然會提到的因素之外，我個人認為專案經理仍然必須將一些開發前、中、後的因素加以仔細的考量，並且以宏觀的技術角度來思考整個專案成敗的問題。

不管是PMP或者CMMI都相當強調風險的控管，殊不知風險的預估可不像是人壽保險那樣有客觀的統計數據作為依據。如果無法掌握手中的技術，風險這種無形的東西並不是能夠委外的。實際上要思考的方向應該是，如何動用手上所有的技術和工具來讓軟體專案的風險能夠降低。

以我的標題作為例子，目前Spring Framework是門顯學。我應該是在台灣使用Spring Framework的先驅吧！我當然可以理解這樣技術的便利性。不過便利性不代表不需要了解底層內容。以Connection Pool為例，目前Developer都有使用Apache DBCP的概念；不過許多Developer所忘記的是，Connection Pool仍然是一種基於TCP/IP Socket的一種技術。Socket並不是可靠的、永久存在的，所以完整的Connection Pool實作往往都會搭配一些測試參數以確保Connection要用的時候仍然是可用的。舉例來說，BEA WebLogic Server的Connection Pool能設定每一段時間就對資料庫進行測試查詢，讓資料庫的連線不至於因為idle而被防火牆移除。就以Apache DBCP來講，這樣的參數也是存在的。重點是，了解這些底層的細節其實是開發人員應該要能夠Handle的事情；而專案經理必須知道這種問題會發生。Code並不是只要Work就好；系統是必須經過時間的考驗的。既然已經使用了WebLogic，那開發的角度應該是要將Application Server的特性考慮進去；不然應該就要有把握能夠使用Framework之後不會有問題。

事實上，Springframework其中一個大好處就是它的ApplicationContext.xml。只要設定更改了，Code完全不動的情況下，就可以將DBCP Connction Pool改成WebLogic的Connection Pool。透過這樣的做法，Unit test的時候還是可以使用個人的資料庫在不啟動Application Server的狀況下進行資料查詢邏輯的測試，然後在上線測試的時候再改成WebLogic的Connection Pool。Springframework的一個宗旨就是要讓開發能夠Scale up and down easily。使用它而沒有參透它的精神那就太可惜了。要記住，Springframework只是拿來掩蓋掉JavaEE的複雜度；身為一個負責任的開發人員或者專案經理，你還是必須對底層的技術有所了解。你所不了解的，就會是你的風險；這是無庸置疑的。

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WebLogic Server 9.2: 在Admin Console自訂Role Mapping

如果你管理一個跑在WebLogic Server上面的Web Application，你可以透過WebLogic Server內建的功能來管理User/Group以及Role之間的對應。如果不是透過這種方法，標準的做法就是透過web.xml來指定存取URL所需要的Role，以及透過weblogic.xml來指定User/Group以及Role之間的對應；很明顯的，後者這種方法非常不具備可管理性，因為這樣代表要新增Role就需要重新部署程式^^;

所幸，一般的Commercial Application Server通常都會讓應用程式在部署之後仍然可以動態更改User/Group以及Role。以WebLogic Server來說，這個功能可以直接在管理控制台裡面進行設定，並可以透過這樣的功能設定較一般權限控管更為細微的Policy，讓Role的對應不再只是靜態的存取，而是採取動態的運算來達到。

不過目前的Admin Console有些小問題，會造成所有locale設定成非en語系國家的都會遭遇到一些小錯誤。把語系改變成en_US就可以解決這個問題了。

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WebLogic jCOM Features

以下擷取自BEA Edocs網站對於WebLogic Server jCOM元件的描述：

• WebLogic jCOM hides the existence of the data types accessed by the
  client, dynamically mapping between the most appropriate Java objects
  and COM components.
• WebLogic jCOM supports both late and early binding of object types.
• No native code is required on the machine
  hosting the COM component. Internally, WebLogic jCOM uses the Windows
  DCOM network protocol to provide communication between both local and
  remote COM components and a pure Java environment.
• WebLogic jCOM supports an optional "native mode" which maximizes performance when running on a Windows platform. See DCOM Versus Native Mode.
• WebLogic jCOM supports event handling. For
  example, Java events are accessible from Visual Basic using the
  standard COM event mechanism and Java objects can subscribe to COM
  component events.

