Users can access the portal from traditional and wireless devices. Developers can access the portal from the exposed APIs via SOAP, RMI, and our custom tunneling classes.
客戶程序可以通過傳統(tǒng)的或者無線設備來訪問Liferay門戶。而開發(fā)者能夠通過開放的SOAP、RMI以及Liferay提供客戶隧道（tunnel）類來實現對門戶的訪問。

Liferay is designed to deploy portlets that adhere to the Portlet API (JSR 168). Many useful portlets are bundled with the portal (Mail, Document Library, Calendar, Message Boards, to name a few) and can be used as examples for adding your own custom portlets.

All HTTP and WAP requests go through MainServlet which extends the basic Struts ActionServlet. MainServlet processes all requests and ensures that each request is routed to the proper PortletAction. Refer to Struts for a better understanding of how the portal‘s web framework functions.
Liferay門戶通過擴展struts的基本類ActionServlet生成自己的MainServlet類，而所有的HTTP或WAP請求都要提交給這個類來處理，以保證能傳遞給合適的PortletAction來處理?？赡軈㈤?/SPAN>Struts，進一步學習理解WEB架構的實現原理。
All layout information for the portal is centralized in two files: portal_layout.jsp and portlet_layout.jsp. They can be found in /portal-web/docroot/WEB-INF/html/tiles. Refer to articles about Tiles to get a better understanding of how Tiles works as a layout manager.

Liferay is no longer dependent on EJBs and can be deployed on a standalone servlet container. All business logic is concentrated inside POJO implementations that are looked up and instantiated by Spring. These implementations can be modified or enhanced via Spring‘s AOP and IOC capabilities.
Liferay不再依賴于EJB，它完全可以單獨裝配到一個servlet容器（如：Tomcat,JBoss等）中。而所有的業(yè)務邏輯都通過Spring管理的POJO來實現。這樣的實現利益于Spring的AOP各IOC特性。
The enterprise release of the portal wraps the POJO implementations with Session EJBs to provide heavy scaling and transaction support required by large sites. The professional release of the portal calls the POJO implementations directly to provide a light weight facade.
但在POJO的實現方法上Liferay的兩個版本有所不同，企業(yè)版（enterprise）中通過EJB從而為大站點提供了高擴展性各良好的事務支持能力（如集群），而專業(yè)版（professiona）直接通過輕量級的接口完成。
All data is persisted using Hibernate and is called through the POJO implementations. Liferay used to rely on CMP technology to achieve persistence, but switched over to Hibernate because of its raw speed and flexibility. Liferay is database agnostic and can run on a variety of popular databases.
所有的業(yè)務數據都通過Hibernate來實現并通過POJO來調用。Liferay曾經使用CMP技術.來實現持久層，但后來因速度及靈活性等原因改用Hibernate。在數據庫方面，Liferay也完全兼容大多數主流類型DB。
Liferay uses JAAS Web security so that when a user logs in, their principal is propogated to the Servlet and EJB tiers. Remote Session EJBs can take advantage of this by checking security and permissions at the EJB level so it does not have be duplicated else where. Local Session EJBs exposes business logic to other Session EJBs and does not specifically check for security since they cannot be called remotely. Principals are also propagated to POJO implementations that are the base classes for Remote Session EJBs.
Liferay使用JAAS來完成用戶認證安全管理，好處是當一個用戶登錄后，它的安全屬性可以在Servlet和EJB層中沿用，真正作到系統(tǒng)級的SSO。具體講，遠程EJB可以沿用安全檢查及權限屬性，本地的EJB是為其它EJB提供業(yè)務邏輯服務的，不能被遠程調用所以也不必做此類檢查；安全原則也派生到POJO實現中，而這此實現其實是遠程EJB的基礎類。
The enterprise release uses Session EJBs which allows the deployer to separate the Web server, EJB server, and database server to achieve clustering at three levels. This is true n-tier deploying because no one is forced to cluster at any single layer and allows the most flexibility for large companies.
企業(yè)版式使用EJB，所以系統(tǒng)分別可以在WEB服務器、EJB服務器、數據庫服務器三層中實現集群。當然在n層的系統(tǒng)中，集群也保持優(yōu)勢，而且在每一層都并不強迫使用集群，這些都為大企業(yè)應用提供了極好的彈性選擇權。
Most of our EJBs, HBMs, and Models are generated through the ant task build-ejb which reads the file ejb.xml in /portal-ejb. Each portlet that persist data has its own ejb.xml (do a search in /portal-ejb and you will get a list back). We copy this file to /portal-ejb when we want to generate the persistence classes for that portlet. This is an internal tool that is built on top of the XDoclet engine.
系統(tǒng)中的EJB、HBM、以及模式Model者是ant執(zhí)行build-ejb任務時，通過讀取目錄/portal-ejb下的ejb.xml文件，然后自動生成的。每個有持久層對象的門戶單元（portlet）都有自己的ejb.xml文件（可以在/portal-ejb下搜索得到清單）。當需要生成持久層的類時，就把文件復制到/portal-ejb下，這生成工具是建立在XDoclet之上的。
For example, upon reading ejb.xml found in the Bookmarks portlet, the following model classes are generated. Each model class reflects a table in the database. Never edit BookmarksEntryModel. Do edit BookmarksEntry to add hand massaged code. BookmarksEntry is generated once and extends BookmarksEntryModel. This allows us the ease of generated code and flexibility of hand massaged code.
例如：通過讀取Bookmarks門戶單元的ejb.xml文件配置后，自動生成下列的模式類。每個類對應數據庫中的一個表。永遠不要手工修改BookmarksEntryModel類，而要通過修改BookmarksEntry，然后再更新BookmarksEntryModel內容。這樣做的好處是減少了直接寫代碼的工作，而只做相應的標記工作。
com.liferay.portlet.bookmarks.model.BookmarksEntry
com.liferay.portlet.bookmarks.model.BookmarksEntryModel
com.liferay.portlet.bookmarks.model.BookmarksFolder
com.liferay.portlet.bookmarks.model.BookmarksFolderModel

