Apple WebObjects 3.5 Manual de usuario descargar pdf (Pagina 50)

Chapter 2 Enhancing Your Application

3. At the top of the Application class deﬁnition, enter this declaration:

protected MutableVector allGuests;

This declares allGuests to be of type MutableVector. Declaring it

protected means that it is accessible only from this class or one of its

subclasses. It is standard object-oriented practice for a class to prevent

other classes from directly manipulating its instance variables. Instead,

you provide accessor methods that other objects use to read or modify the

instance variables.

4. Add the accessor methods

addGuest and clearGuests, as shown in the ﬁgure.

The

addGuest method adds an object of class Guest to the end of the allGuests

array, using the MutableVector method

addElement (its Objective-C

equivalent is

addObject).

The

clearGuests method removes all the objects from the array using the

MutableVector method

removeAllElements (its Objective-C equivalent is

removeAllObjects).

5. Save

Application.java.

Adding Guests to the Guest List

Now, when the user submits the form, you’ll add the information to the allGuests

array rather than displaying it directly.

1. Switch to the code for

Main.java.

2. In the

submit method, add the following code before the return statement:

((Application)application()).addGuest(currentGuest);

currentGuest = new Guest();

This code calls the application’s addGuest method, which adds an object (in

this case,

currentGuest) to the end of the array. Then it creates a new Guest

object to hold the next guest’s data.

Note: The addGuest method is deﬁned in the class Application, which is a

subclass of WebApplication. The component’s

application method (called in

the above statement) returns an object of type WebApplication, so you

must cast it to Application in order to access its

addGuest method.

Your next step is to create a new component to display the list of guests that

allGuests stores.

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Apple WebObjects 3.5 Manual de usuario Pagina 50

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