Table of Contents Previous Section

The Ingredients of a WebObjects Application

A typical WebObjects application contains the following ingredients:

• Components that specify the content, presentation, and behavior of an application's pages.
  

• WebObjects Classes that provide an infrastructure for Web-based applications.
  

• DefaultApp, a program that runs as a specified WebObjects application. It receives incoming requests and responds to them using the components you provide.
  

WebObjects provides the classes and the DefaultApp. After installing the WebObjects package, they're ready to go.

You provide the components.

Components

Components are the part of a WebObjects application that you write. Each component is a collection of files that defines the content, presentation, and behavior of a page. Components are comprised of three files:

• An HTML template that specifies how the corresponding page looks. HTML templates contain markup elements that define the format for both static and dynamic page content.
  

• A script file that implements application behavior specific to the component. Generally, script files declare variables for managing dynamic page content and actions that define responses to user requests.
  

• A declarations file that defines a mapping between the HTML template and script variables and actions.
  

The files of a component are organized in a component directory. The name of the directory has the same base name as the name of the component, but it has the extension .wo. For example, the Hello World example has a component named Main and a corresponding component directory named Main.wo.

The template, script, and declarations files in the component directory also have the same base name, and each file type has its own extension. Template files have the extension .html, declarations have the extension .wod, and scripts have the extension .wos. Thus, the Main component has the files Main.html, Main.wos, and Main.wod.

Figure 3 The Contents of a Component Directory

Note: Not all components represent an entire page. Some components represent only a portion of a page. You can extract common data and functionality from components for whole pages into smaller, reusable components. These smaller components can be nested as subcomponents inside a component representing a whole page. For more information on writing and using reusable components, see Writing Reusable Components.

Where WebObjects Components Go

Generally, you put the components of a WebObjects application in a directory with the same name as the application. For example, the Hello World example has a corresponding directory named HelloWorld that contains its component directories.

WebObjects application directories such as the HelloWorld directory can go anywhere under the <DocumentRoot>/WebObjects directory. You can create application directories immediately under <DocumentRoot>/WebObjects, or you can create hierarchies of directories within <DocumentRoot>/WebObjects to organize application directories however you wish.

As shown in Figure 6, the Hello World application directory is located in <DocumentRoot>/WebObjects/Examples.

Reusable WebObjects components used by multiple applications aren't usually kept in application directories. Rather, they are located directly under <DocumentRoot>/WebObjects so they can be accessed by all the applications that use them.

Hello World Application Directory

Table of Contents Next Section