Oracle Forms Services Architecture

Oracle Forms Services Architecture

Author:                         PTIAN(tianpan@gmail.com)

Creation Date:            05/01/2012

Last Updated:             

Version:                        

Status:                           

Contents

Forms Services Architecture                                                                                                                                                                       1

Summary                                                                                                                                                                                                          1

Forms Servlet                                                                                                                                                                                                   1

Form Applet                                                                                                                                                                                                    2

Forms Listener Servlet                                                                                                                                                                                  3

Forms Runtime Engine                                                                                                                                                                                3

A Complete Process                                                                                                                                                                                      3

Reference                                                                                                                                                                                                          5

 

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Forms Services Architecture

Summary

Oracle EBS Form架构 (Forms Services Architecture) 是典型的三层, 所有客户端触发的 Trigger的处理都发生在 DB层和应用服务器层。 Forms Services Architecture 主要包括四大组件： the Forms Servlet, the Java Applet(Forms Client), the Forms Listener Servlet, and the Forms Runtime Engine

Forms Servlet

Form Servlet是一个 Java Servlet，运行于 Oracle HTTP Server 中，用于为客户端创建动态 HTML

Form Applet

Form Applet是一个 Java Applet, 提供界面来展示 (交互 )Form Runtime Engine.

Applet采用 Java 创建的基于 HTML的程序。浏览器将其暂时下载到用户的硬盘上，并在 Web 页打开时在本地运行。含有 Applet 的网页的HTML 文件代码中部带有 <applet>和</applet> 这样一对标记，当支持 Java 的网络浏览器遇到这对标记时，就将下载相应的小应用程序代码并在本地计算机上执行该 Applet 。

查看EBS Applet 的初始页面的源代码

可以看到，确实是有 <applet> 和 </applet> 这样一对标记 ,

code="oracle.forms.engine.Main" 是要运行的 Java Applet Class，

这个Java类在fndforms.jar中（fndforms.jar会在Applet启动前预加载）

codebase="/OA_JAVA/", 给出Class 所在的位置

archive="/OA_JAVA/oracle/apps/fnd/jar/fndforms.jar, /OA_JAVA/oracle/apps/fnd/jar/fndformsi18n.jar,….” 是指Applet 运行前，需要预加载的 jar 文件

<PARAM name=serverArgs    value="module=/slot/ems2384/appmgr/apps/apps_st/appl/fnd/12.0.0/forms/US/FNDSCSGN….> 说明，Applet 打算加载的第一个 Form 文件是FNDSCSGN.fmb

打开FNDSCSGN.fmb 就可以看到，这个 form 实际上EBS 的 Navigator的主界面

Forms Listener Servlet

Form Listener Servlet也是一个 Java Servlet ，它运行在支持 Servlet引擎的 Web Server 中（例如OC4J ）。 Form Listener Servlet负责管理每一个 Forms Runtime process ，通过Web Server 管理 Client和 Forms Runtime Process 的交互。

Forms Runtime Engine

Form Runtime Engine是运行于 App Server 上的一个进程，这个进程是有 Form Listener Servlet 触发的。Forms Runtime Engine 是真正处理所有业务逻辑和 Form 功能的地方。 fmx,plx,mmx这些“可执行文件”就是被 Form Runtime Engine 调用的。

It is important to understand that all of the Forms logic is executed by the Forms Runtime Engine running on this middle tier. That is, the Forms Runtime Engine opens the appropriate FMX file, connects to the database and executes the Form. No logic executes on the client. Only what Oracle classes as UI information is sent to the client. Each major action on the client, such as navigating between  Form fields, choosing an item from a list, etc, incurs a round trip to the Application server in order to be processed by the Forms Runtime Engine.

--Oracle Web Forms(http://doc.xmarc.net/xmarc6/es/Fire/fug/webforms.htm)

A Complete Process

大体过程：首先用户通过浏览器输入 Application 的网址(eg. http://domain:port/forms/frmservlet)，然后 HTTP Server 中Form Servlet 接收请求之后，生成一个 HTML文件并传回到客户端 (生成的过程实际上是在静态网页的基础上加入和环境相关的变量 )，这个 HTML文件是包含 <Applet> 程序的，这个Applet 就是用来展示 Form的容器，同时应用程序的逻辑是执行在 Middle Server 层上。

接下来是一个详细的运行时过程

1] 在浏览器中输入 URL ，准备访问 Form应用

http://domain:port/forms/frmservlet

2]中间层的 HTTP 服务器接收到用户请求之后， 再通知Form Servlet 。

3] Forms Servlet 为客户端动态产生一个 HTML 页面， 这个页面包含启动 Form 的所有信息。

就像之前提到的，可以打开这个 HTML 页面源代码，就可以看到里面的细节。

4] 如果是第一次登陆的话，想要运行 HTML 中的Applet ，就必须先通过 HTTP Server 下载相应的 jar文件 (HTML 页面的源代码中 archive部分 ) 。

5] Applet启动后 ( 一般会先运行 FNDSCSGN.fmb(Navigator Form))， Applet 这是会通知 Forms Listener Servlet， Forms Listener Servlet 然后会在中间层启动一个 Forms Runtime Engine Session。

6] Forms Listener Servlet建立一个 Form Runtime Engine 的连接, Form Runtime Engine 会连接数据库并且加载运行时文件 (fmb,plx,mmx 文件)

7] Forms applet展示加载的 Form.

8] Forms Listener Servlet通过 OC4J 或者HTTP Server 管理 Form Applet和 Form Runtime Engine 的交互。

Reference

J2EE, Web Services, and Internet Applications

http://docs.oracle.com/cd/B10464_05/core.904/b10375/webstapp.htm

Oracle Web Forms

http://doc.xmarc.net/xmarc6/es/Fire/fug/webforms.htm

 

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