什麼是Portal?
A server to aggregate content
A scalable infrastructure
A framework to build portal components and extensions
A scalable infrastructure
A framework to build portal components and extensions
The main job of a portal is to aggregate content and functionality.
這句話把Portal的最基本要實現的目標寫了出來。“集合內容和功能”。在這裏內容是指的很廣泛的一個概念，內容可以EIS，也可以是文件服務器，等等是個非常複雜和廣泛的內容。“功能”，爲了實現功能的聚合，framework，scalable infrastructure是portal的重要特性。
Personalization enables the portal to deliver user-specific information targeting a
user based on their unique information
user based on their unique information
organize the look and feel of the portal to suit their individual needs and tastes.
Portal發展的四個里程
1。The first portals, known as first generation portals, were focused on providing static Web content, Web documents and live feeds.
2。Second generation portals are first generation portals with added features such as personalized, customized content and a search capability but are often a manual roll-your-own process.
3。Collaboration portals provide the ability for teams to work in a virtual office. They provide content management services, the mining and organization of related information, along with collaborative services that allow users to chat, e-mail,share calendars and define user communities.
4。This involves integration with legacy applications at the component level.They take portals beyond the corporate boundaries for use by employees,suppliers and customers. They also provide access from multiple types ofIBM WebSphere Portal Toolkit V5 devices to address the diverse user communities in need of services.
重點是第四點，我是這麼理解的，功能構件化，組件化，portal的架構特點保證了用戶可以二次開發和使用別人開發的組件。客戶端的多樣化，除了可以滿足不同種類的用戶，也可以滿足不同客戶端的訪問要求。
關於Portal和Portlet的關係，我覺得下面這段話寫的比較好。
Portlets are similar to Windows applications in that they present their contents in a window-like display on a portal page. Like a Windows application, the portlet window has a title bar which contains controls,allowing the users to expand (maximize) and shrink (minimize) the application.
Portal就像windows一樣，而portlet就像windows中開發的應用程序，應用程序實現一定的功能，不過它要調用windows api來實現這些功能，這包括應用程序的顯示，事件的處理，數據處理等等。同樣道理，portlet可以實現一些業務流程和功能，但是它是建立在portal的基礎上的，才能被用戶正常使用。
The portal infrastructure provides the core sets of services required by the portlets,including:
Access to user profile information
A framework for portlets to participate in events
A framework to communicate with other portlets
Access to remote content
Access to credentials
A framework for storing persistent data.
A framework for portlets to participate in events
A framework to communicate with other portlets
Access to remote content
Access to credentials
A framework for storing persistent data.
以WCM Authoring Portlet爲例，它需要訪問操作用戶的信息，比如在編輯歷史，編輯權限方面就需要Portal向它提供用戶管理的接口。WCM Authoring中有許多操作，這些事件需要portal提供的事件監聽體系來處理這些事件。如何存儲內容也需要portal來提供一定的接口，WCM主要使用的是JCR。
Local Rendering Portlet,Remote Rendering Portlet需要Access to remote content，A framework to communicate with other portlets，Access to credentials來實現內容的rendering.
