UML Weekend Crash Course™ - To Parent Directory

190
Saturday Evening
7:addProduct(characters)
1
Bill:
Customer
1:Order()
3:addItem(characters)
2
2:return Order
8:return true
5:return product available
3
Bill’s Order :
Order
4
5
4:productAvailable(characters)
6:[product available]
reduceInventory(product #, qty)
7
*Repeat steps 3 through
7 for each item the
customer wants to add
6
:Inventory
Figure 18-3 More detailed Collaboration diagram notation
The following descriptions refer to the numbered items in Figure 18-3 so that you can see
the notations used in context:
1. Object: This is a fully qualified object name, Bill, of the class Customer. The notation
is exactly the same as on the Sequence diagram.
2. Synchronous event or procedure call: A synchronous event is a message that
requires a reply, so you would expect to see a corresponding return message along
the same link sometime later in the sequence. Procedure calls are simply another
familiar way to describe this “ask and reply” form of interaction.
3. Return: Here is the return message for the message 1. Message 1 told the Order
class to create a new Order object, Bill’s Order. When the task of creating the
object is completed, it passes back a reference to the requestor, Bill.
4. Self-reference: A self-reference is simply an object talking to itself saying something
like, “It’s time for me to get more coffee.” In Figure 18-3, the Order is telling
itself to use the item information from step 3 to add another product to its list of
items.
5. Sequence number: Because the Collaboration diagram has no way of showing the
passage of time, it uses sequence numbers, like (4: ), to reveal the order of execution
for the messages. There are no standards for the numbering scheme, so common
sense and readability are your guides. The sequence numbers were optional on the
Sequence diagram. They are required on the Collaboration diagram.
6. Anonymous object: Reference 6 shows another example of valid object notation.
You do not have to name the instance if all you need to convey is that any object
of this type (Inventory) would behave in this manner.