Hibernate classes are generated that map to the model classes. This allows for an n-tier architecture for cases where your model classes are marshalled across the wire and your Hibernate classes are not.
Hibernate類是根據模式（model）類對應生成的。這樣就可以在多層系統(tǒng)中允許模式類是可作序列化處理的，而Hibernate類則不必。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryHBM
com.liferay.portlet.bookmarks.ejb.BookmarksFolderHBM

Persistence methods to add, update, delete, find, remove, and count the Hibernate entries are generated as the default persistence mechaninsm.
持久層的方法如：add, update, delete, find, remove, 以及count，系統(tǒng)都默認自動生成。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryPersistence
com.liferay.portlet.bookmarks.ejb.BookmarksFolderPersistence

Helper classes are generated that call the persistence methods. By default, the helper classes call the Hibernate persistence methods to update the database. You can override this in portal.properties and set your own persistence class as long as it extends the default persistence class. This means you can customize where you store your data. It can be a traditional database, a LDAP server, or even something else.
也生成了專門的協(xié)助類（Helper classes），可以用來調用持久層方法。默認時，協(xié)助類調用Hibernate的方法來對數據庫進行更新操作，但是也可以改寫portal.properties中的配置，使用自己專用的類來完成，但這種類要求要繼承默認的持久層類。換言之，用戶完全可以定制自己的持久層數據，可以是一個正統(tǒng)的數據庫，或者是LDAP服務器，其它什么的。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryUtil
com.liferay.portlet.bookmarks.ejb.BookmarksFolderUtil

Pooling classes are also created to minimize object creation. Behavior can be modified in portal.properties.
為了減少對象生成的成本，引入了對象池，可以通過修改portal.properties文件來控制池的基本動作。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryPool
com.liferay.portlet.bookmarks.ejb.BookmarksFolderPool

POJO implementations that extend PrincipalBean are generated to hold business logic that check the caller principal and can be called remotely. Calling getUserId() returns the user id of the current user. Calling getUser() returns the User model that represents the current user. The Session EJB that extends the POJO implementation implements PrincipalSessionBean.
用來實現業(yè)務邏輯的POJＯ類，通過繼承PrincipalBean類，來實現有關調用者的方法，所以可以遠程調用。如：調用getUserId()可以得到當前用戶的ID；調用getUser()則返回當前用戶的對象。EJB再繼承這類POJO，實現遠程調用。
For example, these classes allow you to delete a bookmark entry or folder if and only if you are the creator of that entry or folder.
例如：下面的類實現了，允許當且公當bookmark項目或目錄的生成者可以刪除它。這些對象只有在不存在時才可能被創(chuàng)建。
These classes are only generated once if they do not already exist.

