Apple WebObjects 3.5 User Manual

Page 70

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Chapter 5

WebObjects Viewed Through Its Classes

70

Figure 17. Request-Response Loop: Page Level

Two major branches of these objects descend from WOElement:
WOComponent objects, which represent components, and
WODynamicElement objects, which represent dynamic HTML elements on
the page. For details on how this happens and for more on these classes, see
“How HTML Pages Are Generated” (page 82).

Four classes are involved at this level:

WOComponent (in Java, Component)

Represents a integral, reusable page (or portion of a page) for display in a
web browser.

WOElement (in Java, Element)

Declares the three request-handling methods:

takeValuesFromRequest:inContext:

,

invokeActionForRequest:inContext:

, and

appendToResponse:inContext:

. WOElement is an

abstract class. Each node in an object graph, which represents the HTML
elements of a component and their relationships, is an object that inherits
from WOElement.

WODynamicElement (in Java, DynamicElement)

An abstract class for subclasses that generate particular dynamic elements.

HTTP server

adaptor

Request

Response

response

page

transaction 1

request

page

session 1

response

page

transaction 2

request

page

application

session store

session 2

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