Apple WebObjects 3.5 - Manual (Page 100)

Chapter 6 Creating Reusable Components
100
The parentAction attribute identifies a callback method, one that the child
component invokes in the parent when the user clicks the Yes or No link. The
exitStatus attribute identifies a variable that the parent can check to discover which
of the two links was clicked. This attribute passes state information from the
child to the parent. A reusable component can have any number of callback and
state attributes, and they can have any name you choose.
Now let’s look at the revised child component. The template file for the
AlertPanel component has to declare the positions of the added Yes and No
hyperlinks. (Only excerpts of the implementation files are shown here.)
Child's Template File (excerpt)
The corresponding declarations file binds these declarations to scripted
methods:
Child's Declarations File (excerpt)
NOCHOICE: WOHyperlink {
action = rejectChoice;
string = "No";
};
YESCHOICE: WOHyperlink {
action = acceptChoice;
string = "Yes";
};
And the script file contains the implementations of the rejectChoice and acceptChoice
methods:
Child's Script File (excerpt)
id exitStatus;
id parentAction;
- rejectChoice {
exitStatus = NO;
return [self performParentAction:parentAction];
}
- acceptChoice {
exitStatus = YES;
return [self performParentAction:parentAction];
}
Note that exitStatus and parentAction are simply component variables. Depending on
the method invoked, exitStatus can have the values YES or NO. The parentAction
variable stores the name of the method in the parent component that will be