com.liferay.portlet.bookmarks.ejb.BookmarksEntryManagerImpl
com.liferay.portlet.bookmarks.ejb.BookmarksFolderManagerImpl

Helper classes are generated based on the POJO implementations. They help save developer time and prevent polluted code. Instead of writing many lines of code just to look up the appropriate Session EJB wrapper or POJO implementation, you simply call BookmarksEntryManagerUtil.addEntry to call the equivalent method in BookmarksEntryManagerImpl.addEntry.
協(xié)助類（Helper classes）是在POJO的實現基礎上生成的。它可以節(jié)約開發(fā)者的工作，不必書寫很多行的代碼，而只要簡單的找到合適的EJB wrapper或POJO實現，通過調用BookmarksEntryManagerUtil.addEntry來間接調用相應的BookmarksEntryManagerImpl.addEntry方法就可以了。
BookmarksEntryManagerUtil calls BookmarksFolderManagerFactory to look up the class that implements BookmarksEntryManager. BookmarksFolderManagerFactory defers to Spring and settings in portal.properties on whether to load the Session EJB wrapper or the plain POJO implementation. The Session EJB extends the POJO implementation.
BookmarksEntryManagerUtil通過調用BookmarksFolderManagerFactory來查找實現BookmarksEntryManager的類。也正是通過BookmarksFolderManagerFactory來識別Spring和portal.properties中的配置來決定要是載入EJB wrapper還是POJO實現。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryManager
com.liferay.portlet.bookmarks.ejb.BookmarksEntryManagerEJB
com.liferay.portlet.bookmarks.ejb.BookmarksEntryManagerEJBImpl
com.liferay.portlet.bookmarks.ejb.BookmarksEntryManagerFactory
com.liferay.portlet.bookmarks.ejb.BookmarksEntryManagerHome
com.liferay.portlet.bookmarks.ejb.BookmarksEntryManagerUtil
com.liferay.portlet.bookmarks.ejb.BookmarksFolderManager
com.liferay.portlet.bookmarks.ejb.BookmarksFolderManagerEJB
com.liferay.portlet.bookmarks.ejb.BookmarksFolderManagerEJBImpl
com.liferay.portlet.bookmarks.ejb.BookmarksFolderManagerFactory
com.liferay.portlet.bookmarks.ejb.BookmarksFolderManagerHome
com.liferay.portlet.bookmarks.ejb.BookmarksFolderManagerUtil

Tunneling classes are generated so that developers can call the POJO implementations over port 80. An example of this given in the section V of this document.
隧道類（Tunneling classes）是用來實現通過80端口來調用POJO的。在本文檔的第V部分有一個例子。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryManagerHttp
com.liferay.portlet.bookmarks.ejb.BookmarksFolderManagerHttp

Soap classes are generated so that developers can call the POJO implementations over port 80. Soap is slower than tunneling because tunneling streams requests in binary format. Soap is more flexible than tunneling because the client classes are not limited to Java.
Soap類也是用來實現通過80端口來調用POJO的。雖然與隧道類相比Soap類在速度上要差一點，原因是隧道類使用二進制數據流。但Soap類用靈活，可以適用各種客戶端（不局限于Java）。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryManagerSoap
com.liferay.portlet.bookmarks.ejb.BookmarksFolderManagerSoap

POJO implementations classes that do not extend PrincipalBean are generated to hold business logic that do not check the caller principal and can be called locally. These classes exist so that business logic can be easily integrated with other projects.
當地的POJO為類實現，并不繼承PrincipalBean類，實現業(yè)務邏輯時也不檢驗調用者的身份。這種類使得可以更容易地與其它的項目集成。
These classes are only generated once if they do not already exist.
這些類只有在檢驗到不存在時才會被創(chuàng)建。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryLocalManagerImpl
com.liferay.portlet.bookmarks.ejb.BookmarksFolderLocalManagerImpl

