Creating Custom UI Components and Other Custom Objects - The Java EE 6 Tutorial: Advanced Topics - page 104

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<bookstore:area id="map1" value ="#{Book201}"
onmouseover="resources/images/book_201.jpg"
onmouseout="resources/images/book_all.jpg"
targetImage="mapImage" />
To reference the ImageArea model object bean values from the component class,
you implement a getValue method in the component class. This method calls su-
per.getValue . The superclass of tut-install /examples/case-studies/
dukes-bookstore/src/java/dukesbookstore/components/AreaCom-
ponent.java , UIOutput , has a getValue method that does the work of finding the
ImageArea object associated with AreaComponent . The AreaRenderer class,
which needs to render the alt , shape , and coords values from the ImageArea ob-
ject, calls the getValue method of AreaComponent to retrieve the ImageArea ob-
ject.
ImageArea iarea = (ImageArea) area.getValue();
ImageArea is a simple bean, so you can access the shape, coordinates, and alternative
text values by calling the appropriate accessor methods of ImageArea . “ Creating the
Renderer Class ” on page 115 explains how to do this in the AreaRenderer class.
Summary of the Image Map Application Classes
Table 6-2 summarizes all the classes needed to implement the image map component.