最近一直在想一個將COM元件以及WebLogic JMS連結在一起的好辦法，看來jCOM元件的Java←→COM通訊能力很值得期待。

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Weblogic Server: Spring Console設定

自從去年(2005)BEA宣誓力挺Opensource應用程式框架以來，BEA和Spring Framework的Interface21就走的越來越近。除了和Interface21簽訂互相技術支援的合約外，Interface21和bea的工程師更是有許多技術底層的交流。Spring Console就是這樣的交流當中所衍生出來的一種產品。

首先，定位一下什麼是 Spring Console。Spring Console並不是開發時期的工具，而是應用程式部署在Weblogic平台上的一個JMX監控工具。大家都知道，從Spring 1.2以來，我們就可以透過MBeanExporter將任何一個POJO註冊在MBeanServer上成為一個JMX Standard MBean，然後就可以透過MC4J這樣的JMX監控工具來管理這樣的MBean。 Spring Console可以被當作是一個JMX的Web管理介面，只是這個管理介面可以直接內嵌在WebLogic Server 9.x的管理控制台裡頭。這樣的好處是，當管理人員登入到WebLogic Server管理控制台的時候，除了能夠管理一些WebLogic Server例行性的事務之外，還能夠管理跟Application邏輯相關的東西，比方說直接透過Web介面查詢目前的登入人數、工作排程、使用分析等等，如下圖：





講完這個東西的好處後，當然要講一下怎麼安裝。首先：



1. 到BEA網站下載Spring Kit。

2. 解開下載檔之後，可以看到裡頭有一個spring-wls-console-ext的目錄，開啟後可看到有兩個.jar檔：spring-ext-client.jar以及spring-ext-server.jar

3. 將spring-ext-server.jar放到你的DomainHome/console-ext下

4. 將spring-ext-client.jar放到你webapp的WEB-INF/lib下

5. 開發你的Web Application，然後參考這篇文章的applicationContext.xml設定

6. 將WebLogicHome/server/lib/consoleapp/APP-INF/lib中的commons-logging以及log4j的jar檔copy到你的DomainHome/lib下


這樣就搞定啦！

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WebLogic Server: 交易的迷思

一般的程式設計師對於單一資料源的交易處理機制都有一定的了解。所謂的交易控管，用白話文來說，就是只要我需要一次更動多筆資料，而這個更動的行為在邏輯

上是一個具有業務價值的單一行為，我就需要交易的處理機制。但是比較少人花心思去了解的是J2EE裡頭規範Application
Server必須Follow的XA Transaction Protocol以及更具有價值的Transaction Recovery機制。

接下來我想要點出的是一般人的迷思：

1. 迷思：只有在多重資料庫的資料更新場合才需要2PC。事實上只要你有兩個以上的DataSource想要同時參與一個Transaction，你就需要2PC。除非你自行處理所有的交易補償邏輯，否則兩個以上的Local Transaction，是不會有相互關連，資料的正確性也就大大的有問題了。
2. 迷思：只要依賴資料庫的交易機制，我的資料正確性就無懈可擊！
   假設Application Server正在處理一個交易，一個Batch
   update好了。你從DataSource1把資料傾倒到DataSource2，一邊將DataSource1的資料清除掉。這時候，不知道什麼原
   因，網路斷了，或者電源線被踢到了....源源不絕的客服電話把你灌爆。你以為你把電源插上就沒事了，可是.....咦，資料好像不太對？這時候如果你用
   得是WebLogic Server Advantage以上的版本，你可以透過Transaction Log自我恢復的機制，來讓WebLogic
   Server幫你Rollback資料庫裡頭的資料，維護你資料的Consistency。當然，你可以自己花錢花時間寫這個機制....但是你的客戶是
   否可以接受哪怕是幾分鐘的資料不正確？

簡單的結論：除非你的AP只提供簡單的查詢介面，否則你幾乎一定會需要用到2PC以及
Transaction
Recovery的功能。Transaction的問題很難Debug，已經看到太多英才死在這邊了，拜託大家緬懷先列的犧牲，不要再為了這種問題而強制
性失眠了，請愛用XA，謝謝！

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