Helper classes are also generated.
同時協(xié)助類也生成了。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryLocalManager
com.liferay.portlet.bookmarks.ejb.BookmarksEntryLocalManagerEJB
com.liferay.portlet.bookmarks.ejb.BookmarksEntryLocalManagerEJBImpl
com.liferay.portlet.bookmarks.ejb.BookmarksEntryLocalManagerFactory
com.liferay.portlet.bookmarks.ejb.BookmarksEntryLocalManagerHome
com.liferay.portlet.bookmarks.ejb.BookmarksEntryLocalManagerUtil
com.liferay.portlet.bookmarks.ejb.BookmarksFolderLocalManager
com.liferay.portlet.bookmarks.ejb.BookmarksFolderLocalManagerEJB
com.liferay.portlet.bookmarks.ejb.BookmarksFolderLocalManagerEJBImpl
com.liferay.portlet.bookmarks.ejb.BookmarksFolderLocalManagerFactory
com.liferay.portlet.bookmarks.ejb.BookmarksFolderLocalManagerHome
com.liferay.portlet.bookmarks.ejb.BookmarksFolderLocalManagerUtil

Some of our users needed to call the Local Manager classes remotely, so Remote Manager classes that parallel their Local counterparts are also generated.
但總有一些用戶需要調用引種當地類，于是完全相對應的遠程類也應用而生了。
com.liferay.portlet.bookmarks.ejb.BookmarksEntryRemoteManager
com.liferay.portlet.bookmarks.ejb.BookmarksEntryRemoteManagerEJB
com.liferay.portlet.bookmarks.ejb.BookmarksEntryRemoteManagerEJBImpl
com.liferay.portlet.bookmarks.ejb.BookmarksEntryRemoteManagerFactory
com.liferay.portlet.bookmarks.ejb.BookmarksEntryRemoteManagerHome
com.liferay.portlet.bookmarks.ejb.BookmarksEntryRemoteManagerUtil
com.liferay.portlet.bookmarks.ejb.BookmarksFolderRemoteManager
com.liferay.portlet.bookmarks.ejb.BookmarksFolderRemoteManagerEJB
com.liferay.portlet.bookmarks.ejb.BookmarksFolderRemoteManagerEJBImpl
com.liferay.portlet.bookmarks.ejb.BookmarksFolderRemoteManagerFactory
com.liferay.portlet.bookmarks.ejb.BookmarksFolderRemoteManagerHome
com.liferay.portlet.bookmarks.ejb.BookmarksFolderRemoteManagerUtil

A lot of people stay away from Session EJBs because they are heavy and require a lot of coding. Our build scripts show that you can leverage the advantages of Session EJBs while minimizing repetitive labor so that you can strike a good balance between effort and results.
許多人避免使用EJB，因為它的重量級，需要大量的代碼工作。Liferay的自動生成腳本可以使得，既不損失EJB的優(yōu)點，而且還最小化重復的代碼等工作，從而你可以在努力與結果之間找到一個良好的平衡點。
Spring gives Liferay additional flexibility. Developers can test their POJO implementations with Liferay Portal Professional in a servlet container and deploy to production with Liferay Portal Enterprise in an application server.

