Question

I am studying Spring WebFlow, and I am apparently missing a key concept of Spring in a sample application I am studying. I have the following XML which gets the property allItems from a shopping cart.

<on-start>
    <evaluate expression="order.setBooksOrdered(shoppingCart.allItems)" />
</on-start>

However, I do not see a method or property by that name in the ShoppingCart class below. Although of course there is a getAllITems() class. It all compiles and works, but I am apparently missing a key concept here.

@Component
@Scope("session")
public class ShoppingCart implements Serializable {
    private List<Book> shopping = new ArrayList<Book>();

    public void addItem(Book newItem) {
        this.shopping.add(newItem);
    }

    public List<Book> getAllItems() {
        return shopping;
    }

    public void clear() {
        this.shopping.clear();
    }
}

Can someone point me in the direction of the key concept I am missing?

Answer 1

Take a look at JavaBean documentation.

If you have a JavaBean which has a JavaBean property, you access that property (in this case allItems) with a method get<propertyName> (in this case getAllItems()) or is<propertyName> when the property is a boolean. The actual name of the field is irrelevant to the JavaBean standard.

There is more to the JavaBean specification than just that. I recommend taking a look at the linked documentation.

So to access the allItems property of the shoppingCart bean, you will actually be triggering the getAllItems() method.