Apple WebObjects 3.5 Bedienungsanleitung PDF herunterladen (Seite 97)

Beneﬁts of Reusable Components

Figure 28. An Alert Panel

This panel is similar to the navigation table shown in Figure 27, but as you’ll

see, most of the component’s attributes are customizable.

To use this component, you simply declare its position within the HTML

page and give it a name:

<HTML>

<HEAD>

<TITLE>Alert</TITLE>

</HEAD>

<BODY>

</BODY>

</HTML>

The declarations ﬁle speciﬁes the value for each of the panel’s attributes,

either by assigning a constant value or by binding the attributes value to a

variable in the component’s code (as with the

alertString and infoString attributes

here):

ALERT: AlertPanel {

alertString = alertTitle;

alertFontColor = "#A00000";

alertFontSize = 6;

infoString = alertDescription;

infoFontSize = 4;

infoFontColor = "#500000";

tableWidth = "50%";

};

The component’s code deﬁnes the alertTitle and alertDescription instance

variables or methods, which set the text that’s displayed in the upper and

lower panes of the alert panel. The

alertDescription method could, for example,

consult a database to determine the release date of the video.

WebObjects Builder makes working with reusable components such as

AlertPanel even easier. Component clients can simply drag the alert panel

into their components and use the Inspector to set the bindings. They don’t

need to manually edit the declarations ﬁle to set these bindings. To set this

up, you, as the component creator, edit a ﬁle named

AlertPanel.api specifying

both required and optional attributes. You could, for example, export only

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Apple WebObjects 3.5 Bedienungsanleitung Seite 97