All of our remote POJO implementations are exposed to the external world via SOAP, RMI, and our custom tunneling classes.
通過SOAP, RMI, 以及我們客戶化的隧道類等途徑，所有的遠程POJO實現都向外開放。
We do not do this simply because Web services is a buzz word, but because we find it extremely useful for integration. The following is an example of a company that leveraged these resources.
之所以這么做，并不僅僅是因為網絡服務要應用于商務，而是根本上我們發(fā)現這樣做對集成來說簡直是太有用了。以下就有一個得益于此的企業(yè)集成案例。
3sixteen is a t-shirt company that needed to get up and running fast. They saw Liferay and wanted to use the integrated Shopping portlet. However, they thought that Liferay was too ugly for a t-shirt company that prided itself on being at the cutting edge of fashion. To solve this problem, they decided to separate their web presence into two sites: a brochure site and shopping site.
3sixteen是一個做服裝T恤的公司，需要擴大發(fā)展。他們注意到了Liferay有意用之來集成一個商業(yè)門戶。但是，他們又感覺在一個超前時尚的服務行業(yè)Liferay似乎顯得有點太丑了，或者說不入格。為了解決這個矛盾，他們不得以把WEB表現層分成了兩個站點：一個產品展示站點和一個在線購買站點。
www. became the pretty site built in Flash and my. became the shopping site using the vanilla Liferay distribution. These two sites are hosted on two different Linux machines and for all intents and purposes could have resided on different continents.
結果，www.成了一個基于Flash技術的漂亮站點，而my.則是一個基于Liferay的vanilla版本的在線購物站點。這兩個站點分別安裝在不同的兩個Linux主機上，基于目標及用途的考慮可以布署在不同的國家。
They also needed to build a mailing list to collect email addresses for all their interested customers. To accomplish this, they added a JSP pop up box on their Flash site that would tell the portal server to add the email address to a contact in the Address Book portlet.
項目的一個重要需求是要建立一個郵件地址管理系統(tǒng)，用來收集目標客戶的郵件地址。于是，在Flash作的站點中我們加入了彈出工窗口，用來通過門戶服務器要增加記錄某客戶的這個郵件地址到系統(tǒng)中。
The following is a JSP snippet that shows how the guys at 3sixteen leveraged ABContactManagerHttp to add a contact.
以下是相應的JSP片段，它利用ABContactManagerHttp的功能來增加新的聯系人。

ABContactManagerHttp invoked addContact in ABContactManagerUtil. The invokation was sent over port 80 and received by http://my./tunnel/servlet/AuthTunnelServlet. The application server made sure the authentication matched and then processed ABContactManagerUtil as if the user with the id joe_bloggs was calling addContact. ABContactManagerUtil then called ABContactManagerImpl to do the actual work. You can trace the logic of this by viewing the source included in the generated JavaDocs.
ABContactManagerHttp調用了ABContactManagerUtil中的addContact方法，而重要的是這個調用是通過80端口，直接由門戶站點的http://my./tunnel/servlet/AuthTunnelServlet接收，應用服務器只要判定認證合法之后，就以ID是joe_bloggs的用戶的身份調用addContact方法，然后由ABContactManagerUtil調用實現類ABContactManagerImpl來完成真正的添加聯系人的工作。這一過程可能通過查自動生成的JavaDocs文檔中的源代碼來證實。
Now Joe Bloggs can log into the portal and look in his Address Book portlet to see that he has a new contact. All of the included portlets have this capability because these helper classses are generated. This means you can write applets or any other Java application to access the Session EJBs that contain your business logic. This can be a security hazard if someone had your password, so you can configure to limit the Tunnel Servlet to only listen on certain ports by editing portal.properties.
之后呢，那個Joe Bloggs就可以登錄門戶，通過查看它的地址本發(fā)現多了一個新的聯系人了。而且在系統(tǒng)的其它門戶單元也可以通過協(xié)助類（helper classses）達到同樣的目的。而另外一方面這也可能是一個安全隱患，因為隨便一個人就可以通過一個小JAVA（applets）或其它程序，從而直接調用有業(yè)務邏輯功能的EJB，只要他擁有認證的密碼。一個應對的方法是通過修改portal.properties來只指定特定的端口偵聽這類服務請求。
You can also access the Session EJBs over SOAP and RMI. We will post more examples of that shortly.

Liferay was built from the ground up to be used by application service providers. The following is a sample list of portals running off of one portal instance hitting one database and shows the capabilities of Liferay.
Liferay是一個自下而上完整的應用系統(tǒng)提供者。以下是案例清單，它們都是單一門戶單一數據庫系統(tǒng)。
http://demo.
http://my.
http://my.
http://portal.
http://www.
http://www.

Users in each of these portals have no information about the other portals. They are separated by domain and each portal exists in its own space based on the company‘s id.
其中每個門戶的用戶都與其它門戶完全隔離，門戶間是依據各自的公司ID通過域來分割不同的空間。
See Multiple Portals for detailed informaton on how to set up multiple instances of Liferay on one machine.
如果對在同一機器集成多個Liferay有興趣，請參閱Multiple Portals。